diff options
Diffstat (limited to 'src/pkg/go/printer')
22 files changed, 10754 insertions, 0 deletions
diff --git a/src/pkg/go/printer/Makefile b/src/pkg/go/printer/Makefile new file mode 100644 index 000000000..6a71efc93 --- /dev/null +++ b/src/pkg/go/printer/Makefile @@ -0,0 +1,12 @@ +# Copyright 2009 The Go Authors. All rights reserved. +# Use of this source code is governed by a BSD-style +# license that can be found in the LICENSE file. + +include ../../../Make.inc + +TARG=go/printer +GOFILES=\ + printer.go\ + nodes.go\ + +include ../../../Make.pkg diff --git a/src/pkg/go/printer/nodes.go b/src/pkg/go/printer/nodes.go new file mode 100644 index 000000000..9cd975ec1 --- /dev/null +++ b/src/pkg/go/printer/nodes.go @@ -0,0 +1,1510 @@ +// Copyright 2009 The Go Authors. All rights reserved. +// Use of this source code is governed by a BSD-style +// license that can be found in the LICENSE file. + +// This file implements printing of AST nodes; specifically +// expressions, statements, declarations, and files. It uses +// the print functionality implemented in printer.go. + +package printer + +import ( + "bytes" + "go/ast" + "go/token" +) + +// Other formatting issues: +// - better comment formatting for /*-style comments at the end of a line (e.g. a declaration) +// when the comment spans multiple lines; if such a comment is just two lines, formatting is +// not idempotent +// - formatting of expression lists +// - should use blank instead of tab to separate one-line function bodies from +// the function header unless there is a group of consecutive one-liners + +// ---------------------------------------------------------------------------- +// Common AST nodes. + +// Print as many newlines as necessary (but at least min newlines) to get to +// the current line. ws is printed before the first line break. If newSection +// is set, the first line break is printed as formfeed. Returns true if any +// line break was printed; returns false otherwise. +// +// TODO(gri): linebreak may add too many lines if the next statement at "line" +// is preceded by comments because the computation of n assumes +// the current position before the comment and the target position +// after the comment. Thus, after interspersing such comments, the +// space taken up by them is not considered to reduce the number of +// linebreaks. At the moment there is no easy way to know about +// future (not yet interspersed) comments in this function. +// +func (p *printer) linebreak(line, min int, ws whiteSpace, newSection bool) (printedBreak bool) { + n := p.nlines(line-p.pos.Line, min) + if n > 0 { + p.print(ws) + if newSection { + p.print(formfeed) + n-- + } + for ; n > 0; n-- { + p.print(newline) + } + printedBreak = true + } + return +} + +// setComment sets g as the next comment if g != nil and if node comments +// are enabled - this mode is used when printing source code fragments such +// as exports only. It assumes that there are no other pending comments to +// intersperse. +func (p *printer) setComment(g *ast.CommentGroup) { + if g == nil || !p.useNodeComments { + return + } + if p.comments == nil { + // initialize p.comments lazily + p.comments = make([]*ast.CommentGroup, 1) + } else if p.cindex < len(p.comments) { + // for some reason there are pending comments; this + // should never happen - handle gracefully and flush + // all comments up to g, ignore anything after that + p.flush(p.fset.Position(g.List[0].Pos()), token.ILLEGAL) + } + p.comments[0] = g + p.cindex = 0 +} + +type exprListMode uint + +const ( + blankStart exprListMode = 1 << iota // print a blank before a non-empty list + blankEnd // print a blank after a non-empty list + commaSep // elements are separated by commas + commaTerm // list is optionally terminated by a comma + noIndent // no extra indentation in multi-line lists + periodSep // elements are separated by periods +) + +// Sets multiLine to true if the identifier list spans multiple lines. +// If indent is set, a multi-line identifier list is indented after the +// first linebreak encountered. +func (p *printer) identList(list []*ast.Ident, indent bool, multiLine *bool) { + // convert into an expression list so we can re-use exprList formatting + xlist := make([]ast.Expr, len(list)) + for i, x := range list { + xlist[i] = x + } + mode := commaSep + if !indent { + mode |= noIndent + } + p.exprList(token.NoPos, xlist, 1, mode, multiLine, token.NoPos) +} + +// Print a list of expressions. If the list spans multiple +// source lines, the original line breaks are respected between +// expressions. Sets multiLine to true if the list spans multiple +// lines. +// +// TODO(gri) Consider rewriting this to be independent of []ast.Expr +// so that we can use the algorithm for any kind of list +// (e.g., pass list via a channel over which to range). +func (p *printer) exprList(prev0 token.Pos, list []ast.Expr, depth int, mode exprListMode, multiLine *bool, next0 token.Pos) { + if len(list) == 0 { + return + } + + if mode&blankStart != 0 { + p.print(blank) + } + + prev := p.fset.Position(prev0) + next := p.fset.Position(next0) + line := p.fset.Position(list[0].Pos()).Line + endLine := p.fset.Position(list[len(list)-1].End()).Line + + if prev.IsValid() && prev.Line == line && line == endLine { + // all list entries on a single line + for i, x := range list { + if i > 0 { + if mode&commaSep != 0 { + p.print(token.COMMA) + } + p.print(blank) + } + p.expr0(x, depth, multiLine) + } + if mode&blankEnd != 0 { + p.print(blank) + } + return + } + + // list entries span multiple lines; + // use source code positions to guide line breaks + + // don't add extra indentation if noIndent is set; + // i.e., pretend that the first line is already indented + ws := ignore + if mode&noIndent == 0 { + ws = indent + } + + // the first linebreak is always a formfeed since this section must not + // depend on any previous formatting + prevBreak := -1 // index of last expression that was followed by a linebreak + if prev.IsValid() && prev.Line < line && p.linebreak(line, 0, ws, true) { + ws = ignore + *multiLine = true + prevBreak = 0 + } + + // initialize expression/key size: a zero value indicates expr/key doesn't fit on a single line + size := 0 + + // print all list elements + for i, x := range list { + prevLine := line + line = p.fset.Position(x.Pos()).Line + + // determine if the next linebreak, if any, needs to use formfeed: + // in general, use the entire node size to make the decision; for + // key:value expressions, use the key size + // TODO(gri) for a better result, should probably incorporate both + // the key and the node size into the decision process + useFF := true + + // determine element size: all bets are off if we don't have + // position information for the previous and next token (likely + // generated code - simply ignore the size in this case by setting + // it to 0) + prevSize := size + const infinity = 1e6 // larger than any source line + size = p.nodeSize(x, infinity) + pair, isPair := x.(*ast.KeyValueExpr) + if size <= infinity && prev.IsValid() && next.IsValid() { + // x fits on a single line + if isPair { + size = p.nodeSize(pair.Key, infinity) // size <= infinity + } + } else { + // size too large or we don't have good layout information + size = 0 + } + + // if the previous line and the current line had single- + // line-expressions and the key sizes are small or the + // the ratio between the key sizes does not exceed a + // threshold, align columns and do not use formfeed + if prevSize > 0 && size > 0 { + const smallSize = 20 + if prevSize <= smallSize && size <= smallSize { + useFF = false + } else { + const r = 4 // threshold + ratio := float64(size) / float64(prevSize) + useFF = ratio <= 1/r || r <= ratio + } + } + + if i > 0 { + switch { + case mode&commaSep != 0: + p.print(token.COMMA) + case mode&periodSep != 0: + p.print(token.PERIOD) + } + needsBlank := mode&periodSep == 0 // period-separated list elements don't need a blank + if prevLine < line && prevLine > 0 && line > 0 { + // lines are broken using newlines so comments remain aligned + // unless forceFF is set or there are multiple expressions on + // the same line in which case formfeed is used + if p.linebreak(line, 0, ws, useFF || prevBreak+1 < i) { + ws = ignore + *multiLine = true + prevBreak = i + needsBlank = false // we got a line break instead + } + } + if needsBlank { + p.print(blank) + } + } + + if isPair && size > 0 && len(list) > 1 { + // we have a key:value expression that fits onto one line and + // is in a list with more then one entry: use a column for the + // key such that consecutive entries can align if possible + p.expr(pair.Key, multiLine) + p.print(pair.Colon, token.COLON, vtab) + p.expr(pair.Value, multiLine) + } else { + p.expr0(x, depth, multiLine) + } + } + + if mode&commaTerm != 0 && next.IsValid() && p.pos.Line < next.Line { + // print a terminating comma if the next token is on a new line + p.print(token.COMMA) + if ws == ignore && mode&noIndent == 0 { + // unindent if we indented + p.print(unindent) + } + p.print(formfeed) // terminating comma needs a line break to look good + return + } + + if mode&blankEnd != 0 { + p.print(blank) + } + + if ws == ignore && mode&noIndent == 0 { + // unindent if we indented + p.print(unindent) + } +} + +// Sets multiLine to true if the the parameter list spans multiple lines. +func (p *printer) parameters(fields *ast.FieldList, multiLine *bool) { + p.print(fields.Opening, token.LPAREN) + if len(fields.List) > 0 { + var prevLine, line int + for i, par := range fields.List { + if i > 0 { + p.print(token.COMMA) + if len(par.Names) > 0 { + line = p.fset.Position(par.Names[0].Pos()).Line + } else { + line = p.fset.Position(par.Type.Pos()).Line + } + if 0 < prevLine && prevLine < line && p.linebreak(line, 0, ignore, true) { + *multiLine = true + } else { + p.print(blank) + } + } + if len(par.Names) > 0 { + p.identList(par.Names, false, multiLine) + p.print(blank) + } + p.expr(par.Type, multiLine) + prevLine = p.fset.Position(par.Type.Pos()).Line + } + } + p.print(fields.Closing, token.RPAREN) +} + +// Sets multiLine to true if the signature spans multiple lines. +func (p *printer) signature(params, result *ast.FieldList, multiLine *bool) { + p.parameters(params, multiLine) + n := result.NumFields() + if n > 0 { + p.print(blank) + if n == 1 && result.List[0].Names == nil { + // single anonymous result; no ()'s + p.expr(result.List[0].Type, multiLine) + return + } + p.parameters(result, multiLine) + } +} + +func identListSize(list []*ast.Ident, maxSize int) (size int) { + for i, x := range list { + if i > 0 { + size += 2 // ", " + } + size += len(x.Name) + if size >= maxSize { + break + } + } + return +} + +func (p *printer) isOneLineFieldList(list []*ast.Field) bool { + if len(list) != 1 { + return false // allow only one field + } + f := list[0] + if f.Tag != nil || f.Comment != nil { + return false // don't allow tags or comments + } + // only name(s) and type + const maxSize = 30 // adjust as appropriate, this is an approximate value + namesSize := identListSize(f.Names, maxSize) + if namesSize > 0 { + namesSize = 1 // blank between names and types + } + typeSize := p.nodeSize(f.Type, maxSize) + return namesSize+typeSize <= maxSize +} + +func (p *printer) setLineComment(text string) { + p.setComment(&ast.CommentGroup{[]*ast.Comment{&ast.Comment{token.NoPos, text}}}) +} + +func (p *printer) fieldList(fields *ast.FieldList, isStruct, isIncomplete bool) { + lbrace := fields.Opening + list := fields.List + rbrace := fields.Closing + srcIsOneLine := lbrace.IsValid() && rbrace.IsValid() && p.fset.Position(lbrace).Line == p.fset.Position(rbrace).Line + + if !isIncomplete && !p.commentBefore(p.fset.Position(rbrace)) && srcIsOneLine { + // possibly a one-line struct/interface + if len(list) == 0 { + // no blank between keyword and {} in this case + p.print(lbrace, token.LBRACE, rbrace, token.RBRACE) + return + } else if isStruct && p.isOneLineFieldList(list) { // for now ignore interfaces + // small enough - print on one line + // (don't use identList and ignore source line breaks) + p.print(lbrace, token.LBRACE, blank) + f := list[0] + for i, x := range f.Names { + if i > 0 { + p.print(token.COMMA, blank) + } + p.expr(x, ignoreMultiLine) + } + if len(f.Names) > 0 { + p.print(blank) + } + p.expr(f.Type, ignoreMultiLine) + p.print(blank, rbrace, token.RBRACE) + return + } + } + + // at least one entry or incomplete + p.print(blank, lbrace, token.LBRACE, indent, formfeed) + if isStruct { + + sep := vtab + if len(list) == 1 { + sep = blank + } + var ml bool + for i, f := range list { + if i > 0 { + p.linebreak(p.fset.Position(f.Pos()).Line, 1, ignore, ml) + } + ml = false + extraTabs := 0 + p.setComment(f.Doc) + if len(f.Names) > 0 { + // named fields + p.identList(f.Names, false, &ml) + p.print(sep) + p.expr(f.Type, &ml) + extraTabs = 1 + } else { + // anonymous field + p.expr(f.Type, &ml) + extraTabs = 2 + } + if f.Tag != nil { + if len(f.Names) > 0 && sep == vtab { + p.print(sep) + } + p.print(sep) + p.expr(f.Tag, &ml) + extraTabs = 0 + } + if f.Comment != nil { + for ; extraTabs > 0; extraTabs-- { + p.print(sep) + } + p.setComment(f.Comment) + } + } + if isIncomplete { + if len(list) > 0 { + p.print(formfeed) + } + p.flush(p.fset.Position(rbrace), token.RBRACE) // make sure we don't lose the last line comment + p.setLineComment("// contains filtered or unexported fields") + } + + } else { // interface + + var ml bool + for i, f := range list { + if i > 0 { + p.linebreak(p.fset.Position(f.Pos()).Line, 1, ignore, ml) + } + ml = false + p.setComment(f.Doc) + if ftyp, isFtyp := f.Type.(*ast.FuncType); isFtyp { + // method + p.expr(f.Names[0], &ml) + p.signature(ftyp.Params, ftyp.Results, &ml) + } else { + // embedded interface + p.expr(f.Type, &ml) + } + p.setComment(f.Comment) + } + if isIncomplete { + if len(list) > 0 { + p.print(formfeed) + } + p.flush(p.fset.Position(rbrace), token.RBRACE) // make sure we don't lose the last line comment + p.setLineComment("// contains filtered or unexported methods") + } + + } + p.print(unindent, formfeed, rbrace, token.RBRACE) +} + +// ---------------------------------------------------------------------------- +// Expressions + +func walkBinary(e *ast.BinaryExpr) (has4, has5 bool, maxProblem int) { + switch e.Op.Precedence() { + case 4: + has4 = true + case 5: + has5 = true + } + + switch l := e.X.(type) { + case *ast.BinaryExpr: + if l.Op.Precedence() < e.Op.Precedence() { + // parens will be inserted. + // pretend this is an *ast.ParenExpr and do nothing. + break + } + h4, h5, mp := walkBinary(l) + has4 = has4 || h4 + has5 = has5 || h5 + if maxProblem < mp { + maxProblem = mp + } + } + + switch r := e.Y.(type) { + case *ast.BinaryExpr: + if r.Op.Precedence() <= e.Op.Precedence() { + // parens will be inserted. + // pretend this is an *ast.ParenExpr and do nothing. + break + } + h4, h5, mp := walkBinary(r) + has4 = has4 || h4 + has5 = has5 || h5 + if maxProblem < mp { + maxProblem = mp + } + + case *ast.StarExpr: + if e.Op == token.QUO { // `*/` + maxProblem = 5 + } + + case *ast.UnaryExpr: + switch e.Op.String() + r.Op.String() { + case "/*", "&&", "&^": + maxProblem = 5 + case "++", "--": + if maxProblem < 4 { + maxProblem = 4 + } + } + } + return +} + +func cutoff(e *ast.BinaryExpr, depth int) int { + has4, has5, maxProblem := walkBinary(e) + if maxProblem > 0 { + return maxProblem + 1 + } + if has4 && has5 { + if depth == 1 { + return 5 + } + return 4 + } + if depth == 1 { + return 6 + } + return 4 +} + +func diffPrec(expr ast.Expr, prec int) int { + x, ok := expr.(*ast.BinaryExpr) + if !ok || prec != x.Op.Precedence() { + return 1 + } + return 0 +} + +func reduceDepth(depth int) int { + depth-- + if depth < 1 { + depth = 1 + } + return depth +} + +// Format the binary expression: decide the cutoff and then format. +// Let's call depth == 1 Normal mode, and depth > 1 Compact mode. +// (Algorithm suggestion by Russ Cox.) +// +// The precedences are: +// 5 * / % << >> & &^ +// 4 + - | ^ +// 3 == != < <= > >= +// 2 && +// 1 || +// +// The only decision is whether there will be spaces around levels 4 and 5. +// There are never spaces at level 6 (unary), and always spaces at levels 3 and below. +// +// To choose the cutoff, look at the whole expression but excluding primary +// expressions (function calls, parenthesized exprs), and apply these rules: +// +// 1) If there is a binary operator with a right side unary operand +// that would clash without a space, the cutoff must be (in order): +// +// /* 6 +// && 6 +// &^ 6 +// ++ 5 +// -- 5 +// +// (Comparison operators always have spaces around them.) +// +// 2) If there is a mix of level 5 and level 4 operators, then the cutoff +// is 5 (use spaces to distinguish precedence) in Normal mode +// and 4 (never use spaces) in Compact mode. +// +// 3) If there are no level 4 operators or no level 5 operators, then the +// cutoff is 6 (always use spaces) in Normal mode +// and 4 (never use spaces) in Compact mode. +// +// Sets multiLine to true if the binary expression spans multiple lines. +func (p *printer) binaryExpr(x *ast.BinaryExpr, prec1, cutoff, depth int, multiLine *bool) { + prec := x.Op.Precedence() + if prec < prec1 { + // parenthesis needed + // Note: The parser inserts an ast.ParenExpr node; thus this case + // can only occur if the AST is created in a different way. + p.print(token.LPAREN) + p.expr0(x, reduceDepth(depth), multiLine) // parentheses undo one level of depth + p.print(token.RPAREN) + return + } + + printBlank := prec < cutoff + + ws := indent + p.expr1(x.X, prec, depth+diffPrec(x.X, prec), multiLine) + if printBlank { + p.print(blank) + } + xline := p.pos.Line // before the operator (it may be on the next line!) + yline := p.fset.Position(x.Y.Pos()).Line + p.print(x.OpPos, x.Op) + if xline != yline && xline > 0 && yline > 0 { + // at least one line break, but respect an extra empty line + // in the source + if p.linebreak(yline, 1, ws, true) { + ws = ignore + *multiLine = true + printBlank = false // no blank after line break + } + } + if printBlank { + p.print(blank) + } + p.expr1(x.Y, prec+1, depth+1, multiLine) + if ws == ignore { + p.print(unindent) + } +} + +func isBinary(expr ast.Expr) bool { + _, ok := expr.(*ast.BinaryExpr) + return ok +} + +// If the expression contains one or more selector expressions, splits it into +// two expressions at the rightmost period. Writes entire expr to suffix when +// selector isn't found. Rewrites AST nodes for calls, index expressions and +// type assertions, all of which may be found in selector chains, to make them +// parts of the chain. +func splitSelector(expr ast.Expr) (body, suffix ast.Expr) { + switch x := expr.(type) { + case *ast.SelectorExpr: + body, suffix = x.X, x.Sel + return + case *ast.CallExpr: + body, suffix = splitSelector(x.Fun) + if body != nil { + suffix = &ast.CallExpr{suffix, x.Lparen, x.Args, x.Ellipsis, x.Rparen} + return + } + case *ast.IndexExpr: + body, suffix = splitSelector(x.X) + if body != nil { + suffix = &ast.IndexExpr{suffix, x.Lbrack, x.Index, x.Rbrack} + return + } + case *ast.SliceExpr: + body, suffix = splitSelector(x.X) + if body != nil { + suffix = &ast.SliceExpr{suffix, x.Lbrack, x.Low, x.High, x.Rbrack} + return + } + case *ast.TypeAssertExpr: + body, suffix = splitSelector(x.X) + if body != nil { + suffix = &ast.TypeAssertExpr{suffix, x.Type} + return + } + } + suffix = expr + return +} + +// Convert an expression into an expression list split at the periods of +// selector expressions. +func selectorExprList(expr ast.Expr) (list []ast.Expr) { + // split expression + for expr != nil { + var suffix ast.Expr + expr, suffix = splitSelector(expr) + list = append(list, suffix) + } + + // reverse list + for i, j := 0, len(list)-1; i < j; i, j = i+1, j-1 { + list[i], list[j] = list[j], list[i] + } + + return +} + +// Sets multiLine to true if the expression spans multiple lines. +func (p *printer) expr1(expr ast.Expr, prec1, depth int, multiLine *bool) { + p.print(expr.Pos()) + + switch x := expr.(type) { + case *ast.BadExpr: + p.print("BadExpr") + + case *ast.Ident: + p.print(x) + + case *ast.BinaryExpr: + if depth < 1 { + p.internalError("depth < 1:", depth) + depth = 1 + } + p.binaryExpr(x, prec1, cutoff(x, depth), depth, multiLine) + + case *ast.KeyValueExpr: + p.expr(x.Key, multiLine) + p.print(x.Colon, token.COLON, blank) + p.expr(x.Value, multiLine) + + case *ast.StarExpr: + const prec = token.UnaryPrec + if prec < prec1 { + // parenthesis needed + p.print(token.LPAREN) + p.print(token.MUL) + p.expr(x.X, multiLine) + p.print(token.RPAREN) + } else { + // no parenthesis needed + p.print(token.MUL) + p.expr(x.X, multiLine) + } + + case *ast.UnaryExpr: + const prec = token.UnaryPrec + if prec < prec1 { + // parenthesis needed + p.print(token.LPAREN) + p.expr(x, multiLine) + p.print(token.RPAREN) + } else { + // no parenthesis needed + p.print(x.Op) + if x.Op == token.RANGE { + // TODO(gri) Remove this code if it cannot be reached. + p.print(blank) + } + p.expr1(x.X, prec, depth, multiLine) + } + + case *ast.BasicLit: + p.print(x) + + case *ast.FuncLit: + p.expr(x.Type, multiLine) + p.funcBody(x.Body, p.distance(x.Type.Pos(), p.pos), true, multiLine) + + case *ast.ParenExpr: + if _, hasParens := x.X.(*ast.ParenExpr); hasParens { + // don't print parentheses around an already parenthesized expression + // TODO(gri) consider making this more general and incorporate precedence levels + p.expr0(x.X, reduceDepth(depth), multiLine) // parentheses undo one level of depth + } else { + p.print(token.LPAREN) + p.expr0(x.X, reduceDepth(depth), multiLine) // parentheses undo one level of depth + p.print(x.Rparen, token.RPAREN) + } + + case *ast.SelectorExpr: + parts := selectorExprList(expr) + p.exprList(token.NoPos, parts, depth, periodSep, multiLine, token.NoPos) + + case *ast.TypeAssertExpr: + p.expr1(x.X, token.HighestPrec, depth, multiLine) + p.print(token.PERIOD, token.LPAREN) + if x.Type != nil { + p.expr(x.Type, multiLine) + } else { + p.print(token.TYPE) + } + p.print(token.RPAREN) + + case *ast.IndexExpr: + // TODO(gri): should treat[] like parentheses and undo one level of depth + p.expr1(x.X, token.HighestPrec, 1, multiLine) + p.print(x.Lbrack, token.LBRACK) + p.expr0(x.Index, depth+1, multiLine) + p.print(x.Rbrack, token.RBRACK) + + case *ast.SliceExpr: + // TODO(gri): should treat[] like parentheses and undo one level of depth + p.expr1(x.X, token.HighestPrec, 1, multiLine) + p.print(x.Lbrack, token.LBRACK) + if x.Low != nil { + p.expr0(x.Low, depth+1, multiLine) + } + // blanks around ":" if both sides exist and either side is a binary expression + if depth <= 1 && x.Low != nil && x.High != nil && (isBinary(x.Low) || isBinary(x.High)) { + p.print(blank, token.COLON, blank) + } else { + p.print(token.COLON) + } + if x.High != nil { + p.expr0(x.High, depth+1, multiLine) + } + p.print(x.Rbrack, token.RBRACK) + + case *ast.CallExpr: + if len(x.Args) > 1 { + depth++ + } + p.expr1(x.Fun, token.HighestPrec, depth, multiLine) + p.print(x.Lparen, token.LPAREN) + p.exprList(x.Lparen, x.Args, depth, commaSep|commaTerm, multiLine, x.Rparen) + if x.Ellipsis.IsValid() { + p.print(x.Ellipsis, token.ELLIPSIS) + } + p.print(x.Rparen, token.RPAREN) + + case *ast.CompositeLit: + // composite literal elements that are composite literals themselves may have the type omitted + if x.Type != nil { + p.expr1(x.Type, token.HighestPrec, depth, multiLine) + } + p.print(x.Lbrace, token.LBRACE) + p.exprList(x.Lbrace, x.Elts, 1, commaSep|commaTerm, multiLine, x.Rbrace) + // do not insert extra line breaks because of comments before + // the closing '}' as it might break the code if there is no + // trailing ',' + p.print(noExtraLinebreak, x.Rbrace, token.RBRACE, noExtraLinebreak) + + case *ast.Ellipsis: + p.print(token.ELLIPSIS) + if x.Elt != nil { + p.expr(x.Elt, multiLine) + } + + case *ast.ArrayType: + p.print(token.LBRACK) + if x.Len != nil { + p.expr(x.Len, multiLine) + } + p.print(token.RBRACK) + p.expr(x.Elt, multiLine) + + case *ast.StructType: + p.print(token.STRUCT) + p.fieldList(x.Fields, true, x.Incomplete) + + case *ast.FuncType: + p.print(token.FUNC) + p.signature(x.Params, x.Results, multiLine) + + case *ast.InterfaceType: + p.print(token.INTERFACE) + p.fieldList(x.Methods, false, x.Incomplete) + + case *ast.MapType: + p.print(token.MAP, token.LBRACK) + p.expr(x.Key, multiLine) + p.print(token.RBRACK) + p.expr(x.Value, multiLine) + + case *ast.ChanType: + switch x.Dir { + case ast.SEND | ast.RECV: + p.print(token.CHAN) + case ast.RECV: + p.print(token.ARROW, token.CHAN) + case ast.SEND: + p.print(token.CHAN, token.ARROW) + } + p.print(blank) + p.expr(x.Value, multiLine) + + default: + panic("unreachable") + } + + return +} + +func (p *printer) expr0(x ast.Expr, depth int, multiLine *bool) { + p.expr1(x, token.LowestPrec, depth, multiLine) +} + +// Sets multiLine to true if the expression spans multiple lines. +func (p *printer) expr(x ast.Expr, multiLine *bool) { + const depth = 1 + p.expr1(x, token.LowestPrec, depth, multiLine) +} + +// ---------------------------------------------------------------------------- +// Statements + +// Print the statement list indented, but without a newline after the last statement. +// Extra line breaks between statements in the source are respected but at most one +// empty line is printed between statements. +func (p *printer) stmtList(list []ast.Stmt, _indent int, nextIsRBrace bool) { + // TODO(gri): fix _indent code + if _indent > 0 { + p.print(indent) + } + var multiLine bool + for i, s := range list { + // _indent == 0 only for lists of switch/select case clauses; + // in those cases each clause is a new section + p.linebreak(p.fset.Position(s.Pos()).Line, 1, ignore, i == 0 || _indent == 0 || multiLine) + multiLine = false + p.stmt(s, nextIsRBrace && i == len(list)-1, &multiLine) + } + if _indent > 0 { + p.print(unindent) + } +} + +// block prints an *ast.BlockStmt; it always spans at least two lines. +func (p *printer) block(s *ast.BlockStmt, indent int) { + p.print(s.Pos(), token.LBRACE) + p.stmtList(s.List, indent, true) + p.linebreak(p.fset.Position(s.Rbrace).Line, 1, ignore, true) + p.print(s.Rbrace, token.RBRACE) +} + +func isTypeName(x ast.Expr) bool { + switch t := x.(type) { + case *ast.Ident: + return true + case *ast.SelectorExpr: + return isTypeName(t.X) + } + return false +} + +func stripParens(x ast.Expr) ast.Expr { + if px, strip := x.(*ast.ParenExpr); strip { + // parentheses must not be stripped if there are any + // unparenthesized composite literals starting with + // a type name + ast.Inspect(px.X, func(node ast.Node) bool { + switch x := node.(type) { + case *ast.ParenExpr: + // parentheses protect enclosed composite literals + return false + case *ast.CompositeLit: + if isTypeName(x.Type) { + strip = false // do not strip parentheses + } + return false + } + // in all other cases, keep inspecting + return true + }) + if strip { + return stripParens(px.X) + } + } + return x +} + +func (p *printer) controlClause(isForStmt bool, init ast.Stmt, expr ast.Expr, post ast.Stmt) { + p.print(blank) + needsBlank := false + if init == nil && post == nil { + // no semicolons required + if expr != nil { + p.expr(stripParens(expr), ignoreMultiLine) + needsBlank = true + } + } else { + // all semicolons required + // (they are not separators, print them explicitly) + if init != nil { + p.stmt(init, false, ignoreMultiLine) + } + p.print(token.SEMICOLON, blank) + if expr != nil { + p.expr(stripParens(expr), ignoreMultiLine) + needsBlank = true + } + if isForStmt { + p.print(token.SEMICOLON, blank) + needsBlank = false + if post != nil { + p.stmt(post, false, ignoreMultiLine) + needsBlank = true + } + } + } + if needsBlank { + p.print(blank) + } +} + +// Sets multiLine to true if the statements spans multiple lines. +func (p *printer) stmt(stmt ast.Stmt, nextIsRBrace bool, multiLine *bool) { + p.print(stmt.Pos()) + + switch s := stmt.(type) { + case *ast.BadStmt: + p.print("BadStmt") + + case *ast.DeclStmt: + p.decl(s.Decl, multiLine) + + case *ast.EmptyStmt: + // nothing to do + + case *ast.LabeledStmt: + // a "correcting" unindent immediately following a line break + // is applied before the line break if there is no comment + // between (see writeWhitespace) + p.print(unindent) + p.expr(s.Label, multiLine) + p.print(s.Colon, token.COLON, indent) + if e, isEmpty := s.Stmt.(*ast.EmptyStmt); isEmpty { + if !nextIsRBrace { + p.print(newline, e.Pos(), token.SEMICOLON) + break + } + } else { + p.linebreak(p.fset.Position(s.Stmt.Pos()).Line, 1, ignore, true) + } + p.stmt(s.Stmt, nextIsRBrace, multiLine) + + case *ast.ExprStmt: + const depth = 1 + p.expr0(s.X, depth, multiLine) + + case *ast.SendStmt: + const depth = 1 + p.expr0(s.Chan, depth, multiLine) + p.print(blank, s.Arrow, token.ARROW, blank) + p.expr0(s.Value, depth, multiLine) + + case *ast.IncDecStmt: + const depth = 1 + p.expr0(s.X, depth+1, multiLine) + p.print(s.TokPos, s.Tok) + + case *ast.AssignStmt: + var depth = 1 + if len(s.Lhs) > 1 && len(s.Rhs) > 1 { + depth++ + } + p.exprList(s.Pos(), s.Lhs, depth, commaSep, multiLine, s.TokPos) + p.print(blank, s.TokPos, s.Tok) + p.exprList(s.TokPos, s.Rhs, depth, blankStart|commaSep, multiLine, token.NoPos) + + case *ast.GoStmt: + p.print(token.GO, blank) + p.expr(s.Call, multiLine) + + case *ast.DeferStmt: + p.print(token.DEFER, blank) + p.expr(s.Call, multiLine) + + case *ast.ReturnStmt: + p.print(token.RETURN) + if s.Results != nil { + p.exprList(s.Pos(), s.Results, 1, blankStart|commaSep, multiLine, token.NoPos) + } + + case *ast.BranchStmt: + p.print(s.Tok) + if s.Label != nil { + p.print(blank) + p.expr(s.Label, multiLine) + } + + case *ast.BlockStmt: + p.block(s, 1) + *multiLine = true + + case *ast.IfStmt: + p.print(token.IF) + p.controlClause(false, s.Init, s.Cond, nil) + p.block(s.Body, 1) + *multiLine = true + if s.Else != nil { + p.print(blank, token.ELSE, blank) + switch s.Else.(type) { + case *ast.BlockStmt, *ast.IfStmt: + p.stmt(s.Else, nextIsRBrace, ignoreMultiLine) + default: + p.print(token.LBRACE, indent, formfeed) + p.stmt(s.Else, true, ignoreMultiLine) + p.print(unindent, formfeed, token.RBRACE) + } + } + + case *ast.CaseClause: + if s.List != nil { + p.print(token.CASE) + p.exprList(s.Pos(), s.List, 1, blankStart|commaSep, multiLine, s.Colon) + } else { + p.print(token.DEFAULT) + } + p.print(s.Colon, token.COLON) + p.stmtList(s.Body, 1, nextIsRBrace) + + case *ast.SwitchStmt: + p.print(token.SWITCH) + p.controlClause(false, s.Init, s.Tag, nil) + p.block(s.Body, 0) + *multiLine = true + + case *ast.TypeSwitchStmt: + p.print(token.SWITCH) + if s.Init != nil { + p.print(blank) + p.stmt(s.Init, false, ignoreMultiLine) + p.print(token.SEMICOLON) + } + p.print(blank) + p.stmt(s.Assign, false, ignoreMultiLine) + p.print(blank) + p.block(s.Body, 0) + *multiLine = true + + case *ast.CommClause: + if s.Comm != nil { + p.print(token.CASE, blank) + p.stmt(s.Comm, false, ignoreMultiLine) + } else { + p.print(token.DEFAULT) + } + p.print(s.Colon, token.COLON) + p.stmtList(s.Body, 1, nextIsRBrace) + + case *ast.SelectStmt: + p.print(token.SELECT, blank) + body := s.Body + if len(body.List) == 0 && !p.commentBefore(p.fset.Position(body.Rbrace)) { + // print empty select statement w/o comments on one line + p.print(body.Lbrace, token.LBRACE, body.Rbrace, token.RBRACE) + } else { + p.block(body, 0) + *multiLine = true + } + + case *ast.ForStmt: + p.print(token.FOR) + p.controlClause(true, s.Init, s.Cond, s.Post) + p.block(s.Body, 1) + *multiLine = true + + case *ast.RangeStmt: + p.print(token.FOR, blank) + p.expr(s.Key, multiLine) + if s.Value != nil { + p.print(token.COMMA, blank) + p.expr(s.Value, multiLine) + } + p.print(blank, s.TokPos, s.Tok, blank, token.RANGE, blank) + p.expr(stripParens(s.X), multiLine) + p.print(blank) + p.block(s.Body, 1) + *multiLine = true + + default: + panic("unreachable") + } + + return +} + +// ---------------------------------------------------------------------------- +// Declarations + +// The keepTypeColumn function determines if the type column of a series of +// consecutive const or var declarations must be kept, or if initialization +// values (V) can be placed in the type column (T) instead. The i'th entry +// in the result slice is true if the type column in spec[i] must be kept. +// +// For example, the declaration: +// +// const ( +// foobar int = 42 // comment +// x = 7 // comment +// foo +// bar = 991 +// ) +// +// leads to the type/values matrix below. A run of value columns (V) can +// be moved into the type column if there is no type for any of the values +// in that column (we only move entire columns so that they align properly). +// +// matrix formatted result +// matrix +// T V -> T V -> true there is a T and so the type +// - V - V true column must be kept +// - - - - false +// - V V - false V is moved into T column +// +func keepTypeColumn(specs []ast.Spec) []bool { + m := make([]bool, len(specs)) + + populate := func(i, j int, keepType bool) { + if keepType { + for ; i < j; i++ { + m[i] = true + } + } + } + + i0 := -1 // if i0 >= 0 we are in a run and i0 is the start of the run + var keepType bool + for i, s := range specs { + t := s.(*ast.ValueSpec) + if t.Values != nil { + if i0 < 0 { + // start of a run of ValueSpecs with non-nil Values + i0 = i + keepType = false + } + } else { + if i0 >= 0 { + // end of a run + populate(i0, i, keepType) + i0 = -1 + } + } + if t.Type != nil { + keepType = true + } + } + if i0 >= 0 { + // end of a run + populate(i0, len(specs), keepType) + } + + return m +} + +func (p *printer) valueSpec(s *ast.ValueSpec, keepType, doIndent bool, multiLine *bool) { + p.setComment(s.Doc) + p.identList(s.Names, doIndent, multiLine) // always present + extraTabs := 3 + if s.Type != nil || keepType { + p.print(vtab) + extraTabs-- + } + if s.Type != nil { + p.expr(s.Type, multiLine) + } + if s.Values != nil { + p.print(vtab, token.ASSIGN) + p.exprList(token.NoPos, s.Values, 1, blankStart|commaSep, multiLine, token.NoPos) + extraTabs-- + } + if s.Comment != nil { + for ; extraTabs > 0; extraTabs-- { + p.print(vtab) + } + p.setComment(s.Comment) + } +} + +// The parameter n is the number of specs in the group. If doIndent is set, +// multi-line identifier lists in the spec are indented when the first +// linebreak is encountered. +// Sets multiLine to true if the spec spans multiple lines. +// +func (p *printer) spec(spec ast.Spec, n int, doIndent bool, multiLine *bool) { + switch s := spec.(type) { + case *ast.ImportSpec: + p.setComment(s.Doc) + if s.Name != nil { + p.expr(s.Name, multiLine) + p.print(blank) + } + p.expr(s.Path, multiLine) + p.setComment(s.Comment) + + case *ast.ValueSpec: + if n != 1 { + p.internalError("expected n = 1; got", n) + } + p.setComment(s.Doc) + p.identList(s.Names, doIndent, multiLine) // always present + if s.Type != nil { + p.print(blank) + p.expr(s.Type, multiLine) + } + if s.Values != nil { + p.print(blank, token.ASSIGN) + p.exprList(token.NoPos, s.Values, 1, blankStart|commaSep, multiLine, token.NoPos) + } + p.setComment(s.Comment) + + case *ast.TypeSpec: + p.setComment(s.Doc) + p.expr(s.Name, multiLine) + if n == 1 { + p.print(blank) + } else { + p.print(vtab) + } + p.expr(s.Type, multiLine) + p.setComment(s.Comment) + + default: + panic("unreachable") + } +} + +// Sets multiLine to true if the declaration spans multiple lines. +func (p *printer) genDecl(d *ast.GenDecl, multiLine *bool) { + p.setComment(d.Doc) + p.print(d.Pos(), d.Tok, blank) + + if d.Lparen.IsValid() { + // group of parenthesized declarations + p.print(d.Lparen, token.LPAREN) + if n := len(d.Specs); n > 0 { + p.print(indent, formfeed) + if n > 1 && (d.Tok == token.CONST || d.Tok == token.VAR) { + // two or more grouped const/var declarations: + // determine if the type column must be kept + keepType := keepTypeColumn(d.Specs) + var ml bool + for i, s := range d.Specs { + if i > 0 { + p.linebreak(p.fset.Position(s.Pos()).Line, 1, ignore, ml) + } + ml = false + p.valueSpec(s.(*ast.ValueSpec), keepType[i], false, &ml) + } + } else { + var ml bool + for i, s := range d.Specs { + if i > 0 { + p.linebreak(p.fset.Position(s.Pos()).Line, 1, ignore, ml) + } + ml = false + p.spec(s, n, false, &ml) + } + } + p.print(unindent, formfeed) + *multiLine = true + } + p.print(d.Rparen, token.RPAREN) + + } else { + // single declaration + p.spec(d.Specs[0], 1, true, multiLine) + } +} + +// nodeSize determines the size of n in chars after formatting. +// The result is <= maxSize if the node fits on one line with at +// most maxSize chars and the formatted output doesn't contain +// any control chars. Otherwise, the result is > maxSize. +// +func (p *printer) nodeSize(n ast.Node, maxSize int) (size int) { + // nodeSize invokes the printer, which may invoke nodeSize + // recursively. For deep composite literal nests, this can + // lead to an exponential algorithm. Remember previous + // results to prune the recursion (was issue 1628). + if size, found := p.nodeSizes[n]; found { + return size + } + + size = maxSize + 1 // assume n doesn't fit + p.nodeSizes[n] = size + + // nodeSize computation must be independent of particular + // style so that we always get the same decision; print + // in RawFormat + cfg := Config{Mode: RawFormat} + var buf bytes.Buffer + if _, err := cfg.fprint(&buf, p.fset, n, p.nodeSizes); err != nil { + return + } + if buf.Len() <= maxSize { + for _, ch := range buf.Bytes() { + if ch < ' ' { + return + } + } + size = buf.Len() // n fits + p.nodeSizes[n] = size + } + return +} + +func (p *printer) isOneLineFunc(b *ast.BlockStmt, headerSize int) bool { + pos1 := b.Pos() + pos2 := b.Rbrace + if pos1.IsValid() && pos2.IsValid() && p.fset.Position(pos1).Line != p.fset.Position(pos2).Line { + // opening and closing brace are on different lines - don't make it a one-liner + return false + } + if len(b.List) > 5 || p.commentBefore(p.fset.Position(pos2)) { + // too many statements or there is a comment inside - don't make it a one-liner + return false + } + // otherwise, estimate body size + const maxSize = 100 + bodySize := 0 + for i, s := range b.List { + if i > 0 { + bodySize += 2 // space for a semicolon and blank + } + bodySize += p.nodeSize(s, maxSize) + } + return headerSize+bodySize <= maxSize +} + +// Sets multiLine to true if the function body spans multiple lines. +func (p *printer) funcBody(b *ast.BlockStmt, headerSize int, isLit bool, multiLine *bool) { + if b == nil { + return + } + + if p.isOneLineFunc(b, headerSize) { + sep := vtab + if isLit { + sep = blank + } + p.print(sep, b.Lbrace, token.LBRACE) + if len(b.List) > 0 { + p.print(blank) + for i, s := range b.List { + if i > 0 { + p.print(token.SEMICOLON, blank) + } + p.stmt(s, i == len(b.List)-1, ignoreMultiLine) + } + p.print(blank) + } + p.print(b.Rbrace, token.RBRACE) + return + } + + p.print(blank) + p.block(b, 1) + *multiLine = true +} + +// distance returns the column difference between from and to if both +// are on the same line; if they are on different lines (or unknown) +// the result is infinity. +func (p *printer) distance(from0 token.Pos, to token.Position) int { + from := p.fset.Position(from0) + if from.IsValid() && to.IsValid() && from.Line == to.Line { + return to.Column - from.Column + } + return infinity +} + +// Sets multiLine to true if the declaration spans multiple lines. +func (p *printer) funcDecl(d *ast.FuncDecl, multiLine *bool) { + p.setComment(d.Doc) + p.print(d.Pos(), token.FUNC, blank) + if d.Recv != nil { + p.parameters(d.Recv, multiLine) // method: print receiver + p.print(blank) + } + p.expr(d.Name, multiLine) + p.signature(d.Type.Params, d.Type.Results, multiLine) + p.funcBody(d.Body, p.distance(d.Pos(), p.pos), false, multiLine) +} + +// Sets multiLine to true if the declaration spans multiple lines. +func (p *printer) decl(decl ast.Decl, multiLine *bool) { + switch d := decl.(type) { + case *ast.BadDecl: + p.print(d.Pos(), "BadDecl") + case *ast.GenDecl: + p.genDecl(d, multiLine) + case *ast.FuncDecl: + p.funcDecl(d, multiLine) + default: + panic("unreachable") + } +} + +// ---------------------------------------------------------------------------- +// Files + +func declToken(decl ast.Decl) (tok token.Token) { + tok = token.ILLEGAL + switch d := decl.(type) { + case *ast.GenDecl: + tok = d.Tok + case *ast.FuncDecl: + tok = token.FUNC + } + return +} + +func (p *printer) file(src *ast.File) { + p.setComment(src.Doc) + p.print(src.Pos(), token.PACKAGE, blank) + p.expr(src.Name, ignoreMultiLine) + + if len(src.Decls) > 0 { + tok := token.ILLEGAL + for _, d := range src.Decls { + prev := tok + tok = declToken(d) + // if the declaration token changed (e.g., from CONST to TYPE) + // print an empty line between top-level declarations + min := 1 + if prev != tok { + min = 2 + } + p.linebreak(p.fset.Position(d.Pos()).Line, min, ignore, false) + p.decl(d, ignoreMultiLine) + } + } + + p.print(newline) +} diff --git a/src/pkg/go/printer/performance_test.go b/src/pkg/go/printer/performance_test.go new file mode 100644 index 000000000..84fb2808e --- /dev/null +++ b/src/pkg/go/printer/performance_test.go @@ -0,0 +1,58 @@ +// Copyright 2009 The Go Authors. All rights reserved. +// Use of this source code is governed by a BSD-style +// license that can be found in the LICENSE file. + +// This file implements a simple printer performance benchmark: +// gotest -bench=BenchmarkPrint + +package printer + +import ( + "bytes" + "go/ast" + "go/parser" + "io" + "io/ioutil" + "log" + "testing" +) + +var testfile *ast.File + +func testprint(out io.Writer, file *ast.File) { + if _, err := (&Config{TabIndent | UseSpaces, 8}).Fprint(out, fset, file); err != nil { + log.Fatalf("print error: %s", err) + } +} + +// cannot initialize in init because (printer) Fprint launches goroutines. +func initialize() { + const filename = "testdata/parser.go" + + src, err := ioutil.ReadFile(filename) + if err != nil { + log.Fatalf("%s", err) + } + + file, err := parser.ParseFile(fset, filename, src, parser.ParseComments) + if err != nil { + log.Fatalf("%s", err) + } + + var buf bytes.Buffer + testprint(&buf, file) + if !bytes.Equal(buf.Bytes(), src) { + log.Fatalf("print error: %s not idempotent", filename) + } + + testfile = file +} + +func BenchmarkPrint(b *testing.B) { + if testfile == nil { + initialize() + } + for i := 0; i < b.N; i++ { + testprint(ioutil.Discard, testfile) + } +} diff --git a/src/pkg/go/printer/printer.go b/src/pkg/go/printer/printer.go new file mode 100644 index 000000000..871fefa0c --- /dev/null +++ b/src/pkg/go/printer/printer.go @@ -0,0 +1,1012 @@ +// Copyright 2009 The Go Authors. All rights reserved. +// Use of this source code is governed by a BSD-style +// license that can be found in the LICENSE file. + +// Package printer implements printing of AST nodes. +package printer + +import ( + "bytes" + "fmt" + "go/ast" + "go/token" + "io" + "os" + "path/filepath" + "runtime" + "tabwriter" +) + +const debug = false // enable for debugging + + +type whiteSpace int + +const ( + ignore = whiteSpace(0) + blank = whiteSpace(' ') + vtab = whiteSpace('\v') + newline = whiteSpace('\n') + formfeed = whiteSpace('\f') + indent = whiteSpace('>') + unindent = whiteSpace('<') +) + +var ( + esc = []byte{tabwriter.Escape} + htab = []byte{'\t'} + htabs = []byte("\t\t\t\t\t\t\t\t") + newlines = []byte("\n\n\n\n\n\n\n\n") // more than the max determined by nlines + formfeeds = []byte("\f\f\f\f\f\f\f\f") // more than the max determined by nlines +) + +// Special positions +var noPos token.Position // use noPos when a position is needed but not known +var infinity = 1 << 30 + +// Use ignoreMultiLine if the multiLine information is not important. +var ignoreMultiLine = new(bool) + +// A pmode value represents the current printer mode. +type pmode int + +const ( + inLiteral pmode = 1 << iota + noExtraLinebreak +) + +type printer struct { + // Configuration (does not change after initialization) + output io.Writer + Config + fset *token.FileSet + errors chan os.Error + + // Current state + written int // number of bytes written + indent int // current indentation + mode pmode // current printer mode + lastTok token.Token // the last token printed (token.ILLEGAL if it's whitespace) + + // Reused buffers + wsbuf []whiteSpace // delayed white space + litbuf bytes.Buffer // for creation of escaped literals and comments + + // The (possibly estimated) position in the generated output; + // in AST space (i.e., pos is set whenever a token position is + // known accurately, and updated dependending on what has been + // written). + pos token.Position + + // The value of pos immediately after the last item has been + // written using writeItem. + last token.Position + + // The list of all source comments, in order of appearance. + comments []*ast.CommentGroup // may be nil + cindex int // current comment index + useNodeComments bool // if not set, ignore lead and line comments of nodes + + // Cache of already computed node sizes. + nodeSizes map[ast.Node]int +} + +func (p *printer) init(output io.Writer, cfg *Config, fset *token.FileSet, nodeSizes map[ast.Node]int) { + p.output = output + p.Config = *cfg + p.fset = fset + p.errors = make(chan os.Error) + p.wsbuf = make([]whiteSpace, 0, 16) // whitespace sequences are short + p.nodeSizes = nodeSizes +} + +func (p *printer) internalError(msg ...interface{}) { + if debug { + fmt.Print(p.pos.String() + ": ") + fmt.Println(msg...) + panic("go/printer") + } +} + +// escape escapes string s by bracketing it with tabwriter.Escape. +// Escaped strings pass through tabwriter unchanged. (Note that +// valid Go programs cannot contain tabwriter.Escape bytes since +// they do not appear in legal UTF-8 sequences). +// +func (p *printer) escape(s string) string { + p.litbuf.Reset() + p.litbuf.WriteByte(tabwriter.Escape) + p.litbuf.WriteString(s) + p.litbuf.WriteByte(tabwriter.Escape) + return p.litbuf.String() +} + +// nlines returns the adjusted number of linebreaks given the desired number +// of breaks n such that min <= result <= max. +// +func (p *printer) nlines(n, min int) int { + const max = 2 // max. number of newlines + switch { + case n < min: + return min + case n > max: + return max + } + return n +} + +// write0 writes raw (uninterpreted) data to p.output and handles errors. +// write0 does not indent after newlines, and does not HTML-escape or update p.pos. +// +func (p *printer) write0(data []byte) { + if len(data) > 0 { + n, err := p.output.Write(data) + p.written += n + if err != nil { + p.errors <- err + runtime.Goexit() + } + } +} + +// write interprets data and writes it to p.output. It inserts indentation +// after a line break unless in a tabwriter escape sequence. +// It updates p.pos as a side-effect. +// +func (p *printer) write(data []byte) { + i0 := 0 + for i, b := range data { + switch b { + case '\n', '\f': + // write segment ending in b + p.write0(data[i0 : i+1]) + + // update p.pos + p.pos.Offset += i + 1 - i0 + p.pos.Line++ + p.pos.Column = 1 + + if p.mode&inLiteral == 0 { + // write indentation + // use "hard" htabs - indentation columns + // must not be discarded by the tabwriter + j := p.indent + for ; j > len(htabs); j -= len(htabs) { + p.write0(htabs) + } + p.write0(htabs[0:j]) + + // update p.pos + p.pos.Offset += p.indent + p.pos.Column += p.indent + } + + // next segment start + i0 = i + 1 + + case tabwriter.Escape: + p.mode ^= inLiteral + + // ignore escape chars introduced by printer - they are + // invisible and must not affect p.pos (was issue #1089) + p.pos.Offset-- + p.pos.Column-- + } + } + + // write remaining segment + p.write0(data[i0:]) + + // update p.pos + d := len(data) - i0 + p.pos.Offset += d + p.pos.Column += d +} + +func (p *printer) writeNewlines(n int, useFF bool) { + if n > 0 { + n = p.nlines(n, 0) + if useFF { + p.write(formfeeds[0:n]) + } else { + p.write(newlines[0:n]) + } + } +} + +// writeItem writes data at position pos. data is the text corresponding to +// a single lexical token, but may also be comment text. pos is the actual +// (or at least very accurately estimated) position of the data in the original +// source text. writeItem updates p.last to the position immediately following +// the data. +// +func (p *printer) writeItem(pos token.Position, data string) { + if pos.IsValid() { + // continue with previous position if we don't have a valid pos + if p.last.IsValid() && p.last.Filename != pos.Filename { + // the file has changed - reset state + // (used when printing merged ASTs of different files + // e.g., the result of ast.MergePackageFiles) + p.indent = 0 + p.mode = 0 + p.wsbuf = p.wsbuf[0:0] + } + p.pos = pos + } + if debug { + // do not update p.pos - use write0 + _, filename := filepath.Split(pos.Filename) + p.write0([]byte(fmt.Sprintf("[%s:%d:%d]", filename, pos.Line, pos.Column))) + } + p.write([]byte(data)) + p.last = p.pos +} + +// writeCommentPrefix writes the whitespace before a comment. +// If there is any pending whitespace, it consumes as much of +// it as is likely to help position the comment nicely. +// pos is the comment position, next the position of the item +// after all pending comments, prev is the previous comment in +// a group of comments (or nil), and isKeyword indicates if the +// next item is a keyword. +// +func (p *printer) writeCommentPrefix(pos, next token.Position, prev *ast.Comment, isKeyword bool) { + if p.written == 0 { + // the comment is the first item to be printed - don't write any whitespace + return + } + + if pos.IsValid() && pos.Filename != p.last.Filename { + // comment in a different file - separate with newlines (writeNewlines will limit the number) + p.writeNewlines(10, true) + return + } + + if pos.Line == p.last.Line && (prev == nil || prev.Text[1] != '/') { + // comment on the same line as last item: + // separate with at least one separator + hasSep := false + if prev == nil { + // first comment of a comment group + j := 0 + for i, ch := range p.wsbuf { + switch ch { + case blank: + // ignore any blanks before a comment + p.wsbuf[i] = ignore + continue + case vtab: + // respect existing tabs - important + // for proper formatting of commented structs + hasSep = true + continue + case indent: + // apply pending indentation + continue + } + j = i + break + } + p.writeWhitespace(j) + } + // make sure there is at least one separator + if !hasSep { + if pos.Line == next.Line { + // next item is on the same line as the comment + // (which must be a /*-style comment): separate + // with a blank instead of a tab + p.write([]byte{' '}) + } else { + p.write(htab) + } + } + + } else { + // comment on a different line: + // separate with at least one line break + if prev == nil { + // first comment of a comment group + j := 0 + for i, ch := range p.wsbuf { + switch ch { + case blank, vtab: + // ignore any horizontal whitespace before line breaks + p.wsbuf[i] = ignore + continue + case indent: + // apply pending indentation + continue + case unindent: + // if the next token is a keyword, apply the outdent + // if it appears that the comment is aligned with the + // keyword; otherwise assume the outdent is part of a + // closing block and stop (this scenario appears with + // comments before a case label where the comments + // apply to the next case instead of the current one) + if isKeyword && pos.Column == next.Column { + continue + } + case newline, formfeed: + // TODO(gri): may want to keep formfeed info in some cases + p.wsbuf[i] = ignore + } + j = i + break + } + p.writeWhitespace(j) + } + // use formfeeds to break columns before a comment; + // this is analogous to using formfeeds to separate + // individual lines of /*-style comments - but make + // sure there is at least one line break if the previous + // comment was a line comment + n := pos.Line - p.last.Line // if !pos.IsValid(), pos.Line == 0, and n will be 0 + if n <= 0 && prev != nil && prev.Text[1] == '/' { + n = 1 + } + p.writeNewlines(n, true) + } +} + +// TODO(gri): It should be possible to convert the code below from using +// []byte to string and in the process eliminate some conversions. + +// Split comment text into lines +func split(text []byte) [][]byte { + // count lines (comment text never ends in a newline) + n := 1 + for _, c := range text { + if c == '\n' { + n++ + } + } + + // split + lines := make([][]byte, n) + n = 0 + i := 0 + for j, c := range text { + if c == '\n' { + lines[n] = text[i:j] // exclude newline + i = j + 1 // discard newline + n++ + } + } + lines[n] = text[i:] + + return lines +} + +func isBlank(s []byte) bool { + for _, b := range s { + if b > ' ' { + return false + } + } + return true +} + +func commonPrefix(a, b []byte) []byte { + i := 0 + for i < len(a) && i < len(b) && a[i] == b[i] && (a[i] <= ' ' || a[i] == '*') { + i++ + } + return a[0:i] +} + +func stripCommonPrefix(lines [][]byte) { + if len(lines) < 2 { + return // at most one line - nothing to do + } + // len(lines) >= 2 + + // The heuristic in this function tries to handle a few + // common patterns of /*-style comments: Comments where + // the opening /* and closing */ are aligned and the + // rest of the comment text is aligned and indented with + // blanks or tabs, cases with a vertical "line of stars" + // on the left, and cases where the closing */ is on the + // same line as the last comment text. + + // Compute maximum common white prefix of all but the first, + // last, and blank lines, and replace blank lines with empty + // lines (the first line starts with /* and has no prefix). + // In case of two-line comments, consider the last line for + // the prefix computation since otherwise the prefix would + // be empty. + // + // Note that the first and last line are never empty (they + // contain the opening /* and closing */ respectively) and + // thus they can be ignored by the blank line check. + var prefix []byte + if len(lines) > 2 { + for i, line := range lines[1 : len(lines)-1] { + switch { + case isBlank(line): + lines[1+i] = nil // range starts at line 1 + case prefix == nil: + prefix = commonPrefix(line, line) + default: + prefix = commonPrefix(prefix, line) + } + } + } else { // len(lines) == 2 + line := lines[1] + prefix = commonPrefix(line, line) + } + + /* + * Check for vertical "line of stars" and correct prefix accordingly. + */ + lineOfStars := false + if i := bytes.Index(prefix, []byte{'*'}); i >= 0 { + // Line of stars present. + if i > 0 && prefix[i-1] == ' ' { + i-- // remove trailing blank from prefix so stars remain aligned + } + prefix = prefix[0:i] + lineOfStars = true + } else { + // No line of stars present. + // Determine the white space on the first line after the /* + // and before the beginning of the comment text, assume two + // blanks instead of the /* unless the first character after + // the /* is a tab. If the first comment line is empty but + // for the opening /*, assume up to 3 blanks or a tab. This + // whitespace may be found as suffix in the common prefix. + first := lines[0] + if isBlank(first[2:]) { + // no comment text on the first line: + // reduce prefix by up to 3 blanks or a tab + // if present - this keeps comment text indented + // relative to the /* and */'s if it was indented + // in the first place + i := len(prefix) + for n := 0; n < 3 && i > 0 && prefix[i-1] == ' '; n++ { + i-- + } + if i == len(prefix) && i > 0 && prefix[i-1] == '\t' { + i-- + } + prefix = prefix[0:i] + } else { + // comment text on the first line + suffix := make([]byte, len(first)) + n := 2 // start after opening /* + for n < len(first) && first[n] <= ' ' { + suffix[n] = first[n] + n++ + } + if n > 2 && suffix[2] == '\t' { + // assume the '\t' compensates for the /* + suffix = suffix[2:n] + } else { + // otherwise assume two blanks + suffix[0], suffix[1] = ' ', ' ' + suffix = suffix[0:n] + } + // Shorten the computed common prefix by the length of + // suffix, if it is found as suffix of the prefix. + if bytes.HasSuffix(prefix, suffix) { + prefix = prefix[0 : len(prefix)-len(suffix)] + } + } + } + + // Handle last line: If it only contains a closing */, align it + // with the opening /*, otherwise align the text with the other + // lines. + last := lines[len(lines)-1] + closing := []byte("*/") + i := bytes.Index(last, closing) + if isBlank(last[0:i]) { + // last line only contains closing */ + var sep []byte + if lineOfStars { + // insert an aligning blank + sep = []byte{' '} + } + lines[len(lines)-1] = bytes.Join([][]byte{prefix, closing}, sep) + } else { + // last line contains more comment text - assume + // it is aligned like the other lines + prefix = commonPrefix(prefix, last) + } + + // Remove the common prefix from all but the first and empty lines. + for i, line := range lines[1:] { + if len(line) != 0 { + lines[1+i] = line[len(prefix):] // range starts at line 1 + } + } +} + +func (p *printer) writeComment(comment *ast.Comment) { + text := comment.Text + + // shortcut common case of //-style comments + if text[1] == '/' { + p.writeItem(p.fset.Position(comment.Pos()), p.escape(text)) + return + } + + // for /*-style comments, print line by line and let the + // write function take care of the proper indentation + lines := split([]byte(text)) + stripCommonPrefix(lines) + + // write comment lines, separated by formfeed, + // without a line break after the last line + linebreak := formfeeds[0:1] + pos := p.fset.Position(comment.Pos()) + for i, line := range lines { + if i > 0 { + p.write(linebreak) + pos = p.pos + } + if len(line) > 0 { + p.writeItem(pos, p.escape(string(line))) + } + } +} + +// writeCommentSuffix writes a line break after a comment if indicated +// and processes any leftover indentation information. If a line break +// is needed, the kind of break (newline vs formfeed) depends on the +// pending whitespace. writeCommentSuffix returns true if a pending +// formfeed was dropped from the whitespace buffer. +// +func (p *printer) writeCommentSuffix(needsLinebreak bool) (droppedFF bool) { + for i, ch := range p.wsbuf { + switch ch { + case blank, vtab: + // ignore trailing whitespace + p.wsbuf[i] = ignore + case indent, unindent: + // don't lose indentation information + case newline, formfeed: + // if we need a line break, keep exactly one + // but remember if we dropped any formfeeds + if needsLinebreak { + needsLinebreak = false + } else { + if ch == formfeed { + droppedFF = true + } + p.wsbuf[i] = ignore + } + } + } + p.writeWhitespace(len(p.wsbuf)) + + // make sure we have a line break + if needsLinebreak { + p.write([]byte{'\n'}) + } + + return +} + +// intersperseComments consumes all comments that appear before the next token +// tok and prints it together with the buffered whitespace (i.e., the whitespace +// that needs to be written before the next token). A heuristic is used to mix +// the comments and whitespace. intersperseComments returns true if a pending +// formfeed was dropped from the whitespace buffer. +// +func (p *printer) intersperseComments(next token.Position, tok token.Token) (droppedFF bool) { + var last *ast.Comment + for ; p.commentBefore(next); p.cindex++ { + for _, c := range p.comments[p.cindex].List { + p.writeCommentPrefix(p.fset.Position(c.Pos()), next, last, tok.IsKeyword()) + p.writeComment(c) + last = c + } + } + + if last != nil { + if last.Text[1] == '*' && p.fset.Position(last.Pos()).Line == next.Line { + // the last comment is a /*-style comment and the next item + // follows on the same line: separate with an extra blank + p.write([]byte{' '}) + } + // ensure that there is a line break after a //-style comment, + // before a closing '}' unless explicitly disabled, or at eof + needsLinebreak := + last.Text[1] == '/' || + tok == token.RBRACE && p.mode&noExtraLinebreak == 0 || + tok == token.EOF + return p.writeCommentSuffix(needsLinebreak) + } + + // no comment was written - we should never reach here since + // intersperseComments should not be called in that case + p.internalError("intersperseComments called without pending comments") + return false +} + +// whiteWhitespace writes the first n whitespace entries. +func (p *printer) writeWhitespace(n int) { + // write entries + var data [1]byte + for i := 0; i < n; i++ { + switch ch := p.wsbuf[i]; ch { + case ignore: + // ignore! + case indent: + p.indent++ + case unindent: + p.indent-- + if p.indent < 0 { + p.internalError("negative indentation:", p.indent) + p.indent = 0 + } + case newline, formfeed: + // A line break immediately followed by a "correcting" + // unindent is swapped with the unindent - this permits + // proper label positioning. If a comment is between + // the line break and the label, the unindent is not + // part of the comment whitespace prefix and the comment + // will be positioned correctly indented. + if i+1 < n && p.wsbuf[i+1] == unindent { + // Use a formfeed to terminate the current section. + // Otherwise, a long label name on the next line leading + // to a wide column may increase the indentation column + // of lines before the label; effectively leading to wrong + // indentation. + p.wsbuf[i], p.wsbuf[i+1] = unindent, formfeed + i-- // do it again + continue + } + fallthrough + default: + data[0] = byte(ch) + p.write(data[0:]) + } + } + + // shift remaining entries down + i := 0 + for ; n < len(p.wsbuf); n++ { + p.wsbuf[i] = p.wsbuf[n] + i++ + } + p.wsbuf = p.wsbuf[0:i] +} + +// ---------------------------------------------------------------------------- +// Printing interface + + +func mayCombine(prev token.Token, next byte) (b bool) { + switch prev { + case token.INT: + b = next == '.' // 1. + case token.ADD: + b = next == '+' // ++ + case token.SUB: + b = next == '-' // -- + case token.QUO: + b = next == '*' // /* + case token.LSS: + b = next == '-' || next == '<' // <- or << + case token.AND: + b = next == '&' || next == '^' // && or &^ + } + return +} + +// print prints a list of "items" (roughly corresponding to syntactic +// tokens, but also including whitespace and formatting information). +// It is the only print function that should be called directly from +// any of the AST printing functions in nodes.go. +// +// Whitespace is accumulated until a non-whitespace token appears. Any +// comments that need to appear before that token are printed first, +// taking into account the amount and structure of any pending white- +// space for best comment placement. Then, any leftover whitespace is +// printed, followed by the actual token. +// +func (p *printer) print(args ...interface{}) { + for _, f := range args { + next := p.pos // estimated position of next item + var data string + var tok token.Token + + switch x := f.(type) { + case pmode: + // toggle printer mode + p.mode ^= x + case whiteSpace: + if x == ignore { + // don't add ignore's to the buffer; they + // may screw up "correcting" unindents (see + // LabeledStmt) + break + } + i := len(p.wsbuf) + if i == cap(p.wsbuf) { + // Whitespace sequences are very short so this should + // never happen. Handle gracefully (but possibly with + // bad comment placement) if it does happen. + p.writeWhitespace(i) + i = 0 + } + p.wsbuf = p.wsbuf[0 : i+1] + p.wsbuf[i] = x + case *ast.Ident: + data = x.Name + tok = token.IDENT + case *ast.BasicLit: + data = p.escape(x.Value) + tok = x.Kind + case token.Token: + s := x.String() + if mayCombine(p.lastTok, s[0]) { + // the previous and the current token must be + // separated by a blank otherwise they combine + // into a different incorrect token sequence + // (except for token.INT followed by a '.' this + // should never happen because it is taken care + // of via binary expression formatting) + if len(p.wsbuf) != 0 { + p.internalError("whitespace buffer not empty") + } + p.wsbuf = p.wsbuf[0:1] + p.wsbuf[0] = ' ' + } + data = s + tok = x + case token.Pos: + if x.IsValid() { + next = p.fset.Position(x) // accurate position of next item + } + tok = p.lastTok + default: + fmt.Fprintf(os.Stderr, "print: unsupported argument type %T\n", f) + panic("go/printer type") + } + p.lastTok = tok + p.pos = next + + if data != "" { + droppedFF := p.flush(next, tok) + + // intersperse extra newlines if present in the source + // (don't do this in flush as it will cause extra newlines + // at the end of a file) - use formfeeds if we dropped one + // before + p.writeNewlines(next.Line-p.pos.Line, droppedFF) + + p.writeItem(next, data) + } + } +} + +// commentBefore returns true iff the current comment occurs +// before the next position in the source code. +// +func (p *printer) commentBefore(next token.Position) bool { + return p.cindex < len(p.comments) && p.fset.Position(p.comments[p.cindex].List[0].Pos()).Offset < next.Offset +} + +// Flush prints any pending comments and whitespace occurring +// textually before the position of the next token tok. Flush +// returns true if a pending formfeed character was dropped +// from the whitespace buffer as a result of interspersing +// comments. +// +func (p *printer) flush(next token.Position, tok token.Token) (droppedFF bool) { + if p.commentBefore(next) { + // if there are comments before the next item, intersperse them + droppedFF = p.intersperseComments(next, tok) + } else { + // otherwise, write any leftover whitespace + p.writeWhitespace(len(p.wsbuf)) + } + return +} + +// ---------------------------------------------------------------------------- +// Trimmer + +// A trimmer is an io.Writer filter for stripping tabwriter.Escape +// characters, trailing blanks and tabs, and for converting formfeed +// and vtab characters into newlines and htabs (in case no tabwriter +// is used). Text bracketed by tabwriter.Escape characters is passed +// through unchanged. +// +type trimmer struct { + output io.Writer + state int + space bytes.Buffer +} + +// trimmer is implemented as a state machine. +// It can be in one of the following states: +const ( + inSpace = iota // inside space + inEscape // inside text bracketed by tabwriter.Escapes + inText // inside text +) + +// Design note: It is tempting to eliminate extra blanks occurring in +// whitespace in this function as it could simplify some +// of the blanks logic in the node printing functions. +// However, this would mess up any formatting done by +// the tabwriter. + +func (p *trimmer) Write(data []byte) (n int, err os.Error) { + // invariants: + // p.state == inSpace: + // p.space is unwritten + // p.state == inEscape, inText: + // data[m:n] is unwritten + m := 0 + var b byte + for n, b = range data { + if b == '\v' { + b = '\t' // convert to htab + } + switch p.state { + case inSpace: + switch b { + case '\t', ' ': + p.space.WriteByte(b) // WriteByte returns no errors + case '\n', '\f': + p.space.Reset() // discard trailing space + _, err = p.output.Write(newlines[0:1]) // write newline + case tabwriter.Escape: + _, err = p.output.Write(p.space.Bytes()) + p.state = inEscape + m = n + 1 // +1: skip tabwriter.Escape + default: + _, err = p.output.Write(p.space.Bytes()) + p.state = inText + m = n + } + case inEscape: + if b == tabwriter.Escape { + _, err = p.output.Write(data[m:n]) + p.state = inSpace + p.space.Reset() + } + case inText: + switch b { + case '\t', ' ': + _, err = p.output.Write(data[m:n]) + p.state = inSpace + p.space.Reset() + p.space.WriteByte(b) // WriteByte returns no errors + case '\n', '\f': + _, err = p.output.Write(data[m:n]) + p.state = inSpace + p.space.Reset() + _, err = p.output.Write(newlines[0:1]) // write newline + case tabwriter.Escape: + _, err = p.output.Write(data[m:n]) + p.state = inEscape + m = n + 1 // +1: skip tabwriter.Escape + } + default: + panic("unreachable") + } + if err != nil { + return + } + } + n = len(data) + + switch p.state { + case inEscape, inText: + _, err = p.output.Write(data[m:n]) + p.state = inSpace + p.space.Reset() + } + + return +} + +// ---------------------------------------------------------------------------- +// Public interface + +// General printing is controlled with these Config.Mode flags. +const ( + RawFormat uint = 1 << iota // do not use a tabwriter; if set, UseSpaces is ignored + TabIndent // use tabs for indentation independent of UseSpaces + UseSpaces // use spaces instead of tabs for alignment +) + +// A Config node controls the output of Fprint. +type Config struct { + Mode uint // default: 0 + Tabwidth int // default: 8 +} + +// fprint implements Fprint and takes a nodesSizes map for setting up the printer state. +func (cfg *Config) fprint(output io.Writer, fset *token.FileSet, node interface{}, nodeSizes map[ast.Node]int) (int, os.Error) { + // redirect output through a trimmer to eliminate trailing whitespace + // (Input to a tabwriter must be untrimmed since trailing tabs provide + // formatting information. The tabwriter could provide trimming + // functionality but no tabwriter is used when RawFormat is set.) + output = &trimmer{output: output} + + // setup tabwriter if needed and redirect output + var tw *tabwriter.Writer + if cfg.Mode&RawFormat == 0 { + minwidth := cfg.Tabwidth + + padchar := byte('\t') + if cfg.Mode&UseSpaces != 0 { + padchar = ' ' + } + + twmode := tabwriter.DiscardEmptyColumns + if cfg.Mode&TabIndent != 0 { + minwidth = 0 + twmode |= tabwriter.TabIndent + } + + tw = tabwriter.NewWriter(output, minwidth, cfg.Tabwidth, 1, padchar, twmode) + output = tw + } + + // setup printer and print node + var p printer + p.init(output, cfg, fset, nodeSizes) + go func() { + switch n := node.(type) { + case ast.Expr: + p.useNodeComments = true + p.expr(n, ignoreMultiLine) + case ast.Stmt: + p.useNodeComments = true + // A labeled statement will un-indent to position the + // label. Set indent to 1 so we don't get indent "underflow". + if _, labeledStmt := n.(*ast.LabeledStmt); labeledStmt { + p.indent = 1 + } + p.stmt(n, false, ignoreMultiLine) + case ast.Decl: + p.useNodeComments = true + p.decl(n, ignoreMultiLine) + case ast.Spec: + p.useNodeComments = true + p.spec(n, 1, false, ignoreMultiLine) + case *ast.File: + p.comments = n.Comments + p.useNodeComments = n.Comments == nil + p.file(n) + default: + p.errors <- fmt.Errorf("printer.Fprint: unsupported node type %T", n) + runtime.Goexit() + } + p.flush(token.Position{Offset: infinity, Line: infinity}, token.EOF) + p.errors <- nil // no errors + }() + err := <-p.errors // wait for completion of goroutine + + // flush tabwriter, if any + if tw != nil { + tw.Flush() // ignore errors + } + + return p.written, err +} + +// Fprint "pretty-prints" an AST node to output and returns the number +// of bytes written and an error (if any) for a given configuration cfg. +// Position information is interpreted relative to the file set fset. +// The node type must be *ast.File, or assignment-compatible to ast.Expr, +// ast.Decl, ast.Spec, or ast.Stmt. +// +func (cfg *Config) Fprint(output io.Writer, fset *token.FileSet, node interface{}) (int, os.Error) { + return cfg.fprint(output, fset, node, make(map[ast.Node]int)) +} + +// Fprint "pretty-prints" an AST node to output. +// It calls Config.Fprint with default settings. +// +func Fprint(output io.Writer, fset *token.FileSet, node interface{}) os.Error { + _, err := (&Config{Tabwidth: 8}).Fprint(output, fset, node) // don't care about number of bytes written + return err +} diff --git a/src/pkg/go/printer/printer_test.go b/src/pkg/go/printer/printer_test.go new file mode 100644 index 000000000..ff2d906b5 --- /dev/null +++ b/src/pkg/go/printer/printer_test.go @@ -0,0 +1,194 @@ +// Copyright 2009 The Go Authors. All rights reserved. +// Use of this source code is governed by a BSD-style +// license that can be found in the LICENSE file. + +package printer + +import ( + "bytes" + "flag" + "io/ioutil" + "go/ast" + "go/parser" + "go/token" + "path/filepath" + "testing" + "time" +) + +const ( + dataDir = "testdata" + tabwidth = 8 +) + +var update = flag.Bool("update", false, "update golden files") + +var fset = token.NewFileSet() + +func lineString(text []byte, i int) string { + i0 := i + for i < len(text) && text[i] != '\n' { + i++ + } + return string(text[i0:i]) +} + +type checkMode uint + +const ( + export checkMode = 1 << iota + rawFormat +) + +func runcheck(t *testing.T, source, golden string, mode checkMode) { + // parse source + prog, err := parser.ParseFile(fset, source, nil, parser.ParseComments) + if err != nil { + t.Error(err) + return + } + + // filter exports if necessary + if mode&export != 0 { + ast.FileExports(prog) // ignore result + prog.Comments = nil // don't print comments that are not in AST + } + + // determine printer configuration + cfg := Config{Tabwidth: tabwidth} + if mode&rawFormat != 0 { + cfg.Mode |= RawFormat + } + + // format source + var buf bytes.Buffer + if _, err := cfg.Fprint(&buf, fset, prog); err != nil { + t.Error(err) + } + res := buf.Bytes() + + // update golden files if necessary + if *update { + if err := ioutil.WriteFile(golden, res, 0644); err != nil { + t.Error(err) + } + return + } + + // get golden + gld, err := ioutil.ReadFile(golden) + if err != nil { + t.Error(err) + return + } + + // compare lengths + if len(res) != len(gld) { + t.Errorf("len = %d, expected %d (= len(%s))", len(res), len(gld), golden) + } + + // compare contents + for i, line, offs := 0, 1, 0; i < len(res) && i < len(gld); i++ { + ch := res[i] + if ch != gld[i] { + t.Errorf("%s:%d:%d: %s", source, line, i-offs+1, lineString(res, offs)) + t.Errorf("%s:%d:%d: %s", golden, line, i-offs+1, lineString(gld, offs)) + t.Error() + return + } + if ch == '\n' { + line++ + offs = i + 1 + } + } +} + +func check(t *testing.T, source, golden string, mode checkMode) { + // start a timer to produce a time-out signal + tc := make(chan int) + go func() { + time.Sleep(10e9) // plenty of a safety margin, even for very slow machines + tc <- 0 + }() + + // run the test + cc := make(chan int) + go func() { + runcheck(t, source, golden, mode) + cc <- 0 + }() + + // wait for the first finisher + select { + case <-tc: + // test running past time out + t.Errorf("%s: running too slowly", source) + case <-cc: + // test finished within alloted time margin + } +} + +type entry struct { + source, golden string + mode checkMode +} + +// Use gotest -update to create/update the respective golden files. +var data = []entry{ + {"empty.input", "empty.golden", 0}, + {"comments.input", "comments.golden", 0}, + {"comments.input", "comments.x", export}, + {"linebreaks.input", "linebreaks.golden", 0}, + {"expressions.input", "expressions.golden", 0}, + {"expressions.input", "expressions.raw", rawFormat}, + {"declarations.input", "declarations.golden", 0}, + {"statements.input", "statements.golden", 0}, + {"slow.input", "slow.golden", 0}, +} + +func TestFiles(t *testing.T) { + for i, e := range data { + source := filepath.Join(dataDir, e.source) + golden := filepath.Join(dataDir, e.golden) + check(t, source, golden, e.mode) + // TODO(gri) check that golden is idempotent + //check(t, golden, golden, e.mode) + if testing.Short() && i >= 3 { + break + } + } +} + +// TestLineComments, using a simple test case, checks that consequtive line +// comments are properly terminated with a newline even if the AST position +// information is incorrect. +// +func TestLineComments(t *testing.T) { + const src = `// comment 1 + // comment 2 + // comment 3 + package main + ` + + fset := token.NewFileSet() + ast1, err1 := parser.ParseFile(fset, "", src, parser.ParseComments) + if err1 != nil { + panic(err1) + } + + var buf bytes.Buffer + fset = token.NewFileSet() // use the wrong file set + Fprint(&buf, fset, ast1) + + nlines := 0 + for _, ch := range buf.Bytes() { + if ch == '\n' { + nlines++ + } + } + + const expected = 3 + if nlines < expected { + t.Errorf("got %d, expected %d\n", nlines, expected) + } +} diff --git a/src/pkg/go/printer/testdata/comments.golden b/src/pkg/go/printer/testdata/comments.golden new file mode 100644 index 000000000..7b332252c --- /dev/null +++ b/src/pkg/go/printer/testdata/comments.golden @@ -0,0 +1,473 @@ +// Copyright 2009 The Go Authors. All rights reserved. +// Use of this source code is governed by a BSD-style +// license that can be found in the LICENSE file. + +// This is a package for testing comment placement by go/printer. +// +package main + +import "fmt" // fmt + +const c0 = 0 // zero +const ( + c1 = iota // c1 + c2 // c2 +) + +// Alignment of comments in declarations> +const ( + _ T = iota // comment + _ // comment + _ // comment + _ = iota + 10 + _ // comments + + _ = 10 // comment + _ T = 20 // comment +) + +const ( + _____ = iota // foo + _ // bar + _ = 0 // bal + _ // bat +) + +const ( + _ T = iota // comment + _ // comment + _ // comment + _ = iota + 10 + _ // comment + _ = 10 + _ = 20 // comment + _ T = 0 // comment +) + +// The SZ struct; it is empty. +type SZ struct{} + +// The S0 struct; no field is exported. +type S0 struct { + int + x, y, z int // 3 unexported fields +} + +// The S1 struct; some fields are not exported. +type S1 struct { + S0 + A, B, C float // 3 exported fields + D, b, c int // 2 unexported fields +} + +// The S2 struct; all fields are exported. +type S2 struct { + S1 + A, B, C float // 3 exported fields +} + +// The IZ interface; it is empty. +type SZ interface{} + +// The I0 interface; no method is exported. +type I0 interface { + f(x int) int // unexported method +} + +// The I1 interface; some methods are not exported. +type I1 interface { + I0 + F(x float) float // exported methods + g(x int) int // unexported method +} + +// The I2 interface; all methods are exported. +type I2 interface { + I0 + F(x float) float // exported method + G(x float) float // exported method +} + +// The S3 struct; all comments except for the last one must appear in the export. +type S3 struct { + // lead comment for F1 + F1 int // line comment for F1 + // lead comment for F2 + F2 int // line comment for F2 + f3 int // f3 is not exported +} + +// This comment group should be separated +// with a newline from the next comment +// group. + +// This comment should NOT be associated with the next declaration. + +var x int // x +var () + +// This comment SHOULD be associated with the next declaration. +func f0() { + const pi = 3.14 // pi + var s1 struct{} /* an empty struct */ /* foo */ + // a struct constructor + // -------------------- + var s2 struct{} = struct{}{} + x := pi +} +// +// NO SPACE HERE +// +func f1() { + f0() + /* 1 */ + // 2 + /* 3 */ + /* 4 */ + f0() +} + +func _() { + // this comment should be properly indented +} + +func _(x int) int { + if x < 0 { // the tab printed before this comment's // must not affect the remaining lines + return -x // this statement should be properly indented + } + if x < 0 { /* the tab printed before this comment's /* must not affect the remaining lines */ + return -x // this statement should be properly indented + } + return x +} + +func typeswitch(x interface{}) { + switch v := x.(type) { + case bool, int, float: + case string: + default: + } + + switch x.(type) { + } + + switch v0, ok := x.(int); v := x.(type) { + } + + switch v0, ok := x.(int); x.(type) { + case byte: // this comment should be on the same line as the keyword + // this comment should be normally indented + _ = 0 + case bool, int, float: + // this comment should be indented + case string: + default: + // this comment should be indented + } + // this comment should not be indented +} + +func _() { + /* freestanding comment + aligned line + aligned line + */ +} + +func _() { + /* freestanding comment + aligned line + aligned line + */ +} + +func _() { + /* freestanding comment + aligned line + aligned line */ +} + +func _() { + /* freestanding comment + aligned line + aligned line + */ +} + +func _() { + /* freestanding comment + aligned line + aligned line + */ +} + +func _() { + /* freestanding comment + aligned line + aligned line */ +} + +func _() { + /* + freestanding comment + aligned line + aligned line + */ +} + +func _() { + /* + freestanding comment + aligned line + aligned line + */ +} + +func _() { + /* + freestanding comment + aligned line + aligned line */ +} + +func _() { + /* + freestanding comment + aligned line + aligned line + */ +} + +func _() { + /* + freestanding comment + aligned line + aligned line + */ +} + +func _() { + /* + freestanding comment + aligned line + aligned line */ +} + +func _() { + /* freestanding comment + aligned line + */ +} + +func _() { + /* freestanding comment + aligned line + */ +} + +func _() { + /* freestanding comment + aligned line */ +} + +func _() { + /* freestanding comment + aligned line + */ +} + +func _() { + /* freestanding comment + aligned line + */ +} + +func _() { + /* freestanding comment + aligned line */ +} + +func _() { + /* + freestanding comment + aligned line + */ +} + +func _() { + /* + freestanding comment + aligned line + */ +} + +func _() { + /* + freestanding comment + aligned line */ +} + +func _() { + /* + freestanding comment + aligned line + */ +} + +func _() { + /* + freestanding comment + aligned line + */ +} + +func _() { + /* + freestanding comment + aligned line */ +} + +/* + * line + * of + * stars + */ + +/* another line + * of + * stars */ + +/* and another line + * of + * stars */ + +/* a line of + * stars */ + +/* and another line of + * stars */ + +/* a line of stars + */ + +/* and another line of + */ + +/* a line of stars + */ + +/* and another line of + */ + +/* +aligned in middle +here + not here +*/ + +/* +blank line in middle: + +with no leading spaces on blank line. +*/ + +/* + aligned in middle + here + not here +*/ + +/* + blank line in middle: + + with no leading spaces on blank line. +*/ + +func _() { + /* + * line + * of + * stars + */ + + /* + aligned in middle + here + not here + */ + + /* + blank line in middle: + + with no leading spaces on blank line. + */ +} + +// Some interesting interspersed comments +func _( /* this */ x /* is */ /* an */ int) { +} + +func _( /* no params */ ) {} + +func _() { + f( /* no args */ ) +} + +func ( /* comment1 */ T /* comment2 */ ) _() {} + +func _() { /* one-line functions with comments are formatted as multi-line functions */ +} + +func _() { + _ = 0 + /* closing curly brace should be on new line */ +} + +func _() { + _ = []int{0, 1 /* don't introduce a newline after this comment - was issue 1365 */ } +} + +// Comments immediately adjacent to punctuation (for which the go/printer +// may only have estimated position information) must remain after the punctuation. +func _() { + _ = T{ + 1, // comment after comma + 2, /* comment after comma */ + 3, // comment after comma + } + _ = T{ + 1, // comment after comma + 2, /* comment after comma */ + 3, // comment after comma + } + _ = T{ + /* comment before literal */ 1, + 2, /* comment before comma - ok to move after comma */ + 3, /* comment before comma - ok to move after comma */ + } + + for i = 0; // comment after semicolon + i < 9; /* comment after semicolon */ + i++ { // comment after opening curly brace + } + + // TODO(gri) the last comment in this example should be aligned */ + for i = 0; // comment after semicolon + i < 9; /* comment before semicolon - ok to move after semicolon */ + i++ /* comment before opening curly brace */ { + } +} + +// Line comments with tabs +func _() { + var finput *bufio.Reader // input file + var stderr *bufio.Writer + var ftable *bufio.Writer // y.go file + var foutput *bufio.Writer // y.output file + + var oflag string // -o [y.go] - y.go file + var vflag string // -v [y.output] - y.output file + var lflag bool // -l - disable line directives +} + +/* This comment is the last entry in this file. It must be printed and should be followed by a newline */ diff --git a/src/pkg/go/printer/testdata/comments.input b/src/pkg/go/printer/testdata/comments.input new file mode 100644 index 000000000..2a9a86b68 --- /dev/null +++ b/src/pkg/go/printer/testdata/comments.input @@ -0,0 +1,483 @@ +// Copyright 2009 The Go Authors. All rights reserved. +// Use of this source code is governed by a BSD-style +// license that can be found in the LICENSE file. + +// This is a package for testing comment placement by go/printer. +// +package main + +import "fmt" // fmt + +const c0 = 0 // zero +const ( + c1 = iota // c1 + c2 // c2 +) + +// Alignment of comments in declarations> +const ( + _ T = iota // comment + _ // comment + _ // comment + _ = iota+10 + _ // comments + + _ = 10 // comment + _ T = 20 // comment +) + +const ( + _____ = iota // foo + _ // bar + _ = 0 // bal + _ // bat +) + +const ( + _ T = iota // comment + _ // comment + _ // comment + _ = iota + 10 + _ // comment + _ = 10 + _ = 20 // comment + _ T = 0 // comment +) + +// The SZ struct; it is empty. +type SZ struct {} + +// The S0 struct; no field is exported. +type S0 struct { + int + x, y, z int // 3 unexported fields +} + +// The S1 struct; some fields are not exported. +type S1 struct { + S0 + A, B, C float // 3 exported fields + D, b, c int // 2 unexported fields +} + +// The S2 struct; all fields are exported. +type S2 struct { + S1 + A, B, C float // 3 exported fields +} + +// The IZ interface; it is empty. +type SZ interface {} + +// The I0 interface; no method is exported. +type I0 interface { + f(x int) int // unexported method +} + +// The I1 interface; some methods are not exported. +type I1 interface { + I0 + F(x float) float // exported methods + g(x int) int // unexported method +} + +// The I2 interface; all methods are exported. +type I2 interface { + I0 + F(x float) float // exported method + G(x float) float // exported method +} + +// The S3 struct; all comments except for the last one must appear in the export. +type S3 struct { + // lead comment for F1 + F1 int // line comment for F1 + // lead comment for F2 + F2 int // line comment for F2 + f3 int // f3 is not exported +} + +// This comment group should be separated +// with a newline from the next comment +// group. + +// This comment should NOT be associated with the next declaration. + +var x int // x +var () + + +// This comment SHOULD be associated with the next declaration. +func f0() { + const pi = 3.14 // pi + var s1 struct {} /* an empty struct */ /* foo */ + // a struct constructor + // -------------------- + var s2 struct {} = struct {}{} + x := pi +} +// +// NO SPACE HERE +// +func f1() { + f0() + /* 1 */ + // 2 + /* 3 */ + /* 4 */ + f0() +} + + +func _() { + // this comment should be properly indented +} + + +func _(x int) int { + if x < 0 { // the tab printed before this comment's // must not affect the remaining lines + return -x // this statement should be properly indented + } + if x < 0 { /* the tab printed before this comment's /* must not affect the remaining lines */ + return -x // this statement should be properly indented + } + return x +} + + +func typeswitch(x interface{}) { + switch v := x.(type) { + case bool, int, float: + case string: + default: + } + + switch x.(type) { + } + + switch v0, ok := x.(int); v := x.(type) { + } + + switch v0, ok := x.(int); x.(type) { + case byte: // this comment should be on the same line as the keyword + // this comment should be normally indented + _ = 0 + case bool, int, float: + // this comment should be indented + case string: + default: + // this comment should be indented + } + // this comment should not be indented +} + +func _() { + /* freestanding comment + aligned line + aligned line + */ +} + +func _() { + /* freestanding comment + aligned line + aligned line + */ +} + +func _() { + /* freestanding comment + aligned line + aligned line */ +} + +func _() { + /* freestanding comment + aligned line + aligned line + */ +} + +func _() { + /* freestanding comment + aligned line + aligned line + */ +} + +func _() { + /* freestanding comment + aligned line + aligned line */ +} + + +func _() { + /* + freestanding comment + aligned line + aligned line + */ +} + +func _() { + /* + freestanding comment + aligned line + aligned line + */ +} + +func _() { + /* + freestanding comment + aligned line + aligned line */ +} + +func _() { + /* + freestanding comment + aligned line + aligned line + */ +} + +func _() { + /* + freestanding comment + aligned line + aligned line + */ +} + +func _() { + /* + freestanding comment + aligned line + aligned line */ +} + +func _() { + /* freestanding comment + aligned line + */ +} + +func _() { + /* freestanding comment + aligned line + */ +} + +func _() { + /* freestanding comment + aligned line */ +} + +func _() { + /* freestanding comment + aligned line + */ +} + +func _() { + /* freestanding comment + aligned line + */ +} + +func _() { + /* freestanding comment + aligned line */ +} + + +func _() { + /* + freestanding comment + aligned line + */ +} + +func _() { + /* + freestanding comment + aligned line + */ +} + +func _() { + /* + freestanding comment + aligned line */ +} + +func _() { + /* + freestanding comment + aligned line + */ +} + +func _() { + /* + freestanding comment + aligned line + */ +} + +func _() { + /* + freestanding comment + aligned line */ +} + +/* + * line + * of + * stars + */ + +/* another line + * of + * stars */ + +/* and another line + * of + * stars */ + +/* a line of + * stars */ + +/* and another line of + * stars */ + +/* a line of stars +*/ + +/* and another line of +*/ + +/* a line of stars + */ + +/* and another line of + */ + +/* +aligned in middle +here + not here +*/ + +/* +blank line in middle: + +with no leading spaces on blank line. +*/ + +/* + aligned in middle + here + not here +*/ + +/* + blank line in middle: + + with no leading spaces on blank line. +*/ + +func _() { + /* + * line + * of + * stars + */ + + /* + aligned in middle + here + not here + */ + + /* + blank line in middle: + + with no leading spaces on blank line. +*/ +} + + +// Some interesting interspersed comments +func _(/* this */x/* is *//* an */ int) { +} + +func _(/* no params */) {} + +func _() { + f(/* no args */) +} + +func (/* comment1 */ T /* comment2 */) _() {} + +func _() { /* one-line functions with comments are formatted as multi-line functions */ } + +func _() { + _ = 0 + /* closing curly brace should be on new line */ } + +func _() { + _ = []int{0, 1 /* don't introduce a newline after this comment - was issue 1365 */} +} + + +// Comments immediately adjacent to punctuation (for which the go/printer +// may only have estimated position information) must remain after the punctuation. +func _() { + _ = T{ + 1, // comment after comma + 2, /* comment after comma */ + 3 , // comment after comma + } + _ = T{ + 1 ,// comment after comma + 2 ,/* comment after comma */ + 3,// comment after comma + } + _ = T{ + /* comment before literal */1, + 2/* comment before comma - ok to move after comma */, + 3 /* comment before comma - ok to move after comma */ , + } + + for + i=0;// comment after semicolon + i<9;/* comment after semicolon */ + i++{// comment after opening curly brace + } + + // TODO(gri) the last comment in this example should be aligned */ + for + i=0;// comment after semicolon + i<9/* comment before semicolon - ok to move after semicolon */; + i++ /* comment before opening curly brace */ { + } +} + + +// Line comments with tabs +func _() { +var finput *bufio.Reader // input file +var stderr *bufio.Writer +var ftable *bufio.Writer // y.go file +var foutput *bufio.Writer // y.output file + +var oflag string // -o [y.go] - y.go file +var vflag string // -v [y.output] - y.output file +var lflag bool // -l - disable line directives +} + + +/* This comment is the last entry in this file. It must be printed and should be followed by a newline */ diff --git a/src/pkg/go/printer/testdata/comments.x b/src/pkg/go/printer/testdata/comments.x new file mode 100644 index 000000000..ae7729286 --- /dev/null +++ b/src/pkg/go/printer/testdata/comments.x @@ -0,0 +1,56 @@ +// This is a package for testing comment placement by go/printer. +// +package main + +// The SZ struct; it is empty. +type SZ struct{} + +// The S0 struct; no field is exported. +type S0 struct { + // contains filtered or unexported fields +} + +// The S1 struct; some fields are not exported. +type S1 struct { + S0 + A, B, C float // 3 exported fields + D int // 2 unexported fields + // contains filtered or unexported fields +} + +// The S2 struct; all fields are exported. +type S2 struct { + S1 + A, B, C float // 3 exported fields +} + +// The IZ interface; it is empty. +type SZ interface{} + +// The I0 interface; no method is exported. +type I0 interface { + // contains filtered or unexported methods +} + +// The I1 interface; some methods are not exported. +type I1 interface { + I0 + F(x float) float // exported methods + // contains filtered or unexported methods +} + +// The I2 interface; all methods are exported. +type I2 interface { + I0 + F(x float) float // exported method + G(x float) float // exported method +} + +// The S3 struct; all comments except for the last one must appear in the export. +type S3 struct { + // lead comment for F1 + F1 int // line comment for F1 + // lead comment for F2 + F2 int // line comment for F2 + // contains filtered or unexported fields +} diff --git a/src/pkg/go/printer/testdata/declarations.golden b/src/pkg/go/printer/testdata/declarations.golden new file mode 100644 index 000000000..970533e8c --- /dev/null +++ b/src/pkg/go/printer/testdata/declarations.golden @@ -0,0 +1,747 @@ +// Copyright 2009 The Go Authors. All rights reserved. +// Use of this source code is governed by a BSD-style +// license that can be found in the LICENSE file. + +package imports + +import "io" + +import ( + _ "io" +) + +import _ "io" + +import ( + "io" + "io" + "io" +) + +import ( + "io" + aLongRename "io" + + b "io" +) + +import ( + "unrenamed" + renamed "renameMe" + . "io" + _ "io" + "io" + . "os" +) + +// no newlines between consecutive single imports, but +// respect extra line breaks in the source (at most one empty line) +import _ "io" +import _ "io" +import _ "io" + +import _ "os" +import _ "os" +import _ "os" + +import _ "fmt" +import _ "fmt" +import _ "fmt" + +import "foo" // a comment +import "bar" // a comment + +import ( + _ "foo" + // a comment + "bar" + "foo" // a comment + "bar" // a comment +) + +// comments + renames +import ( + "unrenamed" // a comment + renamed "renameMe" + . "io" /* a comment */ + _ "io/ioutil" // a comment + "io" // testing alignment + . "os" + // a comment +) + +// a case that caused problems in the past (comment placement) +import ( + . "fmt" + "io" + "malloc" // for the malloc count test only + "math" + "strings" + "testing" +) + +// more import examples +import ( + "xxx" + "much longer name" // comment + "short name" // comment +) + +import ( + _ "xxx" + "much longer name" // comment +) + +import ( + mymath "math" + "/foo/bar/long_package_path" // a comment +) + +import ( + "package_a" // comment + "package_b" + my_better_c "package_c" // comment + "package_d" // comment + my_e "package_e" // comment + + "package_a" // comment + "package_bb" + "package_ccc" // comment + "package_dddd" // comment +) + +// at least one empty line between declarations of different kind +import _ "io" + +var _ int + +// printing of constant literals +const ( + _ = "foobar" + _ = "a۰۱۸" + _ = "foo६४" + _ = "bar９８７６" + _ = 0 + _ = 1 + _ = 123456789012345678890 + _ = 01234567 + _ = 0xcafebabe + _ = 0. + _ = .0 + _ = 3.14159265 + _ = 1e0 + _ = 1e+100 + _ = 1e-100 + _ = 2.71828e-1000 + _ = 0i + _ = 1i + _ = 012345678901234567889i + _ = 123456789012345678890i + _ = 0.i + _ = .0i + _ = 3.14159265i + _ = 1e0i + _ = 1e+100i + _ = 1e-100i + _ = 2.71828e-1000i + _ = 'a' + _ = '\000' + _ = '\xFF' + _ = '\uff16' + _ = '\U0000ff16' + _ = `foobar` + _ = `foo +--- +--- +bar` +) + +func _() { + type _ int + type _ *int + type _ []int + type _ map[string]int + type _ chan int + type _ func() int + + var _ int + var _ *int + var _ []int + var _ map[string]int + var _ chan int + var _ func() int + + type _ struct{} + type _ *struct{} + type _ []struct{} + type _ map[string]struct{} + type _ chan struct{} + type _ func() struct{} + + type _ interface{} + type _ *interface{} + type _ []interface{} + type _ map[string]interface{} + type _ chan interface{} + type _ func() interface{} + + var _ struct{} + var _ *struct{} + var _ []struct{} + var _ map[string]struct{} + var _ chan struct{} + var _ func() struct{} + + var _ interface{} + var _ *interface{} + var _ []interface{} + var _ map[string]interface{} + var _ chan interface{} + var _ func() interface{} +} + +// don't lose blank lines in grouped declarations +const ( + _ int = 0 + _ float = 1 + + _ string = "foo" + + _ = iota + _ + + // a comment + _ + + _ +) + +type ( + _ int + _ struct{} + + _ interface{} + + // a comment + _ map[string]int +) + +var ( + _ int = 0 + _ float = 1 + + _ string = "foo" + + _ bool + + // a comment + _ bool +) + +// don't lose blank lines in this struct +type _ struct { + String struct { + Str, Len int + } + Slice struct { + Array, Len, Cap int + } + Eface struct { + Typ, Ptr int + } + + UncommonType struct { + Name, PkgPath int + } + CommonType struct { + Size, Hash, Alg, Align, FieldAlign, String, UncommonType int + } + Type struct { + Typ, Ptr int + } + StructField struct { + Name, PkgPath, Typ, Tag, Offset int + } + StructType struct { + Fields int + } + PtrType struct { + Elem int + } + SliceType struct { + Elem int + } + ArrayType struct { + Elem, Len int + } + + Stktop struct { + Stackguard, Stackbase, Gobuf int + } + Gobuf struct { + Sp, Pc, G int + } + G struct { + Stackbase, Sched, Status, Alllink int + } +} + +// no tabs for single or ungrouped decls +func _() { + const xxxxxx = 0 + type x int + var xxx int + var yyyy float = 3.14 + var zzzzz = "bar" + + const ( + xxxxxx = 0 + ) + type ( + x int + ) + var ( + xxx int + ) + var ( + yyyy float = 3.14 + ) + var ( + zzzzz = "bar" + ) +} + +// tabs for multiple or grouped decls +func _() { + // no entry has a type + const ( + zzzzzz = 1 + z = 2 + zzz = 3 + ) + // some entries have a type + const ( + xxxxxx = 1 + x = 2 + xxx = 3 + yyyyyyyy float = iota + yyyy = "bar" + yyy + yy = 2 + ) +} + +func _() { + // no entry has a type + var ( + zzzzzz = 1 + z = 2 + zzz = 3 + ) + // no entry has a value + var ( + _ int + _ float + _ string + + _ int // comment + _ float // comment + _ string // comment + ) + // some entries have a type + var ( + xxxxxx int + x float + xxx string + yyyyyyyy int = 1234 + y float = 3.14 + yyyy = "bar" + yyy string = "foo" + ) + // mixed entries - all comments should be aligned + var ( + a, b, c int + x = 10 + d int // comment + y = 20 // comment + f, ff, fff, ffff int = 0, 1, 2, 3 // comment + ) + // respect original line breaks + var _ = []T{ + T{0x20, "Telugu"}, + } + var _ = []T{ + // respect original line breaks + T{0x20, "Telugu"}, + } +} + +func _() { + type ( + xxxxxx int + x float + xxx string + xxxxx []x + xx struct{} + xxxxxxx struct { + _, _ int + _ float + } + xxxx chan<- string + ) +} + +// alignment of "=" in consecutive lines (extended example from issue 1414) +const ( + umax uint = ^uint(0) // maximum value for a uint + bpu = 1 << (5 + umax>>63) // bits per uint + foo + bar = -1 +) + +// typical enum +const ( + a MyType = iota + abcd + b + c + def +) + +// excerpt from godoc.go +var ( + goroot = flag.String("goroot", runtime.GOROOT(), "Go root directory") + testDir = flag.String("testdir", "", "Go root subdirectory - for testing only (faster startups)") + pkgPath = flag.String("path", "", "additional package directories (colon-separated)") + filter = flag.String("filter", "", "filter file containing permitted package directory paths") + filterMin = flag.Int("filter_minutes", 0, "filter file update interval in minutes; disabled if <= 0") + filterDelay delayTime // actual filter update interval in minutes; usually filterDelay == filterMin, but filterDelay may back off exponentially +) + +// formatting of structs +type _ struct{} + +type _ struct { /* this comment should be visible */ +} + +type _ struct { + // this comment should be visible and properly indented +} + +type _ struct { // this comment must not change indentation + f int + f, ff, fff, ffff int +} + +type _ struct { + string +} + +type _ struct { + string // comment +} + +type _ struct { + string "tag" +} + +type _ struct { + string "tag" // comment +} + +type _ struct { + f int +} + +type _ struct { + f int // comment +} + +type _ struct { + f int "tag" +} + +type _ struct { + f int "tag" // comment +} + +type _ struct { + bool + a, b, c int + int "tag" + ES // comment + float "tag" // comment + f int // comment + f, ff, fff, ffff int // comment + g float "tag" + h float "tag" // comment +} + +type _ struct { + a, b, + c, d int // this line should be indented + u, v, w, x float // this line should be indented + p, q, + r, s float // this line should be indented +} + +// difficult cases +type _ struct { + bool // comment + text []byte // comment +} + +// formatting of interfaces +type EI interface{} + +type _ interface { + EI +} + +type _ interface { + f() + fffff() +} + +type _ interface { + EI + f() + fffffg() +} + +type _ interface { // this comment must not change indentation + EI // here's a comment + f() // no blank between identifier and () + fffff() // no blank between identifier and () + gggggggggggg(x, y, z int) // hurray +} + +// formatting of variable declarations +func _() { + type day struct { + n int + short, long string + } + var ( + Sunday = day{0, "SUN", "Sunday"} + Monday = day{1, "MON", "Monday"} + Tuesday = day{2, "TUE", "Tuesday"} + Wednesday = day{3, "WED", "Wednesday"} + Thursday = day{4, "THU", "Thursday"} + Friday = day{5, "FRI", "Friday"} + Saturday = day{6, "SAT", "Saturday"} + ) +} + +// formatting of multi-line variable declarations +var a1, b1, c1 int // all on one line + +var a2, b2, + c2 int // this line should be indented + +var ( + a3, b3, + c3, d3 int // this line should be indented + a4, b4, c4 int // this line should be indented +) + +func _() { + var privateKey2 = &Block{Type: "RSA PRIVATE KEY", + Headers: map[string]string{}, + Bytes: []uint8{0x30, 0x82, 0x1, 0x3a, 0x2, 0x1, 0x0, 0x2, + 0x41, 0x0, 0xb2, 0x99, 0xf, 0x49, 0xc4, 0x7d, 0xfa, 0x8c, + 0xd4, 0x0, 0xae, 0x6a, 0x4d, 0x1b, 0x8a, 0x3b, 0x6a, 0x13, + 0x64, 0x2b, 0x23, 0xf2, 0x8b, 0x0, 0x3b, 0xfb, 0x97, 0x79, + }, + } +} + +func _() { + var Universe = Scope{ + Names: map[string]*Ident{ + // basic types + "bool": nil, + "byte": nil, + "int8": nil, + "int16": nil, + "int32": nil, + "int64": nil, + "uint8": nil, + "uint16": nil, + "uint32": nil, + "uint64": nil, + "float32": nil, + "float64": nil, + "string": nil, + + // convenience types + "int": nil, + "uint": nil, + "uintptr": nil, + "float": nil, + + // constants + "false": nil, + "true": nil, + "iota": nil, + "nil": nil, + + // functions + "cap": nil, + "len": nil, + "new": nil, + "make": nil, + "panic": nil, + "panicln": nil, + "print": nil, + "println": nil, + }, + } +} + +// alignment of map composite entries +var _ = map[int]int{ + // small key sizes: always align even if size ratios are large + a: a, + abcdefghabcdefgh: a, + ab: a, + abc: a, + abcdefgabcdefg: a, + abcd: a, + abcde: a, + abcdef: a, + + // mixed key sizes: align when key sizes change within accepted ratio + abcdefgh: a, + abcdefghabcdefg: a, + abcdefghij: a, + abcdefghijabcdefghijabcdefghijabcdefghijabcdefghijabcdefghijabcdefghij: a, // outlier - do not align with previous line + abcdefghijabcdefghijabcdefghijabcdefghijabcdefghijabcdefghij: a, // align with previous line + + ab: a, // do not align with previous line + abcde: a, // align with previous line +} + +func _() { + var _ = T{ + a, // must introduce trailing comma + } +} + +// formatting of function results +func _() func() {} +func _() func(int) { return nil } +func _() func(int) int { return nil } +func _() func(int) func(int) func() { return nil } + +// formatting of consecutive single-line functions +func _() {} +func _() {} +func _() {} + +func _() {} // an empty line before this function +func _() {} +func _() {} + +func _() { f(1, 2, 3) } +func _(x int) int { y := x; return y + 1 } +func _() int { type T struct{}; var x T; return x } + +// these must remain multi-line since they are multi-line in the source +func _() { + f(1, 2, 3) +} +func _(x int) int { + y := x + return y + 1 +} +func _() int { + type T struct{} + var x T + return x +} + +// making function declarations safe for new semicolon rules +func _() { /* multi-line func because of comment */ +} + +func _() { + /* multi-line func because block is on multiple lines */ +} + +// ellipsis parameters +func _(...int) +func _(...*int) +func _(...[]int) +func _(...struct{}) +func _(bool, ...interface{}) +func _(bool, ...func()) +func _(bool, ...func(...int)) +func _(bool, ...map[string]int) +func _(bool, ...chan int) + +func _(b bool, x ...int) +func _(b bool, x ...*int) +func _(b bool, x ...[]int) +func _(b bool, x ...struct{}) +func _(x ...interface{}) +func _(x ...func()) +func _(x ...func(...int)) +func _(x ...map[string]int) +func _(x ...chan int) + +// these parameter lists must remain multi-line since they are multi-line in the source +func _(bool, +int) { +} +func _(x bool, +y int) { +} +func _(x, +y bool) { +} +func _(bool, // comment +int) { +} +func _(x bool, // comment +y int) { +} +func _(x, // comment +y bool) { +} +func _(bool, // comment +// comment +int) { +} +func _(x bool, // comment +// comment +y int) { +} +func _(x, // comment +// comment +y bool) { +} +func _(bool, +// comment +int) { +} +func _(x bool, +// comment +y int) { +} +func _(x, +// comment +y bool) { +} +func _(x, // comment +y, // comment +z bool) { +} +func _(x, // comment +y, // comment +z bool) { +} +func _(x int, // comment +y float, // comment +z bool) { +} diff --git a/src/pkg/go/printer/testdata/declarations.input b/src/pkg/go/printer/testdata/declarations.input new file mode 100644 index 000000000..c6134096b --- /dev/null +++ b/src/pkg/go/printer/testdata/declarations.input @@ -0,0 +1,757 @@ +// Copyright 2009 The Go Authors. All rights reserved. +// Use of this source code is governed by a BSD-style +// license that can be found in the LICENSE file. + +package imports + +import "io" + +import ( + _ "io" +) + +import _ "io" + +import ( + "io" + "io" + "io" +) + +import ( + "io" + aLongRename "io" + + b "io" +) + +import ( + "unrenamed" + renamed "renameMe" + . "io" + _ "io" + "io" + . "os" +) + +// no newlines between consecutive single imports, but +// respect extra line breaks in the source (at most one empty line) +import _ "io" +import _ "io" +import _ "io" + +import _ "os" +import _ "os" +import _ "os" + + +import _ "fmt" +import _ "fmt" +import _ "fmt" + +import "foo" // a comment +import "bar" // a comment + +import ( + _ "foo" + // a comment + "bar" + "foo" // a comment + "bar" // a comment +) + +// comments + renames +import ( + "unrenamed" // a comment + renamed "renameMe" + . "io" /* a comment */ + _ "io/ioutil" // a comment + "io" // testing alignment + . "os" + // a comment +) + +// a case that caused problems in the past (comment placement) +import ( + . "fmt" + "io" + "malloc" // for the malloc count test only + "math" + "strings" + "testing" +) + +// more import examples +import ( + "xxx" + "much longer name" // comment + "short name" // comment +) + +import ( + _ "xxx" + "much longer name" // comment +) + +import ( + mymath "math" + "/foo/bar/long_package_path" // a comment +) + +import ( + "package_a" // comment + "package_b" + my_better_c "package_c" // comment + "package_d" // comment + my_e "package_e" // comment + + "package_a" // comment + "package_bb" + "package_ccc" // comment + "package_dddd" // comment +) + +// at least one empty line between declarations of different kind +import _ "io" +var _ int + + +// printing of constant literals +const ( + _ = "foobar" + _ = "a۰۱۸" + _ = "foo६४" + _ = "bar９８７６" + _ = 0 + _ = 1 + _ = 123456789012345678890 + _ = 01234567 + _ = 0xcafebabe + _ = 0. + _ = .0 + _ = 3.14159265 + _ = 1e0 + _ = 1e+100 + _ = 1e-100 + _ = 2.71828e-1000 + _ = 0i + _ = 1i + _ = 012345678901234567889i + _ = 123456789012345678890i + _ = 0.i + _ = .0i + _ = 3.14159265i + _ = 1e0i + _ = 1e+100i + _ = 1e-100i + _ = 2.71828e-1000i + _ = 'a' + _ = '\000' + _ = '\xFF' + _ = '\uff16' + _ = '\U0000ff16' + _ = `foobar` + _ = `foo +--- +--- +bar` +) + + +func _() { + type _ int + type _ *int + type _ []int + type _ map[string]int + type _ chan int + type _ func() int + + var _ int + var _ *int + var _ []int + var _ map[string]int + var _ chan int + var _ func() int + + type _ struct{} + type _ *struct{} + type _ []struct{} + type _ map[string]struct{} + type _ chan struct{} + type _ func() struct{} + + type _ interface{} + type _ *interface{} + type _ []interface{} + type _ map[string]interface{} + type _ chan interface{} + type _ func() interface{} + + var _ struct{} + var _ *struct{} + var _ []struct{} + var _ map[string]struct{} + var _ chan struct{} + var _ func() struct{} + + var _ interface{} + var _ *interface{} + var _ []interface{} + var _ map[string]interface{} + var _ chan interface{} + var _ func() interface{} +} + + +// don't lose blank lines in grouped declarations +const ( + _ int = 0 + _ float = 1 + + _ string = "foo" + + _ = iota + _ + + // a comment + _ + + _ +) + + +type ( + _ int + _ struct {} + + _ interface{} + + // a comment + _ map[string]int +) + + +var ( + _ int = 0 + _ float = 1 + + _ string = "foo" + + _ bool + + // a comment + _ bool +) + + +// don't lose blank lines in this struct +type _ struct { + String struct { + Str, Len int + } + Slice struct { + Array, Len, Cap int + } + Eface struct { + Typ, Ptr int + } + + UncommonType struct { + Name, PkgPath int + } + CommonType struct { + Size, Hash, Alg, Align, FieldAlign, String, UncommonType int + } + Type struct { + Typ, Ptr int + } + StructField struct { + Name, PkgPath, Typ, Tag, Offset int + } + StructType struct { + Fields int + } + PtrType struct { + Elem int + } + SliceType struct { + Elem int + } + ArrayType struct { + Elem, Len int + } + + Stktop struct { + Stackguard, Stackbase, Gobuf int + } + Gobuf struct { + Sp, Pc, G int + } + G struct { + Stackbase, Sched, Status, Alllink int + } +} + + +// no tabs for single or ungrouped decls +func _() { + const xxxxxx = 0 + type x int + var xxx int + var yyyy float = 3.14 + var zzzzz = "bar" + + const ( + xxxxxx = 0 + ) + type ( + x int + ) + var ( + xxx int + ) + var ( + yyyy float = 3.14 + ) + var ( + zzzzz = "bar" + ) +} + +// tabs for multiple or grouped decls +func _() { + // no entry has a type + const ( + zzzzzz = 1 + z = 2 + zzz = 3 + ) + // some entries have a type + const ( + xxxxxx = 1 + x = 2 + xxx = 3 + yyyyyyyy float = iota + yyyy = "bar" + yyy + yy = 2 + ) +} + +func _() { + // no entry has a type + var ( + zzzzzz = 1 + z = 2 + zzz = 3 + ) + // no entry has a value + var ( + _ int + _ float + _ string + + _ int // comment + _ float // comment + _ string // comment + ) + // some entries have a type + var ( + xxxxxx int + x float + xxx string + yyyyyyyy int = 1234 + y float = 3.14 + yyyy = "bar" + yyy string = "foo" + ) + // mixed entries - all comments should be aligned + var ( + a, b, c int + x = 10 + d int // comment + y = 20 // comment + f, ff, fff, ffff int = 0, 1, 2, 3 // comment + ) + // respect original line breaks + var _ = []T { + T{0x20, "Telugu"}, + } + var _ = []T { + // respect original line breaks + T{0x20, "Telugu"}, + } +} + +func _() { + type ( + xxxxxx int + x float + xxx string + xxxxx []x + xx struct{} + xxxxxxx struct { + _, _ int + _ float + } + xxxx chan<- string + ) +} + +// alignment of "=" in consecutive lines (extended example from issue 1414) +const ( + umax uint = ^uint(0) // maximum value for a uint + bpu = 1 << (5 + umax>>63) // bits per uint + foo + bar = -1 +) + +// typical enum +const ( + a MyType = iota + abcd + b + c + def +) + +// excerpt from godoc.go +var ( + goroot = flag.String("goroot", runtime.GOROOT(), "Go root directory") + testDir = flag.String("testdir", "", "Go root subdirectory - for testing only (faster startups)") + pkgPath = flag.String("path", "", "additional package directories (colon-separated)") + filter = flag.String("filter", "", "filter file containing permitted package directory paths") + filterMin = flag.Int("filter_minutes", 0, "filter file update interval in minutes; disabled if <= 0") + filterDelay delayTime // actual filter update interval in minutes; usually filterDelay == filterMin, but filterDelay may back off exponentially +) + + +// formatting of structs +type _ struct{} + +type _ struct{ /* this comment should be visible */ } + +type _ struct{ + // this comment should be visible and properly indented +} + +type _ struct { // this comment must not change indentation + f int + f, ff, fff, ffff int +} + +type _ struct { + string +} + +type _ struct { + string // comment +} + +type _ struct { + string "tag" +} + +type _ struct { + string "tag" // comment +} + +type _ struct { + f int +} + +type _ struct { + f int // comment +} + +type _ struct { + f int "tag" +} + +type _ struct { + f int "tag" // comment +} + +type _ struct { + bool + a, b, c int + int "tag" + ES // comment + float "tag" // comment + f int // comment + f, ff, fff, ffff int // comment + g float "tag" + h float "tag" // comment +} + +type _ struct { a, b, +c, d int // this line should be indented +u, v, w, x float // this line should be indented +p, q, +r, s float // this line should be indented +} + + +// difficult cases +type _ struct { + bool // comment + text []byte // comment +} + + +// formatting of interfaces +type EI interface{} + +type _ interface { + EI +} + +type _ interface { + f() + fffff() +} + +type _ interface { + EI + f() + fffffg() +} + +type _ interface { // this comment must not change indentation + EI // here's a comment + f() // no blank between identifier and () + fffff() // no blank between identifier and () + gggggggggggg(x, y, z int) () // hurray +} + + +// formatting of variable declarations +func _() { + type day struct { n int; short, long string } + var ( + Sunday = day{ 0, "SUN", "Sunday" } + Monday = day{ 1, "MON", "Monday" } + Tuesday = day{ 2, "TUE", "Tuesday" } + Wednesday = day{ 3, "WED", "Wednesday" } + Thursday = day{ 4, "THU", "Thursday" } + Friday = day{ 5, "FRI", "Friday" } + Saturday = day{ 6, "SAT", "Saturday" } + ) +} + + +// formatting of multi-line variable declarations +var a1, b1, c1 int // all on one line + +var a2, b2, +c2 int // this line should be indented + +var (a3, b3, +c3, d3 int // this line should be indented +a4, b4, c4 int // this line should be indented +) + + +func _() { + var privateKey2 = &Block{Type: "RSA PRIVATE KEY", + Headers: map[string]string{}, + Bytes: []uint8{0x30, 0x82, 0x1, 0x3a, 0x2, 0x1, 0x0, 0x2, + 0x41, 0x0, 0xb2, 0x99, 0xf, 0x49, 0xc4, 0x7d, 0xfa, 0x8c, + 0xd4, 0x0, 0xae, 0x6a, 0x4d, 0x1b, 0x8a, 0x3b, 0x6a, 0x13, + 0x64, 0x2b, 0x23, 0xf2, 0x8b, 0x0, 0x3b, 0xfb, 0x97, 0x79, + }, + } +} + + +func _() { + var Universe = Scope { + Names: map[string]*Ident { + // basic types + "bool": nil, + "byte": nil, + "int8": nil, + "int16": nil, + "int32": nil, + "int64": nil, + "uint8": nil, + "uint16": nil, + "uint32": nil, + "uint64": nil, + "float32": nil, + "float64": nil, + "string": nil, + + // convenience types + "int": nil, + "uint": nil, + "uintptr": nil, + "float": nil, + + // constants + "false": nil, + "true": nil, + "iota": nil, + "nil": nil, + + // functions + "cap": nil, + "len": nil, + "new": nil, + "make": nil, + "panic": nil, + "panicln": nil, + "print": nil, + "println": nil, + }, + } +} + + +// alignment of map composite entries +var _ = map[int]int{ + // small key sizes: always align even if size ratios are large + a: a, + abcdefghabcdefgh: a, + ab: a, + abc: a, + abcdefgabcdefg: a, + abcd: a, + abcde: a, + abcdef: a, + + // mixed key sizes: align when key sizes change within accepted ratio + abcdefgh: a, + abcdefghabcdefg: a, + abcdefghij: a, + abcdefghijabcdefghijabcdefghijabcdefghijabcdefghijabcdefghijabcdefghij: a, // outlier - do not align with previous line + abcdefghijabcdefghijabcdefghijabcdefghijabcdefghijabcdefghij: a, // align with previous line + + ab: a, // do not align with previous line + abcde: a, // align with previous line +} + + +func _() { + var _ = T{ + a, // must introduce trailing comma + } +} + + +// formatting of function results +func _() func() {} +func _() func(int) { return nil } +func _() func(int) int { return nil } +func _() func(int) func(int) func() { return nil } + + +// formatting of consecutive single-line functions +func _() {} +func _() {} +func _() {} + +func _() {} // an empty line before this function +func _() {} +func _() {} + +func _() { f(1, 2, 3) } +func _(x int) int { y := x; return y+1 } +func _() int { type T struct{}; var x T; return x } + +// these must remain multi-line since they are multi-line in the source +func _() { + f(1, 2, 3) +} +func _(x int) int { + y := x; return y+1 +} +func _() int { + type T struct{}; var x T; return x +} + + +// making function declarations safe for new semicolon rules +func _() { /* multi-line func because of comment */ } + +func _() { +/* multi-line func because block is on multiple lines */ } + + +// ellipsis parameters +func _(...int) +func _(...*int) +func _(...[]int) +func _(...struct{}) +func _(bool, ...interface{}) +func _(bool, ...func()) +func _(bool, ...func(...int)) +func _(bool, ...map[string]int) +func _(bool, ...chan int) + +func _(b bool, x ...int) +func _(b bool, x ...*int) +func _(b bool, x ...[]int) +func _(b bool, x ...struct{}) +func _(x ...interface{}) +func _(x ...func()) +func _(x ...func(...int)) +func _(x ...map[string]int) +func _(x ...chan int) + + +// these parameter lists must remain multi-line since they are multi-line in the source +func _(bool, +int) { +} +func _(x bool, +y int) { +} +func _(x, +y bool) { +} +func _(bool, // comment +int) { +} +func _(x bool, // comment +y int) { +} +func _(x, // comment +y bool) { +} +func _(bool, // comment +// comment +int) { +} +func _(x bool, // comment +// comment +y int) { +} +func _(x, // comment +// comment +y bool) { +} +func _(bool, +// comment +int) { +} +func _(x bool, +// comment +y int) { +} +func _(x, +// comment +y bool) { +} +func _(x, // comment +y,// comment +z bool) { +} +func _(x, // comment + y,// comment + z bool) { +} +func _(x int, // comment + y float, // comment + z bool) { +} diff --git a/src/pkg/go/printer/testdata/empty.golden b/src/pkg/go/printer/testdata/empty.golden new file mode 100644 index 000000000..a055f4758 --- /dev/null +++ b/src/pkg/go/printer/testdata/empty.golden @@ -0,0 +1,5 @@ +// a comment at the beginning of the file + +package empty + +// a comment at the end of the file diff --git a/src/pkg/go/printer/testdata/empty.input b/src/pkg/go/printer/testdata/empty.input new file mode 100644 index 000000000..a055f4758 --- /dev/null +++ b/src/pkg/go/printer/testdata/empty.input @@ -0,0 +1,5 @@ +// a comment at the beginning of the file + +package empty + +// a comment at the end of the file diff --git a/src/pkg/go/printer/testdata/expressions.golden b/src/pkg/go/printer/testdata/expressions.golden new file mode 100644 index 000000000..d0cf24ad6 --- /dev/null +++ b/src/pkg/go/printer/testdata/expressions.golden @@ -0,0 +1,627 @@ +// Copyright 2009 The Go Authors. All rights reserved. +// Use of this source code is governed by a BSD-style +// license that can be found in the LICENSE file. + +package expressions + +type T struct { + x, y, z int +} + +var ( + a, b, c, d, e int + under_bar int + longIdentifier1, longIdentifier2, longIdentifier3 int + t0, t1, t2 T + s string + p *int +) + +func _() { + // no spaces around simple or parenthesized expressions + _ = (a + 0) + _ = a + b + _ = a + b + c + _ = a + b - c + _ = a - b - c + _ = a + (b * c) + _ = a + (b / c) + _ = a - (b % c) + _ = 1 + a + _ = a + 1 + _ = a + b + 1 + _ = s[a] + _ = s[a:] + _ = s[:b] + _ = s[1:2] + _ = s[a:b] + _ = s[0:len(s)] + _ = s[0] << 1 + _ = (s[0] << 1) & 0xf + _ = s[0]<<2 | s[1]>>4 + _ = "foo" + s + _ = s + "foo" + _ = 'a' + 'b' + _ = len(s) / 2 + _ = len(t0.x) / a + + // spaces around expressions of different precedence or expressions containing spaces + _ = a + -b + _ = a - ^b + _ = a / *p + _ = a + b*c + _ = 1 + b*c + _ = a + 2*c + _ = a + c*2 + _ = 1 + 2*3 + _ = s[1 : 2*3] + _ = s[a : b-c] + _ = s[0:] + _ = s[a+b] + _ = s[:b-c] + _ = s[a+b:] + _ = a[a<<b+1] + _ = a[a<<b+1:] + _ = s[a+b : len(s)] + _ = s[len(s):-a] + _ = s[a : len(s)+1] + _ = s[a:len(s)+1] + s + + // spaces around operators with equal or lower precedence than comparisons + _ = a == b + _ = a != b + _ = a > b + _ = a >= b + _ = a < b + _ = a <= b + _ = a < b && c > d + _ = a < b || c > d + + // spaces around "long" operands + _ = a + longIdentifier1 + _ = longIdentifier1 + a + _ = longIdentifier1 + longIdentifier2*longIdentifier3 + _ = s + "a longer string" + + // some selected cases + _ = a + t0.x + _ = a + t0.x + t1.x*t2.x + _ = a + b + c + d + e + 2*3 + _ = a + b + c + 2*3 + d + e + _ = (a + b + c) * 2 + _ = a - b + c - d + (a + b + c) + d&e + _ = under_bar - 1 + _ = Open(dpath+"/file", O_WRONLY|O_CREAT, 0666) + _ = int(c0&_Mask4)<<18 | int(c1&_Maskx)<<12 | int(c2&_Maskx)<<6 | int(c3&_Maskx) + + // the parser does not restrict expressions that may appear as statements + true + 42 + "foo" + x + (x) + a + b + a + b + c + a + (b * c) + a + (b / c) + 1 + a + a + 1 + s[a] + x << 1 + (s[0] << 1) & 0xf + "foo" + s + x == y + x < y || z > 42 +} + +func _() { + _ = a + b + _ = a + b + c + _ = a + b*c + _ = a + (b * c) + _ = (a + b) * c + _ = a + (b * c * d) + _ = a + (b*c + d) + + _ = 1 << x + _ = -1 << x + _ = 1<<x - 1 + _ = -1<<x - 1 + + _ = f(a + b) + _ = f(a + b + c) + _ = f(a + b*c) + _ = f(a + (b * c)) + _ = f(1<<x-1, 1<<x-2) + + _ = 1<<d.logWindowSize - 1 + + buf = make(x, 2*cap(b.buf)+n) + + dst[i*3+2] = dbuf[0] << 2 + dst[i*3+2] = dbuf[0]<<2 | dbuf[1]>>4 + + b.buf = b.buf[0 : b.off+m+n] + b.buf = b.buf[0 : b.off+m*n] + f(b.buf[0 : b.off+m+n]) + + signed += ' ' * 8 + tw.octal(header[148:155], chksum) + + _ = x > 0 && i >= 0 + + x1, x0 := x>>w2, x&m2 + z0 = t1<<w2 + t0 + z1 = (t1 + t0>>w2) >> w2 + q1, r1 := x1/d1, x1%d1 + r1 = r1*b2 | x0>>w2 + x1 = (x1 << z) | (x0 >> (uint(w) - z)) + x1 = x1<<z | x0>>(uint(w)-z) + + _ = buf[0 : len(buf)+1] + _ = buf[0 : n+1] + + a, b = b, a + a = b + c + a = b*c + d + _ = a*b + c + _ = a - b - c + _ = a - (b - c) + _ = a - b*c + _ = a - (b * c) + _ = a * b / c + _ = a / *b + _ = x[a|^b] + _ = x[a / *b] + _ = a & ^b + _ = a + +b + _ = a - -b + _ = x[a*-b] + _ = x[a + +b] + _ = x ^ y ^ z + _ = b[a>>24] ^ b[(a>>16)&0xFF] ^ b[(a>>8)&0xFF] ^ b[a&0xFF] + _ = len(longVariableName) * 2 + + _ = token(matchType + xlength<<lengthShift + xoffset) +} + +func f(x int, args ...int) { + f(0, args...) + f(1, args) + f(2, args[0]) + + // make sure syntactically legal code remains syntactically legal + f(3, 42 ...) // a blank must remain between 42 and ... + f(4, 42....) + f(5, 42....) + f(6, 42.0...) + f(7, 42.0...) + f(8, .42...) + f(9, .42...) + f(10, 42e0...) + f(11, 42e0...) + + _ = 42 .x // a blank must remain between 42 and .x + _ = 42..x + _ = 42..x + _ = 42.0.x + _ = 42.0.x + _ = .42.x + _ = .42.x + _ = 42e0.x + _ = 42e0.x + + // a blank must remain between the binary operator and the 2nd operand + _ = x / *y + _ = x < -1 + _ = x < <-1 + _ = x + +1 + _ = x - -1 + _ = x & &x + _ = x & ^x + + _ = f(x / *y, x < -1, x < <-1, x + +1, x - -1, x & &x, x & ^x) +} + +func _() { + _ = T{} + _ = struct{}{} + _ = [10]T{} + _ = [...]T{} + _ = []T{} + _ = map[int]T{} +} + +// one-line structs/interfaces in composite literals (up to a threshold) +func _() { + _ = struct{}{} + _ = struct{ x int }{0} + _ = struct{ x, y, z int }{0, 1, 2} + _ = struct{ int }{0} + _ = struct{ s struct{ int } }{struct{ int }{0}} +} + +func _() { + // do not modify literals + _ = "tab1 tab2 tab3 end" // string contains 3 tabs + _ = "tab1 tab2 tab3 end" // same string with 3 blanks - may be unaligned because editors see tabs in strings + _ = "" // this comment should be aligned with the one on the previous line + _ = `` + _ = ` +` + _ = `foo + bar` + _ = `three spaces before the end of the line starting here: +they must not be removed` +} + +func _() { + // smart handling of indentation for multi-line raw strings + var _ = `` + var _ = `foo` + var _ = `foo +bar` + + var _ = `` + var _ = `foo` + var _ = + // the next line should remain indented + `foo +bar` + + var _ = // comment + `` + var _ = // comment + `foo` + var _ = // comment + // the next line should remain indented + `foo +bar` + + var _ = /* comment */ `` + var _ = /* comment */ `foo` + var _ = /* comment */ `foo +bar` + + var _ = /* comment */ + `` + var _ = /* comment */ + `foo` + var _ = /* comment */ + // the next line should remain indented + `foo +bar` + + var board = []int( + `........... +........... +....●●●.... +....●●●.... +..●●●●●●●.. +..●●●○●●●.. +..●●●●●●●.. +....●●●.... +....●●●.... +........... +........... +`) + + var state = S{ + "foo", + // the next line should remain indented + `........... +........... +....●●●.... +....●●●.... +..●●●●●●●.. +..●●●○●●●.. +..●●●●●●●.. +....●●●.... +....●●●.... +........... +........... +`, + "bar", + } +} + +func _() { + // one-line function literals (body is on a single line) + _ = func() {} + _ = func() int { return 0 } + _ = func(x, y int) bool { m := (x + y) / 2; return m < 0 } + + // multi-line function literals (body is not on one line) + _ = func() { + } + _ = func() int { + return 0 + } + _ = func(x, y int) bool { + m := (x + y) / 2 + return x < y + } + + f(func() { + }) + f(func() int { + return 0 + }) + f(func(x, y int) bool { + m := (x + y) / 2 + return x < y + }) +} + +func _() { + _ = [][]int{ + []int{1}, + []int{1, 2}, + []int{1, 2, 3}, + } + _ = [][]int{ + {1}, + []int{1, 2}, + []int{1, 2, 3}, + } + _ = [][]int{ + {1}, + {1, 2}, + {1, 2, 3}, + } + _ = [][]int{{1}, {1, 2}, {1, 2, 3}} +} + +// various multi-line expressions +func _() { + // do not add extra indentation to multi-line string lists + _ = "foo" + "bar" + _ = "foo" + + "bar" + + "bah" + _ = []string{ + "abc" + + "def", + "foo" + + "bar", + } +} + +const _ = F1 + + `string = "%s";` + + `ptr = *;` + + `datafmt.T2 = s ["-" p "-"];` + +const _ = `datafmt "datafmt";` + + `default = "%v";` + + `array = *;` + + `datafmt.T3 = s {" " a a / ","};` + +const _ = `datafmt "datafmt";` + + `default = "%v";` + + `array = *;` + + `datafmt.T3 = s {" " a a / ","};` + +func _() { + _ = F1 + + `string = "%s";` + + `ptr = *;` + + `datafmt.T2 = s ["-" p "-"];` + + _ = + `datafmt "datafmt";` + + `default = "%v";` + + `array = *;` + + `datafmt.T3 = s {" " a a / ","};` + + _ = `datafmt "datafmt";` + + `default = "%v";` + + `array = *;` + + `datafmt.T3 = s {" " a a / ","};` +} + +func _() { + // respect source lines in multi-line expressions + _ = a + + b + + c + _ = a < b || + b < a + _ = "933262154439441526816992388562667004907159682643816214685929" + + "638952175999932299156089414639761565182862536979208272237582" + + "51185210916864000000000000000000000000" // 100! + _ = "170141183460469231731687303715884105727" // prime +} + +// Alignment after overlong lines +const ( + _ = "991" + _ = "2432902008176640000" // 20! + _ = "933262154439441526816992388562667004907159682643816214685929" + + "638952175999932299156089414639761565182862536979208272237582" + + "51185210916864000000000000000000000000" // 100! + _ = "170141183460469231731687303715884105727" // prime +) + +// Correct placement of operators and comments in multi-line expressions +func _() { + _ = a + // comment + b + // comment + c + _ = "a" + + "b" + // comment + "c" + _ = "ba0408" + "7265717569726564" // field 71, encoding 2, string "required" +} + +// Correct placement of terminating comma/closing parentheses in multi-line calls. +func _() { + f(1, + 2, + 3) + f(1, + 2, + 3, + ) + f(1, + 2, + 3) // comment + f(1, + 2, + 3, // comment + ) + f(1, + 2, + 3) // comment + f(1, + 2, + 3, // comment + ) +} + +// Align comments in multi-line lists of single-line expressions. +var txpix = [NCOL]draw.Color{ + draw.Yellow, // yellow + draw.Cyan, // cyan + draw.Green, // lime green + draw.GreyBlue, // slate + draw.Red, /* red */ + draw.GreyGreen, /* olive green */ + draw.Blue, /* blue */ + draw.Color(0xFF55AAFF), /* pink */ + draw.Color(0xFFAAFFFF), /* lavender */ + draw.Color(0xBB005DFF), /* maroon */ +} + +func same(t, u *Time) bool { + // respect source lines in multi-line expressions + return t.Year == u.Year && + t.Month == u.Month && + t.Day == u.Day && + t.Hour == u.Hour && + t.Minute == u.Minute && + t.Second == u.Second && + t.Weekday == u.Weekday && + t.ZoneOffset == u.ZoneOffset && + t.Zone == u.Zone +} + +func (p *parser) charClass() { + // respect source lines in multi-line expressions + if cc.negate && len(cc.ranges) == 2 && + cc.ranges[0] == '\n' && cc.ranges[1] == '\n' { + nl := new(_NotNl) + p.re.add(nl) + } +} + +func addState(s []state, inst instr, match []int) { + // handle comments correctly in multi-line expressions + for i := 0; i < l; i++ { + if s[i].inst.index() == index && // same instruction + s[i].match[0] < pos { // earlier match already going; leftmost wins + return s + } + } +} + +func (self *T) foo(x int) *T { return self } + +func _() { module.Func1().Func2() } + +func _() { + _ = new(T). + foo(1). + foo(2). + foo(3) + + _ = new(T). + foo(1). + foo(2). // inline comments + foo(3) + + _ = new(T).foo(1).foo(2).foo(3) + + // handle multiline argument list correctly + _ = new(T). + foo( + 1). + foo(2) + + _ = new(T).foo( + 1).foo(2) + + _ = Array[3+ + 4] + + _ = Method(1, 2, + 3) + + _ = new(T). + foo(). + bar().(*Type) + + _ = new(T). + foo(). + bar().(*Type). + baz() + + _ = new(T). + foo(). + bar()["idx"] + + _ = new(T). + foo(). + bar()["idx"]. + baz() + + _ = new(T). + foo(). + bar()[1:2] + + _ = new(T). + foo(). + bar()[1:2]. + baz() + + _ = new(T). + Field. + Array[3+ + 4]. + Table["foo"]. + Blob.(*Type). + Slices[1:4]. + Method(1, 2, + 3). + Thingy + + _ = a.b.c + _ = a. + b. + c + _ = a.b().c + _ = a. + b(). + c + _ = a.b[0].c + _ = a. + b[0]. + c + _ = a.b[0:].c + _ = a. + b[0:]. + c + _ = a.b.(T).c + _ = a. + b.(T). + c +} + +// Don't introduce extra newlines in strangely formatted expression lists. +func f() { + // os.Open parameters should remain on two lines + if writer, err = os.Open(outfile, s.O_WRONLY|os.O_CREATE| + os.O_TRUNC, 0666); err != nil { + log.Fatal(err) + } +} diff --git a/src/pkg/go/printer/testdata/expressions.input b/src/pkg/go/printer/testdata/expressions.input new file mode 100644 index 000000000..d11314983 --- /dev/null +++ b/src/pkg/go/printer/testdata/expressions.input @@ -0,0 +1,656 @@ +// Copyright 2009 The Go Authors. All rights reserved. +// Use of this source code is governed by a BSD-style +// license that can be found in the LICENSE file. + +package expressions + +type T struct { + x, y, z int +} + +var ( + a, b, c, d, e int + under_bar int + longIdentifier1, longIdentifier2, longIdentifier3 int + t0, t1, t2 T + s string + p *int +) + + +func _() { + // no spaces around simple or parenthesized expressions + _ = (a+0) + _ = a+b + _ = a+b+c + _ = a+b-c + _ = a-b-c + _ = a+(b*c) + _ = a+(b/c) + _ = a-(b%c) + _ = 1+a + _ = a+1 + _ = a+b+1 + _ = s[a] + _ = s[a:] + _ = s[:b] + _ = s[1:2] + _ = s[a:b] + _ = s[0:len(s)] + _ = s[0]<<1 + _ = (s[0]<<1)&0xf + _ = s[0] << 2 | s[1] >> 4 + _ = "foo"+s + _ = s+"foo" + _ = 'a'+'b' + _ = len(s)/2 + _ = len(t0.x)/a + + // spaces around expressions of different precedence or expressions containing spaces + _ = a + -b + _ = a - ^b + _ = a / *p + _ = a + b*c + _ = 1 + b*c + _ = a + 2*c + _ = a + c*2 + _ = 1 + 2*3 + _ = s[1 : 2*3] + _ = s[a : b-c] + _ = s[0:] + _ = s[a+b] + _ = s[: b-c] + _ = s[a+b :] + _ = a[a<<b+1] + _ = a[a<<b+1 :] + _ = s[a+b : len(s)] + _ = s[len(s) : -a] + _ = s[a : len(s)+1] + _ = s[a : len(s)+1]+s + + // spaces around operators with equal or lower precedence than comparisons + _ = a == b + _ = a != b + _ = a > b + _ = a >= b + _ = a < b + _ = a <= b + _ = a < b && c > d + _ = a < b || c > d + + // spaces around "long" operands + _ = a + longIdentifier1 + _ = longIdentifier1 + a + _ = longIdentifier1 + longIdentifier2 * longIdentifier3 + _ = s + "a longer string" + + // some selected cases + _ = a + t0.x + _ = a + t0.x + t1.x * t2.x + _ = a + b + c + d + e + 2*3 + _ = a + b + c + 2*3 + d + e + _ = (a+b+c)*2 + _ = a - b + c - d + (a+b+c) + d&e + _ = under_bar-1 + _ = Open(dpath + "/file", O_WRONLY | O_CREAT, 0666) + _ = int(c0&_Mask4)<<18 | int(c1&_Maskx)<<12 | int(c2&_Maskx)<<6 | int(c3&_Maskx) + + // the parser does not restrict expressions that may appear as statements + true + 42 + "foo" + x + (x) + a+b + a+b+c + a+(b*c) + a+(b/c) + 1+a + a+1 + s[a] + x<<1 + (s[0]<<1)&0xf + "foo"+s + x == y + x < y || z > 42 +} + + +func _() { + _ = a+b + _ = a+b+c + _ = a+b*c + _ = a+(b*c) + _ = (a+b)*c + _ = a+(b*c*d) + _ = a+(b*c+d) + + _ = 1<<x + _ = -1<<x + _ = 1<<x-1 + _ = -1<<x-1 + + _ = f(a+b) + _ = f(a+b+c) + _ = f(a+b*c) + _ = f(a+(b*c)) + _ = f(1<<x-1, 1<<x-2) + + _ = 1<<d.logWindowSize-1 + + buf = make(x, 2*cap(b.buf) + n) + + dst[i*3+2] = dbuf[0]<<2 + dst[i*3+2] = dbuf[0]<<2 | dbuf[1]>>4 + + b.buf = b.buf[0:b.off+m+n] + b.buf = b.buf[0:b.off+m*n] + f(b.buf[0:b.off+m+n]) + + signed += ' '*8 + tw.octal(header[148:155], chksum) + + _ = x > 0 && i >= 0 + + x1, x0 := x>>w2, x&m2 + z0 = t1<<w2+t0 + z1 = (t1+t0>>w2)>>w2 + q1, r1 := x1/d1, x1%d1 + r1 = r1*b2 | x0>>w2 + x1 = (x1<<z)|(x0>>(uint(w)-z)) + x1 = x1<<z | x0>>(uint(w)-z) + + _ = buf[0:len(buf)+1] + _ = buf[0:n+1] + + a,b = b,a + a = b+c + a = b*c+d + _ = a*b+c + _ = a-b-c + _ = a-(b-c) + _ = a-b*c + _ = a-(b*c) + _ = a*b/c + _ = a/ *b + _ = x[a|^b] + _ = x[a/ *b] + _ = a& ^b + _ = a+ +b + _ = a- -b + _ = x[a*-b] + _ = x[a+ +b] + _ = x^y^z + _ = b[a>>24] ^ b[(a>>16)&0xFF] ^ b[(a>>8)&0xFF] ^ b[a&0xFF] + _ = len(longVariableName)*2 + + _ = token(matchType + xlength<<lengthShift + xoffset) +} + + +func f(x int, args ...int) { + f(0, args...) + f(1, args) + f(2, args[0]) + + // make sure syntactically legal code remains syntactically legal + f(3, 42 ...) // a blank must remain between 42 and ... + f(4, 42. ...) + f(5, 42....) + f(6, 42.0 ...) + f(7, 42.0...) + f(8, .42 ...) + f(9, .42...) + f(10, 42e0 ...) + f(11, 42e0...) + + _ = 42 .x // a blank must remain between 42 and .x + _ = 42. .x + _ = 42..x + _ = 42.0 .x + _ = 42.0.x + _ = .42 .x + _ = .42.x + _ = 42e0 .x + _ = 42e0.x + + // a blank must remain between the binary operator and the 2nd operand + _ = x/ *y + _ = x< -1 + _ = x< <-1 + _ = x+ +1 + _ = x- -1 + _ = x& &x + _ = x& ^x + + _ = f(x/ *y, x< -1, x< <-1, x+ +1, x- -1, x& &x, x& ^x) +} + + +func _() { + _ = T{} + _ = struct{}{} + _ = [10]T{} + _ = [...]T{} + _ = []T{} + _ = map[int]T{} +} + + +// one-line structs/interfaces in composite literals (up to a threshold) +func _() { + _ = struct{}{} + _ = struct{ x int }{0} + _ = struct{ x, y, z int }{0, 1, 2} + _ = struct{ int }{0} + _ = struct{ s struct { int } }{struct{ int}{0} } +} + + +func _() { + // do not modify literals + _ = "tab1 tab2 tab3 end" // string contains 3 tabs + _ = "tab1 tab2 tab3 end" // same string with 3 blanks - may be unaligned because editors see tabs in strings + _ = "" // this comment should be aligned with the one on the previous line + _ = `` + _ = ` +` +_ = `foo + bar` + _ = `three spaces before the end of the line starting here: +they must not be removed` +} + + +func _() { + // smart handling of indentation for multi-line raw strings + var _ = `` + var _ = `foo` + var _ = `foo +bar` + + +var _ = + `` +var _ = + `foo` +var _ = + // the next line should remain indented + `foo +bar` + + + var _ = // comment + `` + var _ = // comment + `foo` + var _ = // comment + // the next line should remain indented + `foo +bar` + + +var _ = /* comment */ `` +var _ = /* comment */ `foo` +var _ = /* comment */ `foo +bar` + + + var _ = /* comment */ + `` + var _ = /* comment */ + `foo` + var _ = /* comment */ + // the next line should remain indented + `foo +bar` + + +var board = []int( + `........... +........... +....●●●.... +....●●●.... +..●●●●●●●.. +..●●●○●●●.. +..●●●●●●●.. +....●●●.... +....●●●.... +........... +........... +`) + + + var state = S{ + "foo", + // the next line should remain indented + `........... +........... +....●●●.... +....●●●.... +..●●●●●●●.. +..●●●○●●●.. +..●●●●●●●.. +....●●●.... +....●●●.... +........... +........... +`, + "bar", + } +} + + +func _() { + // one-line function literals (body is on a single line) + _ = func() {} + _ = func() int { return 0 } + _ = func(x, y int) bool { m := (x+y)/2; return m < 0 } + + // multi-line function literals (body is not on one line) + _ = func() { + } + _ = func() int { + return 0 + } + _ = func(x, y int) bool { + m := (x+y)/2; return x < y } + + f(func() { + }) + f(func() int { + return 0 + }) + f(func(x, y int) bool { + m := (x+y)/2; return x < y }) +} + + +func _() { + _ = [][]int { + []int{1}, + []int{1, 2}, + []int{1, 2, 3}, + } + _ = [][]int { + {1}, + []int{1, 2}, + []int{1, 2, 3}, + } + _ = [][]int { + {1}, + {1, 2}, + {1, 2, 3}, + } + _ = [][]int {{1}, {1, 2}, {1, 2, 3}} +} + + +// various multi-line expressions +func _() { + // do not add extra indentation to multi-line string lists + _ = "foo" + "bar" + _ = "foo" + + "bar" + + "bah" + _ = []string { + "abc" + + "def", + "foo" + + "bar", + } +} + + +const _ = F1 + + `string = "%s";` + + `ptr = *;` + + `datafmt.T2 = s ["-" p "-"];` + + +const _ = + `datafmt "datafmt";` + + `default = "%v";` + + `array = *;` + + `datafmt.T3 = s {" " a a / ","};` + + +const _ = `datafmt "datafmt";` + +`default = "%v";` + +`array = *;` + +`datafmt.T3 = s {" " a a / ","};` + + +func _() { + _ = F1 + + `string = "%s";` + + `ptr = *;` + + `datafmt.T2 = s ["-" p "-"];` + + _ = + `datafmt "datafmt";` + + `default = "%v";` + + `array = *;` + + `datafmt.T3 = s {" " a a / ","};` + + _ = `datafmt "datafmt";` + + `default = "%v";` + + `array = *;` + + `datafmt.T3 = s {" " a a / ","};` +} + + +func _() { + // respect source lines in multi-line expressions + _ = a+ + b+ + c + _ = a < b || + b < a + _ = "933262154439441526816992388562667004907159682643816214685929" + + "638952175999932299156089414639761565182862536979208272237582" + + "51185210916864000000000000000000000000" // 100! + _ = "170141183460469231731687303715884105727" // prime +} + + +// Alignment after overlong lines +const ( + _ = "991" + _ = "2432902008176640000" // 20! + _ = "933262154439441526816992388562667004907159682643816214685929" + + "638952175999932299156089414639761565182862536979208272237582" + + "51185210916864000000000000000000000000" // 100! + _ = "170141183460469231731687303715884105727" // prime +) + + +// Correct placement of operators and comments in multi-line expressions +func _() { + _ = a + // comment + b + // comment + c + _ = "a" + + "b" + // comment + "c" + _ = "ba0408" + "7265717569726564" // field 71, encoding 2, string "required" +} + + +// Correct placement of terminating comma/closing parentheses in multi-line calls. +func _() { + f(1, + 2, + 3) + f(1, + 2, + 3, + ) + f(1, + 2, + 3) // comment + f(1, + 2, + 3, // comment + ) + f(1, + 2, + 3)// comment + f(1, + 2, + 3,// comment + ) +} + + +// Align comments in multi-line lists of single-line expressions. +var txpix = [NCOL]draw.Color{ + draw.Yellow, // yellow + draw.Cyan, // cyan + draw.Green, // lime green + draw.GreyBlue, // slate + draw.Red, /* red */ + draw.GreyGreen, /* olive green */ + draw.Blue, /* blue */ + draw.Color(0xFF55AAFF), /* pink */ + draw.Color(0xFFAAFFFF), /* lavender */ + draw.Color(0xBB005DFF), /* maroon */ +} + + +func same(t, u *Time) bool { + // respect source lines in multi-line expressions + return t.Year == u.Year && + t.Month == u.Month && + t.Day == u.Day && + t.Hour == u.Hour && + t.Minute == u.Minute && + t.Second == u.Second && + t.Weekday == u.Weekday && + t.ZoneOffset == u.ZoneOffset && + t.Zone == u.Zone +} + + +func (p *parser) charClass() { + // respect source lines in multi-line expressions + if cc.negate && len(cc.ranges) == 2 && + cc.ranges[0] == '\n' && cc.ranges[1] == '\n' { + nl := new(_NotNl) + p.re.add(nl) + } +} + + +func addState(s []state, inst instr, match []int) { + // handle comments correctly in multi-line expressions + for i := 0; i < l; i++ { + if s[i].inst.index() == index && // same instruction + s[i].match[0] < pos { // earlier match already going; leftmost wins + return s + } + } +} + +func (self *T) foo(x int) *T { return self } + +func _() { module.Func1().Func2() } + +func _() { + _ = new(T). + foo(1). + foo(2). + foo(3) + + _ = new(T). + foo(1). + foo(2). // inline comments + foo(3) + + _ = new(T).foo(1).foo(2).foo(3) + + // handle multiline argument list correctly + _ = new(T). + foo( + 1). + foo(2) + + _ = new(T).foo( + 1).foo(2) + + _ = Array[3 + +4] + + _ = Method(1, 2, + 3) + + _ = new(T). + foo(). + bar() . (*Type) + + _ = new(T). +foo(). +bar().(*Type). +baz() + + _ = new(T). + foo(). + bar()["idx"] + + _ = new(T). + foo(). + bar()["idx"] . + baz() + + _ = new(T). + foo(). + bar()[1:2] + + _ = new(T). + foo(). + bar()[1:2]. + baz() + + _ = new(T). + Field. + Array[3+ + 4]. + Table ["foo"]. + Blob. (*Type). + Slices[1:4]. + Method(1, 2, + 3). + Thingy + + _ = a.b.c + _ = a. + b. + c + _ = a.b().c + _ = a. + b(). + c + _ = a.b[0].c + _ = a. + b[0]. + c + _ = a.b[0:].c + _ = a. + b[0:]. + c + _ = a.b.(T).c + _ = a. + b. + (T). + c +} + + +// Don't introduce extra newlines in strangely formatted expression lists. +func f() { + // os.Open parameters should remain on two lines + if writer, err = os.Open(outfile, s.O_WRONLY|os.O_CREATE| + os.O_TRUNC, 0666); err != nil { + log.Fatal(err) + } +} diff --git a/src/pkg/go/printer/testdata/expressions.raw b/src/pkg/go/printer/testdata/expressions.raw new file mode 100644 index 000000000..d7819a3ba --- /dev/null +++ b/src/pkg/go/printer/testdata/expressions.raw @@ -0,0 +1,627 @@ +// Copyright 2009 The Go Authors. All rights reserved. +// Use of this source code is governed by a BSD-style +// license that can be found in the LICENSE file. + +package expressions + +type T struct { + x, y, z int +} + +var ( + a, b, c, d, e int + under_bar int + longIdentifier1, longIdentifier2, longIdentifier3 int + t0, t1, t2 T + s string + p *int +) + +func _() { + // no spaces around simple or parenthesized expressions + _ = (a + 0) + _ = a + b + _ = a + b + c + _ = a + b - c + _ = a - b - c + _ = a + (b * c) + _ = a + (b / c) + _ = a - (b % c) + _ = 1 + a + _ = a + 1 + _ = a + b + 1 + _ = s[a] + _ = s[a:] + _ = s[:b] + _ = s[1:2] + _ = s[a:b] + _ = s[0:len(s)] + _ = s[0] << 1 + _ = (s[0] << 1) & 0xf + _ = s[0]<<2 | s[1]>>4 + _ = "foo" + s + _ = s + "foo" + _ = 'a' + 'b' + _ = len(s) / 2 + _ = len(t0.x) / a + + // spaces around expressions of different precedence or expressions containing spaces + _ = a + -b + _ = a - ^b + _ = a / *p + _ = a + b*c + _ = 1 + b*c + _ = a + 2*c + _ = a + c*2 + _ = 1 + 2*3 + _ = s[1 : 2*3] + _ = s[a : b-c] + _ = s[0:] + _ = s[a+b] + _ = s[:b-c] + _ = s[a+b:] + _ = a[a<<b+1] + _ = a[a<<b+1:] + _ = s[a+b : len(s)] + _ = s[len(s):-a] + _ = s[a : len(s)+1] + _ = s[a:len(s)+1] + s + + // spaces around operators with equal or lower precedence than comparisons + _ = a == b + _ = a != b + _ = a > b + _ = a >= b + _ = a < b + _ = a <= b + _ = a < b && c > d + _ = a < b || c > d + + // spaces around "long" operands + _ = a + longIdentifier1 + _ = longIdentifier1 + a + _ = longIdentifier1 + longIdentifier2*longIdentifier3 + _ = s + "a longer string" + + // some selected cases + _ = a + t0.x + _ = a + t0.x + t1.x*t2.x + _ = a + b + c + d + e + 2*3 + _ = a + b + c + 2*3 + d + e + _ = (a + b + c) * 2 + _ = a - b + c - d + (a + b + c) + d&e + _ = under_bar - 1 + _ = Open(dpath+"/file", O_WRONLY|O_CREAT, 0666) + _ = int(c0&_Mask4)<<18 | int(c1&_Maskx)<<12 | int(c2&_Maskx)<<6 | int(c3&_Maskx) + + // the parser does not restrict expressions that may appear as statements + true + 42 + "foo" + x + (x) + a + b + a + b + c + a + (b * c) + a + (b / c) + 1 + a + a + 1 + s[a] + x << 1 + (s[0] << 1) & 0xf + "foo" + s + x == y + x < y || z > 42 +} + +func _() { + _ = a + b + _ = a + b + c + _ = a + b*c + _ = a + (b * c) + _ = (a + b) * c + _ = a + (b * c * d) + _ = a + (b*c + d) + + _ = 1 << x + _ = -1 << x + _ = 1<<x - 1 + _ = -1<<x - 1 + + _ = f(a + b) + _ = f(a + b + c) + _ = f(a + b*c) + _ = f(a + (b * c)) + _ = f(1<<x-1, 1<<x-2) + + _ = 1<<d.logWindowSize - 1 + + buf = make(x, 2*cap(b.buf)+n) + + dst[i*3+2] = dbuf[0] << 2 + dst[i*3+2] = dbuf[0]<<2 | dbuf[1]>>4 + + b.buf = b.buf[0 : b.off+m+n] + b.buf = b.buf[0 : b.off+m*n] + f(b.buf[0 : b.off+m+n]) + + signed += ' ' * 8 + tw.octal(header[148:155], chksum) + + _ = x > 0 && i >= 0 + + x1, x0 := x>>w2, x&m2 + z0 = t1<<w2 + t0 + z1 = (t1 + t0>>w2) >> w2 + q1, r1 := x1/d1, x1%d1 + r1 = r1*b2 | x0>>w2 + x1 = (x1 << z) | (x0 >> (uint(w) - z)) + x1 = x1<<z | x0>>(uint(w)-z) + + _ = buf[0 : len(buf)+1] + _ = buf[0 : n+1] + + a, b = b, a + a = b + c + a = b*c + d + _ = a*b + c + _ = a - b - c + _ = a - (b - c) + _ = a - b*c + _ = a - (b * c) + _ = a * b / c + _ = a / *b + _ = x[a|^b] + _ = x[a / *b] + _ = a & ^b + _ = a + +b + _ = a - -b + _ = x[a*-b] + _ = x[a + +b] + _ = x ^ y ^ z + _ = b[a>>24] ^ b[(a>>16)&0xFF] ^ b[(a>>8)&0xFF] ^ b[a&0xFF] + _ = len(longVariableName) * 2 + + _ = token(matchType + xlength<<lengthShift + xoffset) +} + +func f(x int, args ...int) { + f(0, args...) + f(1, args) + f(2, args[0]) + + // make sure syntactically legal code remains syntactically legal + f(3, 42 ...) // a blank must remain between 42 and ... + f(4, 42....) + f(5, 42....) + f(6, 42.0...) + f(7, 42.0...) + f(8, .42...) + f(9, .42...) + f(10, 42e0...) + f(11, 42e0...) + + _ = 42 .x // a blank must remain between 42 and .x + _ = 42..x + _ = 42..x + _ = 42.0.x + _ = 42.0.x + _ = .42.x + _ = .42.x + _ = 42e0.x + _ = 42e0.x + + // a blank must remain between the binary operator and the 2nd operand + _ = x / *y + _ = x < -1 + _ = x < <-1 + _ = x + +1 + _ = x - -1 + _ = x & &x + _ = x & ^x + + _ = f(x / *y, x < -1, x < <-1, x + +1, x - -1, x & &x, x & ^x) +} + +func _() { + _ = T{} + _ = struct{}{} + _ = [10]T{} + _ = [...]T{} + _ = []T{} + _ = map[int]T{} +} + +// one-line structs/interfaces in composite literals (up to a threshold) +func _() { + _ = struct{}{} + _ = struct{ x int }{0} + _ = struct{ x, y, z int }{0, 1, 2} + _ = struct{ int }{0} + _ = struct{ s struct{ int } }{struct{ int }{0}} +} + +func _() { + // do not modify literals + _ = "tab1 tab2 tab3 end" // string contains 3 tabs + _ = "tab1 tab2 tab3 end" // same string with 3 blanks - may be unaligned because editors see tabs in strings + _ = "" // this comment should be aligned with the one on the previous line + _ = `` + _ = ` +` + _ = `foo + bar` + _ = `three spaces before the end of the line starting here: +they must not be removed` +} + +func _() { + // smart handling of indentation for multi-line raw strings + var _ = `` + var _ = `foo` + var _ = `foo +bar` + + var _ = `` + var _ = `foo` + var _ = + // the next line should remain indented + `foo +bar` + + var _ = // comment + `` + var _ = // comment + `foo` + var _ = // comment + // the next line should remain indented + `foo +bar` + + var _ = /* comment */ `` + var _ = /* comment */ `foo` + var _ = /* comment */ `foo +bar` + + var _ = /* comment */ + `` + var _ = /* comment */ + `foo` + var _ = /* comment */ + // the next line should remain indented + `foo +bar` + + var board = []int( + `........... +........... +....●●●.... +....●●●.... +..●●●●●●●.. +..●●●○●●●.. +..●●●●●●●.. +....●●●.... +....●●●.... +........... +........... +`) + + var state = S{ + "foo", + // the next line should remain indented + `........... +........... +....●●●.... +....●●●.... +..●●●●●●●.. +..●●●○●●●.. +..●●●●●●●.. +....●●●.... +....●●●.... +........... +........... +`, + "bar", + } +} + +func _() { + // one-line function literals (body is on a single line) + _ = func() {} + _ = func() int { return 0 } + _ = func(x, y int) bool { m := (x + y) / 2; return m < 0 } + + // multi-line function literals (body is not on one line) + _ = func() { + } + _ = func() int { + return 0 + } + _ = func(x, y int) bool { + m := (x + y) / 2 + return x < y + } + + f(func() { + }) + f(func() int { + return 0 + }) + f(func(x, y int) bool { + m := (x + y) / 2 + return x < y + }) +} + +func _() { + _ = [][]int{ + []int{1}, + []int{1, 2}, + []int{1, 2, 3}, + } + _ = [][]int{ + {1}, + []int{1, 2}, + []int{1, 2, 3}, + } + _ = [][]int{ + {1}, + {1, 2}, + {1, 2, 3}, + } + _ = [][]int{{1}, {1, 2}, {1, 2, 3}} +} + +// various multi-line expressions +func _() { + // do not add extra indentation to multi-line string lists + _ = "foo" + "bar" + _ = "foo" + + "bar" + + "bah" + _ = []string{ + "abc" + + "def", + "foo" + + "bar", + } +} + +const _ = F1 + + `string = "%s";` + + `ptr = *;` + + `datafmt.T2 = s ["-" p "-"];` + +const _ = `datafmt "datafmt";` + + `default = "%v";` + + `array = *;` + + `datafmt.T3 = s {" " a a / ","};` + +const _ = `datafmt "datafmt";` + + `default = "%v";` + + `array = *;` + + `datafmt.T3 = s {" " a a / ","};` + +func _() { + _ = F1 + + `string = "%s";` + + `ptr = *;` + + `datafmt.T2 = s ["-" p "-"];` + + _ = + `datafmt "datafmt";` + + `default = "%v";` + + `array = *;` + + `datafmt.T3 = s {" " a a / ","};` + + _ = `datafmt "datafmt";` + + `default = "%v";` + + `array = *;` + + `datafmt.T3 = s {" " a a / ","};` +} + +func _() { + // respect source lines in multi-line expressions + _ = a + + b + + c + _ = a < b || + b < a + _ = "933262154439441526816992388562667004907159682643816214685929" + + "638952175999932299156089414639761565182862536979208272237582" + + "51185210916864000000000000000000000000" // 100! + _ = "170141183460469231731687303715884105727" // prime +} + +// Alignment after overlong lines +const ( + _ = "991" + _ = "2432902008176640000" // 20! + _ = "933262154439441526816992388562667004907159682643816214685929" + + "638952175999932299156089414639761565182862536979208272237582" + + "51185210916864000000000000000000000000" // 100! + _ = "170141183460469231731687303715884105727" // prime +) + +// Correct placement of operators and comments in multi-line expressions +func _() { + _ = a + // comment + b + // comment + c + _ = "a" + + "b" + // comment + "c" + _ = "ba0408" + "7265717569726564" // field 71, encoding 2, string "required" +} + +// Correct placement of terminating comma/closing parentheses in multi-line calls. +func _() { + f(1, + 2, + 3) + f(1, + 2, + 3, + ) + f(1, + 2, + 3) // comment + f(1, + 2, + 3, // comment + ) + f(1, + 2, + 3) // comment + f(1, + 2, + 3, // comment + ) +} + +// Align comments in multi-line lists of single-line expressions. +var txpix = [NCOL]draw.Color{ + draw.Yellow, // yellow + draw.Cyan, // cyan + draw.Green, // lime green + draw.GreyBlue, // slate + draw.Red, /* red */ + draw.GreyGreen, /* olive green */ + draw.Blue, /* blue */ + draw.Color(0xFF55AAFF), /* pink */ + draw.Color(0xFFAAFFFF), /* lavender */ + draw.Color(0xBB005DFF), /* maroon */ +} + +func same(t, u *Time) bool { + // respect source lines in multi-line expressions + return t.Year == u.Year && + t.Month == u.Month && + t.Day == u.Day && + t.Hour == u.Hour && + t.Minute == u.Minute && + t.Second == u.Second && + t.Weekday == u.Weekday && + t.ZoneOffset == u.ZoneOffset && + t.Zone == u.Zone +} + +func (p *parser) charClass() { + // respect source lines in multi-line expressions + if cc.negate && len(cc.ranges) == 2 && + cc.ranges[0] == '\n' && cc.ranges[1] == '\n' { + nl := new(_NotNl) + p.re.add(nl) + } +} + +func addState(s []state, inst instr, match []int) { + // handle comments correctly in multi-line expressions + for i := 0; i < l; i++ { + if s[i].inst.index() == index && // same instruction + s[i].match[0] < pos { // earlier match already going; leftmost wins + return s + } + } +} + +func (self *T) foo(x int) *T { return self } + +func _() { module.Func1().Func2() } + +func _() { + _ = new(T). + foo(1). + foo(2). + foo(3) + + _ = new(T). + foo(1). + foo(2). // inline comments + foo(3) + + _ = new(T).foo(1).foo(2).foo(3) + + // handle multiline argument list correctly + _ = new(T). + foo( + 1). + foo(2) + + _ = new(T).foo( + 1).foo(2) + + _ = Array[3+ + 4] + + _ = Method(1, 2, + 3) + + _ = new(T). + foo(). + bar().(*Type) + + _ = new(T). + foo(). + bar().(*Type). + baz() + + _ = new(T). + foo(). + bar()["idx"] + + _ = new(T). + foo(). + bar()["idx"]. + baz() + + _ = new(T). + foo(). + bar()[1:2] + + _ = new(T). + foo(). + bar()[1:2]. + baz() + + _ = new(T). + Field. + Array[3+ + 4]. + Table["foo"]. + Blob.(*Type). + Slices[1:4]. + Method(1, 2, + 3). + Thingy + + _ = a.b.c + _ = a. + b. + c + _ = a.b().c + _ = a. + b(). + c + _ = a.b[0].c + _ = a. + b[0]. + c + _ = a.b[0:].c + _ = a. + b[0:]. + c + _ = a.b.(T).c + _ = a. + b.(T). + c +} + +// Don't introduce extra newlines in strangely formatted expression lists. +func f() { + // os.Open parameters should remain on two lines + if writer, err = os.Open(outfile, s.O_WRONLY|os.O_CREATE| + os.O_TRUNC, 0666); err != nil { + log.Fatal(err) + } +} diff --git a/src/pkg/go/printer/testdata/linebreaks.golden b/src/pkg/go/printer/testdata/linebreaks.golden new file mode 100644 index 000000000..be780da67 --- /dev/null +++ b/src/pkg/go/printer/testdata/linebreaks.golden @@ -0,0 +1,223 @@ +// Copyright 2009 The Go Authors. All rights reserved. +// Use of this source code is governed by a BSD-style +// license that can be found in the LICENSE file. + +package linebreaks + +import ( + "bytes" + "fmt" + "io" + "os" + "reflect" + "strings" + "testing" +) + +type writerTestEntry struct { + header *Header + contents string +} + +type writerTest struct { + file string // filename of expected output + entries []*writerTestEntry +} + +var writerTests = []*writerTest{ + &writerTest{ + file: "testdata/writer.tar", + entries: []*writerTestEntry{ + &writerTestEntry{ + header: &Header{ + Name: "small.txt", + Mode: 0640, + Uid: 73025, + Gid: 5000, + Size: 5, + Mtime: 1246508266, + Typeflag: '0', + Uname: "dsymonds", + Gname: "eng", + }, + contents: "Kilts", + }, + &writerTestEntry{ + header: &Header{ + Name: "small2.txt", + Mode: 0640, + Uid: 73025, + Gid: 5000, + Size: 11, + Mtime: 1245217492, + Typeflag: '0', + Uname: "dsymonds", + Gname: "eng", + }, + contents: "Google.com\n", + }, + }, + }, + // The truncated test file was produced using these commands: + // dd if=/dev/zero bs=1048576 count=16384 > /tmp/16gig.txt + // tar -b 1 -c -f- /tmp/16gig.txt | dd bs=512 count=8 > writer-big.tar + &writerTest{ + file: "testdata/writer-big.tar", + entries: []*writerTestEntry{ + &writerTestEntry{ + header: &Header{ + Name: "tmp/16gig.txt", + Mode: 0640, + Uid: 73025, + Gid: 5000, + Size: 16 << 30, + Mtime: 1254699560, + Typeflag: '0', + Uname: "dsymonds", + Gname: "eng", + }, + // no contents + }, + }, + }, +} + +type untarTest struct { + file string + headers []*Header +} + +var untarTests = []*untarTest{ + &untarTest{ + file: "testdata/gnu.tar", + headers: []*Header{ + &Header{ + Name: "small.txt", + Mode: 0640, + Uid: 73025, + Gid: 5000, + Size: 5, + Mtime: 1244428340, + Typeflag: '0', + Uname: "dsymonds", + Gname: "eng", + }, + &Header{ + Name: "small2.txt", + Mode: 0640, + Uid: 73025, + Gid: 5000, + Size: 11, + Mtime: 1244436044, + Typeflag: '0', + Uname: "dsymonds", + Gname: "eng", + }, + }, + }, + &untarTest{ + file: "testdata/star.tar", + headers: []*Header{ + &Header{ + Name: "small.txt", + Mode: 0640, + Uid: 73025, + Gid: 5000, + Size: 5, + Mtime: 1244592783, + Typeflag: '0', + Uname: "dsymonds", + Gname: "eng", + Atime: 1244592783, + Ctime: 1244592783, + }, + &Header{ + Name: "small2.txt", + Mode: 0640, + Uid: 73025, + Gid: 5000, + Size: 11, + Mtime: 1244592783, + Typeflag: '0', + Uname: "dsymonds", + Gname: "eng", + Atime: 1244592783, + Ctime: 1244592783, + }, + }, + }, + &untarTest{ + file: "testdata/v7.tar", + headers: []*Header{ + &Header{ + Name: "small.txt", + Mode: 0444, + Uid: 73025, + Gid: 5000, + Size: 5, + Mtime: 1244593104, + Typeflag: '\x00', + }, + &Header{ + Name: "small2.txt", + Mode: 0444, + Uid: 73025, + Gid: 5000, + Size: 11, + Mtime: 1244593104, + Typeflag: '\x00', + }, + }, + }, +} + +var facts = map[int]string{ + 0: "1", + 1: "1", + 2: "2", + 10: "3628800", + 20: "2432902008176640000", + 100: "933262154439441526816992388562667004907159682643816214685929" + + "638952175999932299156089414639761565182862536979208272237582" + + "51185210916864000000000000000000000000", +} + +func usage() { + fmt.Fprintf(os.Stderr, + // TODO(gri): the 2nd string of this string list should not be indented + "usage: godoc package [name ...]\n"+ + " godoc -http=:6060\n") + flag.PrintDefaults() + os.Exit(2) +} + +func TestReader(t *testing.T) { +testLoop: + for i, test := range untarTests { + f, err := os.Open(test.file, os.O_RDONLY, 0444) + if err != nil { + t.Errorf("test %d: Unexpected error: %v", i, err) + continue + } + tr := NewReader(f) + for j, header := range test.headers { + hdr, err := tr.Next() + if err != nil || hdr == nil { + t.Errorf("test %d, entry %d: Didn't get entry: %v", i, j, err) + f.Close() + continue testLoop + } + if !reflect.DeepEqual(hdr, header) { + t.Errorf("test %d, entry %d: Incorrect header:\nhave %+v\nwant %+v", + i, j, *hdr, *header) + } + } + hdr, err := tr.Next() + if hdr != nil || err != nil { + t.Errorf("test %d: Unexpected entry or error: hdr=%v err=%v", i, err) + } + f.Close() + } +} + +// There should be exactly one linebreak after this comment. diff --git a/src/pkg/go/printer/testdata/linebreaks.input b/src/pkg/go/printer/testdata/linebreaks.input new file mode 100644 index 000000000..457b491e6 --- /dev/null +++ b/src/pkg/go/printer/testdata/linebreaks.input @@ -0,0 +1,223 @@ +// Copyright 2009 The Go Authors. All rights reserved. +// Use of this source code is governed by a BSD-style +// license that can be found in the LICENSE file. + +package linebreaks + +import ( + "bytes" + "fmt" + "io" + "os" + "reflect" + "strings" + "testing" +) + +type writerTestEntry struct { + header *Header + contents string +} + +type writerTest struct { + file string // filename of expected output + entries []*writerTestEntry +} + +var writerTests = []*writerTest{ + &writerTest{ + file: "testdata/writer.tar", + entries: []*writerTestEntry{ + &writerTestEntry{ + header: &Header{ + Name: "small.txt", + Mode: 0640, + Uid: 73025, + Gid: 5000, + Size: 5, + Mtime: 1246508266, + Typeflag: '0', + Uname: "dsymonds", + Gname: "eng", + }, + contents: "Kilts", + }, + &writerTestEntry{ + header: &Header{ + Name: "small2.txt", + Mode: 0640, + Uid: 73025, + Gid: 5000, + Size: 11, + Mtime: 1245217492, + Typeflag: '0', + Uname: "dsymonds", + Gname: "eng", + }, + contents: "Google.com\n", + }, + }, + }, + // The truncated test file was produced using these commands: + // dd if=/dev/zero bs=1048576 count=16384 > /tmp/16gig.txt + // tar -b 1 -c -f- /tmp/16gig.txt | dd bs=512 count=8 > writer-big.tar + &writerTest{ + file: "testdata/writer-big.tar", + entries: []*writerTestEntry{ + &writerTestEntry{ + header: &Header{ + Name: "tmp/16gig.txt", + Mode: 0640, + Uid: 73025, + Gid: 5000, + Size: 16 << 30, + Mtime: 1254699560, + Typeflag: '0', + Uname: "dsymonds", + Gname: "eng", + }, + // no contents + }, + }, + }, +} + +type untarTest struct { + file string + headers []*Header +} + +var untarTests = []*untarTest{ + &untarTest{ + file: "testdata/gnu.tar", + headers: []*Header{ + &Header{ + Name: "small.txt", + Mode: 0640, + Uid: 73025, + Gid: 5000, + Size: 5, + Mtime: 1244428340, + Typeflag: '0', + Uname: "dsymonds", + Gname: "eng", + }, + &Header{ + Name: "small2.txt", + Mode: 0640, + Uid: 73025, + Gid: 5000, + Size: 11, + Mtime: 1244436044, + Typeflag: '0', + Uname: "dsymonds", + Gname: "eng", + }, + }, + }, + &untarTest{ + file: "testdata/star.tar", + headers: []*Header{ + &Header{ + Name: "small.txt", + Mode: 0640, + Uid: 73025, + Gid: 5000, + Size: 5, + Mtime: 1244592783, + Typeflag: '0', + Uname: "dsymonds", + Gname: "eng", + Atime: 1244592783, + Ctime: 1244592783, + }, + &Header{ + Name: "small2.txt", + Mode: 0640, + Uid: 73025, + Gid: 5000, + Size: 11, + Mtime: 1244592783, + Typeflag: '0', + Uname: "dsymonds", + Gname: "eng", + Atime: 1244592783, + Ctime: 1244592783, + }, + }, + }, + &untarTest{ + file: "testdata/v7.tar", + headers: []*Header{ + &Header{ + Name: "small.txt", + Mode: 0444, + Uid: 73025, + Gid: 5000, + Size: 5, + Mtime: 1244593104, + Typeflag: '\x00', + }, + &Header{ + Name: "small2.txt", + Mode: 0444, + Uid: 73025, + Gid: 5000, + Size: 11, + Mtime: 1244593104, + Typeflag: '\x00', + }, + }, + }, +} + +var facts = map[int] string { + 0: "1", + 1: "1", + 2: "2", + 10: "3628800", + 20: "2432902008176640000", + 100: "933262154439441526816992388562667004907159682643816214685929" + + "638952175999932299156089414639761565182862536979208272237582" + + "51185210916864000000000000000000000000", +} + +func usage() { + fmt.Fprintf(os.Stderr, + // TODO(gri): the 2nd string of this string list should not be indented + "usage: godoc package [name ...]\n" + + " godoc -http=:6060\n") + flag.PrintDefaults() + os.Exit(2) +} + +func TestReader(t *testing.T) { +testLoop: + for i, test := range untarTests { + f, err := os.Open(test.file, os.O_RDONLY, 0444) + if err != nil { + t.Errorf("test %d: Unexpected error: %v", i, err) + continue + } + tr := NewReader(f) + for j, header := range test.headers { + hdr, err := tr.Next() + if err != nil || hdr == nil { + t.Errorf("test %d, entry %d: Didn't get entry: %v", i, j, err) + f.Close() + continue testLoop + } + if !reflect.DeepEqual(hdr, header) { + t.Errorf("test %d, entry %d: Incorrect header:\nhave %+v\nwant %+v", + i, j, *hdr, *header) + } + } + hdr, err := tr.Next() + if hdr != nil || err != nil { + t.Errorf("test %d: Unexpected entry or error: hdr=%v err=%v", i, err) + } + f.Close() + } +} + +// There should be exactly one linebreak after this comment. diff --git a/src/pkg/go/printer/testdata/parser.go b/src/pkg/go/printer/testdata/parser.go new file mode 100644 index 000000000..2d27af499 --- /dev/null +++ b/src/pkg/go/printer/testdata/parser.go @@ -0,0 +1,2153 @@ +// Copyright 2009 The Go Authors. All rights reserved. +// Use of this source code is governed by a BSD-style +// license that can be found in the LICENSE file. + +// Package parser implements a parser for Go source files. Input may be +// provided in a variety of forms (see the various Parse* functions); the +// output is an abstract syntax tree (AST) representing the Go source. The +// parser is invoked through one of the Parse* functions. +// +package parser + +import ( + "fmt" + "go/ast" + "go/scanner" + "go/token" +) + +// The mode parameter to the Parse* functions is a set of flags (or 0). +// They control the amount of source code parsed and other optional +// parser functionality. +// +const ( + PackageClauseOnly uint = 1 << iota // parsing stops after package clause + ImportsOnly // parsing stops after import declarations + ParseComments // parse comments and add them to AST + Trace // print a trace of parsed productions + DeclarationErrors // report declaration errors +) + +// The parser structure holds the parser's internal state. +type parser struct { + file *token.File + scanner.ErrorVector + scanner scanner.Scanner + + // Tracing/debugging + mode uint // parsing mode + trace bool // == (mode & Trace != 0) + indent uint // indentation used for tracing output + + // Comments + comments []*ast.CommentGroup + leadComment *ast.CommentGroup // last lead comment + lineComment *ast.CommentGroup // last line comment + + // Next token + pos token.Pos // token position + tok token.Token // one token look-ahead + lit string // token literal + + // Non-syntactic parser control + exprLev int // < 0: in control clause, >= 0: in expression + + // Ordinary identifer scopes + pkgScope *ast.Scope // pkgScope.Outer == nil + topScope *ast.Scope // top-most scope; may be pkgScope + unresolved []*ast.Ident // unresolved identifiers + imports []*ast.ImportSpec // list of imports + + // Label scope + // (maintained by open/close LabelScope) + labelScope *ast.Scope // label scope for current function + targetStack [][]*ast.Ident // stack of unresolved labels +} + +// scannerMode returns the scanner mode bits given the parser's mode bits. +func scannerMode(mode uint) uint { + var m uint = scanner.InsertSemis + if mode&ParseComments != 0 { + m |= scanner.ScanComments + } + return m +} + +func (p *parser) init(fset *token.FileSet, filename string, src []byte, mode uint) { + p.file = fset.AddFile(filename, fset.Base(), len(src)) + p.scanner.Init(p.file, src, p, scannerMode(mode)) + + p.mode = mode + p.trace = mode&Trace != 0 // for convenience (p.trace is used frequently) + + p.next() + + // set up the pkgScope here (as opposed to in parseFile) because + // there are other parser entry points (ParseExpr, etc.) + p.openScope() + p.pkgScope = p.topScope + + // for the same reason, set up a label scope + p.openLabelScope() +} + +// ---------------------------------------------------------------------------- +// Scoping support + +func (p *parser) openScope() { + p.topScope = ast.NewScope(p.topScope) +} + +func (p *parser) closeScope() { + p.topScope = p.topScope.Outer +} + +func (p *parser) openLabelScope() { + p.labelScope = ast.NewScope(p.labelScope) + p.targetStack = append(p.targetStack, nil) +} + +func (p *parser) closeLabelScope() { + // resolve labels + n := len(p.targetStack) - 1 + scope := p.labelScope + for _, ident := range p.targetStack[n] { + ident.Obj = scope.Lookup(ident.Name) + if ident.Obj == nil && p.mode&DeclarationErrors != 0 { + p.error(ident.Pos(), fmt.Sprintf("label %s undefined", ident.Name)) + } + } + // pop label scope + p.targetStack = p.targetStack[0:n] + p.labelScope = p.labelScope.Outer +} + +func (p *parser) declare(decl interface{}, scope *ast.Scope, kind ast.ObjKind, idents ...*ast.Ident) { + for _, ident := range idents { + assert(ident.Obj == nil, "identifier already declared or resolved") + if ident.Name != "_" { + obj := ast.NewObj(kind, ident.Name) + // remember the corresponding declaration for redeclaration + // errors and global variable resolution/typechecking phase + obj.Decl = decl + if alt := scope.Insert(obj); alt != nil && p.mode&DeclarationErrors != 0 { + prevDecl := "" + if pos := alt.Pos(); pos.IsValid() { + prevDecl = fmt.Sprintf("\n\tprevious declaration at %s", p.file.Position(pos)) + } + p.error(ident.Pos(), fmt.Sprintf("%s redeclared in this block%s", ident.Name, prevDecl)) + } + ident.Obj = obj + } + } +} + +func (p *parser) shortVarDecl(idents []*ast.Ident) { + // Go spec: A short variable declaration may redeclare variables + // provided they were originally declared in the same block with + // the same type, and at least one of the non-blank variables is new. + n := 0 // number of new variables + for _, ident := range idents { + assert(ident.Obj == nil, "identifier already declared or resolved") + if ident.Name != "_" { + obj := ast.NewObj(ast.Var, ident.Name) + // short var declarations cannot have redeclaration errors + // and are not global => no need to remember the respective + // declaration + alt := p.topScope.Insert(obj) + if alt == nil { + n++ // new declaration + alt = obj + } + ident.Obj = alt + } + } + if n == 0 && p.mode&DeclarationErrors != 0 { + p.error(idents[0].Pos(), "no new variables on left side of :=") + } +} + +// The unresolved object is a sentinel to mark identifiers that have been added +// to the list of unresolved identifiers. The sentinel is only used for verifying +// internal consistency. +var unresolved = new(ast.Object) + +func (p *parser) resolve(x ast.Expr) { + // nothing to do if x is not an identifier or the blank identifier + ident, _ := x.(*ast.Ident) + if ident == nil { + return + } + assert(ident.Obj == nil, "identifier already declared or resolved") + if ident.Name == "_" { + return + } + // try to resolve the identifier + for s := p.topScope; s != nil; s = s.Outer { + if obj := s.Lookup(ident.Name); obj != nil { + ident.Obj = obj + return + } + } + // all local scopes are known, so any unresolved identifier + // must be found either in the file scope, package scope + // (perhaps in another file), or universe scope --- collect + // them so that they can be resolved later + ident.Obj = unresolved + p.unresolved = append(p.unresolved, ident) +} + +// ---------------------------------------------------------------------------- +// Parsing support + +func (p *parser) printTrace(a ...interface{}) { + const dots = ". . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . " + + ". . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . " + const n = uint(len(dots)) + pos := p.file.Position(p.pos) + fmt.Printf("%5d:%3d: ", pos.Line, pos.Column) + i := 2 * p.indent + for ; i > n; i -= n { + fmt.Print(dots) + } + fmt.Print(dots[0:i]) + fmt.Println(a...) +} + +func trace(p *parser, msg string) *parser { + p.printTrace(msg, "(") + p.indent++ + return p +} + +// Usage pattern: defer un(trace(p, "...")); +func un(p *parser) { + p.indent-- + p.printTrace(")") +} + +// Advance to the next token. +func (p *parser) next0() { + // Because of one-token look-ahead, print the previous token + // when tracing as it provides a more readable output. The + // very first token (!p.pos.IsValid()) is not initialized + // (it is token.ILLEGAL), so don't print it . + if p.trace && p.pos.IsValid() { + s := p.tok.String() + switch { + case p.tok.IsLiteral(): + p.printTrace(s, p.lit) + case p.tok.IsOperator(), p.tok.IsKeyword(): + p.printTrace("\"" + s + "\"") + default: + p.printTrace(s) + } + } + + p.pos, p.tok, p.lit = p.scanner.Scan() +} + +// Consume a comment and return it and the line on which it ends. +func (p *parser) consumeComment() (comment *ast.Comment, endline int) { + // /*-style comments may end on a different line than where they start. + // Scan the comment for '\n' chars and adjust endline accordingly. + endline = p.file.Line(p.pos) + if p.lit[1] == '*' { + // don't use range here - no need to decode Unicode code points + for i := 0; i < len(p.lit); i++ { + if p.lit[i] == '\n' { + endline++ + } + } + } + + comment = &ast.Comment{p.pos, p.lit} + p.next0() + + return +} + +// Consume a group of adjacent comments, add it to the parser's +// comments list, and return it together with the line at which +// the last comment in the group ends. An empty line or non-comment +// token terminates a comment group. +// +func (p *parser) consumeCommentGroup() (comments *ast.CommentGroup, endline int) { + var list []*ast.Comment + endline = p.file.Line(p.pos) + for p.tok == token.COMMENT && endline+1 >= p.file.Line(p.pos) { + var comment *ast.Comment + comment, endline = p.consumeComment() + list = append(list, comment) + } + + // add comment group to the comments list + comments = &ast.CommentGroup{list} + p.comments = append(p.comments, comments) + + return +} + +// Advance to the next non-comment token. In the process, collect +// any comment groups encountered, and remember the last lead and +// and line comments. +// +// A lead comment is a comment group that starts and ends in a +// line without any other tokens and that is followed by a non-comment +// token on the line immediately after the comment group. +// +// A line comment is a comment group that follows a non-comment +// token on the same line, and that has no tokens after it on the line +// where it ends. +// +// Lead and line comments may be considered documentation that is +// stored in the AST. +// +func (p *parser) next() { + p.leadComment = nil + p.lineComment = nil + line := p.file.Line(p.pos) // current line + p.next0() + + if p.tok == token.COMMENT { + var comment *ast.CommentGroup + var endline int + + if p.file.Line(p.pos) == line { + // The comment is on same line as the previous token; it + // cannot be a lead comment but may be a line comment. + comment, endline = p.consumeCommentGroup() + if p.file.Line(p.pos) != endline { + // The next token is on a different line, thus + // the last comment group is a line comment. + p.lineComment = comment + } + } + + // consume successor comments, if any + endline = -1 + for p.tok == token.COMMENT { + comment, endline = p.consumeCommentGroup() + } + + if endline+1 == p.file.Line(p.pos) { + // The next token is following on the line immediately after the + // comment group, thus the last comment group is a lead comment. + p.leadComment = comment + } + } +} + +func (p *parser) error(pos token.Pos, msg string) { + p.Error(p.file.Position(pos), msg) +} + +func (p *parser) errorExpected(pos token.Pos, msg string) { + msg = "expected " + msg + if pos == p.pos { + // the error happened at the current position; + // make the error message more specific + if p.tok == token.SEMICOLON && p.lit[0] == '\n' { + msg += ", found newline" + } else { + msg += ", found '" + p.tok.String() + "'" + if p.tok.IsLiteral() { + msg += " " + p.lit + } + } + } + p.error(pos, msg) +} + +func (p *parser) expect(tok token.Token) token.Pos { + pos := p.pos + if p.tok != tok { + p.errorExpected(pos, "'"+tok.String()+"'") + } + p.next() // make progress + return pos +} + +func (p *parser) expectSemi() { + if p.tok != token.RPAREN && p.tok != token.RBRACE { + p.expect(token.SEMICOLON) + } +} + +func assert(cond bool, msg string) { + if !cond { + panic("go/parser internal error: " + msg) + } +} + +// ---------------------------------------------------------------------------- +// Identifiers + +func (p *parser) parseIdent() *ast.Ident { + pos := p.pos + name := "_" + if p.tok == token.IDENT { + name = p.lit + p.next() + } else { + p.expect(token.IDENT) // use expect() error handling + } + return &ast.Ident{pos, name, nil} +} + +func (p *parser) parseIdentList() (list []*ast.Ident) { + if p.trace { + defer un(trace(p, "IdentList")) + } + + list = append(list, p.parseIdent()) + for p.tok == token.COMMA { + p.next() + list = append(list, p.parseIdent()) + } + + return +} + +// ---------------------------------------------------------------------------- +// Common productions + +// If lhs is set, result list elements which are identifiers are not resolved. +func (p *parser) parseExprList(lhs bool) (list []ast.Expr) { + if p.trace { + defer un(trace(p, "ExpressionList")) + } + + list = append(list, p.parseExpr(lhs)) + for p.tok == token.COMMA { + p.next() + list = append(list, p.parseExpr(lhs)) + } + + return +} + +func (p *parser) parseLhsList() []ast.Expr { + list := p.parseExprList(true) + switch p.tok { + case token.DEFINE: + // lhs of a short variable declaration + p.shortVarDecl(p.makeIdentList(list)) + case token.COLON: + // lhs of a label declaration or a communication clause of a select + // statement (parseLhsList is not called when parsing the case clause + // of a switch statement): + // - labels are declared by the caller of parseLhsList + // - for communication clauses, if there is a stand-alone identifier + // followed by a colon, we have a syntax error; there is no need + // to resolve the identifier in that case + default: + // identifiers must be declared elsewhere + for _, x := range list { + p.resolve(x) + } + } + return list +} + +func (p *parser) parseRhsList() []ast.Expr { + return p.parseExprList(false) +} + +// ---------------------------------------------------------------------------- +// Types + +func (p *parser) parseType() ast.Expr { + if p.trace { + defer un(trace(p, "Type")) + } + + typ := p.tryType() + + if typ == nil { + pos := p.pos + p.errorExpected(pos, "type") + p.next() // make progress + return &ast.BadExpr{pos, p.pos} + } + + return typ +} + +// If the result is an identifier, it is not resolved. +func (p *parser) parseTypeName() ast.Expr { + if p.trace { + defer un(trace(p, "TypeName")) + } + + ident := p.parseIdent() + // don't resolve ident yet - it may be a parameter or field name + + if p.tok == token.PERIOD { + // ident is a package name + p.next() + p.resolve(ident) + sel := p.parseIdent() + return &ast.SelectorExpr{ident, sel} + } + + return ident +} + +func (p *parser) parseArrayType(ellipsisOk bool) ast.Expr { + if p.trace { + defer un(trace(p, "ArrayType")) + } + + lbrack := p.expect(token.LBRACK) + var len ast.Expr + if ellipsisOk && p.tok == token.ELLIPSIS { + len = &ast.Ellipsis{p.pos, nil} + p.next() + } else if p.tok != token.RBRACK { + len = p.parseRhs() + } + p.expect(token.RBRACK) + elt := p.parseType() + + return &ast.ArrayType{lbrack, len, elt} +} + +func (p *parser) makeIdentList(list []ast.Expr) []*ast.Ident { + idents := make([]*ast.Ident, len(list)) + for i, x := range list { + ident, isIdent := x.(*ast.Ident) + if !isIdent { + pos := x.(ast.Expr).Pos() + p.errorExpected(pos, "identifier") + ident = &ast.Ident{pos, "_", nil} + } + idents[i] = ident + } + return idents +} + +func (p *parser) parseFieldDecl(scope *ast.Scope) *ast.Field { + if p.trace { + defer un(trace(p, "FieldDecl")) + } + + doc := p.leadComment + + // fields + list, typ := p.parseVarList(false) + + // optional tag + var tag *ast.BasicLit + if p.tok == token.STRING { + tag = &ast.BasicLit{p.pos, p.tok, p.lit} + p.next() + } + + // analyze case + var idents []*ast.Ident + if typ != nil { + // IdentifierList Type + idents = p.makeIdentList(list) + } else { + // ["*"] TypeName (AnonymousField) + typ = list[0] // we always have at least one element + p.resolve(typ) + if n := len(list); n > 1 || !isTypeName(deref(typ)) { + pos := typ.Pos() + p.errorExpected(pos, "anonymous field") + typ = &ast.BadExpr{pos, list[n-1].End()} + } + } + + p.expectSemi() // call before accessing p.linecomment + + field := &ast.Field{doc, idents, typ, tag, p.lineComment} + p.declare(field, scope, ast.Var, idents...) + + return field +} + +func (p *parser) parseStructType() *ast.StructType { + if p.trace { + defer un(trace(p, "StructType")) + } + + pos := p.expect(token.STRUCT) + lbrace := p.expect(token.LBRACE) + scope := ast.NewScope(nil) // struct scope + var list []*ast.Field + for p.tok == token.IDENT || p.tok == token.MUL || p.tok == token.LPAREN { + // a field declaration cannot start with a '(' but we accept + // it here for more robust parsing and better error messages + // (parseFieldDecl will check and complain if necessary) + list = append(list, p.parseFieldDecl(scope)) + } + rbrace := p.expect(token.RBRACE) + + // TODO(gri): store struct scope in AST + return &ast.StructType{pos, &ast.FieldList{lbrace, list, rbrace}, false} +} + +func (p *parser) parsePointerType() *ast.StarExpr { + if p.trace { + defer un(trace(p, "PointerType")) + } + + star := p.expect(token.MUL) + base := p.parseType() + + return &ast.StarExpr{star, base} +} + +func (p *parser) tryVarType(isParam bool) ast.Expr { + if isParam && p.tok == token.ELLIPSIS { + pos := p.pos + p.next() + typ := p.tryIdentOrType(isParam) // don't use parseType so we can provide better error message + if typ == nil { + p.error(pos, "'...' parameter is missing type") + typ = &ast.BadExpr{pos, p.pos} + } + if p.tok != token.RPAREN { + p.error(pos, "can use '...' with last parameter type only") + } + return &ast.Ellipsis{pos, typ} + } + return p.tryIdentOrType(false) +} + +func (p *parser) parseVarType(isParam bool) ast.Expr { + typ := p.tryVarType(isParam) + if typ == nil { + pos := p.pos + p.errorExpected(pos, "type") + p.next() // make progress + typ = &ast.BadExpr{pos, p.pos} + } + return typ +} + +func (p *parser) parseVarList(isParam bool) (list []ast.Expr, typ ast.Expr) { + if p.trace { + defer un(trace(p, "VarList")) + } + + // a list of identifiers looks like a list of type names + for { + // parseVarType accepts any type (including parenthesized ones) + // even though the syntax does not permit them here: we + // accept them all for more robust parsing and complain + // afterwards + list = append(list, p.parseVarType(isParam)) + if p.tok != token.COMMA { + break + } + p.next() + } + + // if we had a list of identifiers, it must be followed by a type + typ = p.tryVarType(isParam) + if typ != nil { + p.resolve(typ) + } + + return +} + +func (p *parser) parseParameterList(scope *ast.Scope, ellipsisOk bool) (params []*ast.Field) { + if p.trace { + defer un(trace(p, "ParameterList")) + } + + list, typ := p.parseVarList(ellipsisOk) + if typ != nil { + // IdentifierList Type + idents := p.makeIdentList(list) + field := &ast.Field{nil, idents, typ, nil, nil} + params = append(params, field) + // Go spec: The scope of an identifier denoting a function + // parameter or result variable is the function body. + p.declare(field, scope, ast.Var, idents...) + if p.tok == token.COMMA { + p.next() + } + + for p.tok != token.RPAREN && p.tok != token.EOF { + idents := p.parseIdentList() + typ := p.parseVarType(ellipsisOk) + field := &ast.Field{nil, idents, typ, nil, nil} + params = append(params, field) + // Go spec: The scope of an identifier denoting a function + // parameter or result variable is the function body. + p.declare(field, scope, ast.Var, idents...) + if p.tok != token.COMMA { + break + } + p.next() + } + + } else { + // Type { "," Type } (anonymous parameters) + params = make([]*ast.Field, len(list)) + for i, x := range list { + p.resolve(x) + params[i] = &ast.Field{Type: x} + } + } + + return +} + +func (p *parser) parseParameters(scope *ast.Scope, ellipsisOk bool) *ast.FieldList { + if p.trace { + defer un(trace(p, "Parameters")) + } + + var params []*ast.Field + lparen := p.expect(token.LPAREN) + if p.tok != token.RPAREN { + params = p.parseParameterList(scope, ellipsisOk) + } + rparen := p.expect(token.RPAREN) + + return &ast.FieldList{lparen, params, rparen} +} + +func (p *parser) parseResult(scope *ast.Scope) *ast.FieldList { + if p.trace { + defer un(trace(p, "Result")) + } + + if p.tok == token.LPAREN { + return p.parseParameters(scope, false) + } + + typ := p.tryType() + if typ != nil { + list := make([]*ast.Field, 1) + list[0] = &ast.Field{Type: typ} + return &ast.FieldList{List: list} + } + + return nil +} + +func (p *parser) parseSignature(scope *ast.Scope) (params, results *ast.FieldList) { + if p.trace { + defer un(trace(p, "Signature")) + } + + params = p.parseParameters(scope, true) + results = p.parseResult(scope) + + return +} + +func (p *parser) parseFuncType() (*ast.FuncType, *ast.Scope) { + if p.trace { + defer un(trace(p, "FuncType")) + } + + pos := p.expect(token.FUNC) + scope := ast.NewScope(p.topScope) // function scope + params, results := p.parseSignature(scope) + + return &ast.FuncType{pos, params, results}, scope +} + +func (p *parser) parseMethodSpec(scope *ast.Scope) *ast.Field { + if p.trace { + defer un(trace(p, "MethodSpec")) + } + + doc := p.leadComment + var idents []*ast.Ident + var typ ast.Expr + x := p.parseTypeName() + if ident, isIdent := x.(*ast.Ident); isIdent && p.tok == token.LPAREN { + // method + idents = []*ast.Ident{ident} + scope := ast.NewScope(nil) // method scope + params, results := p.parseSignature(scope) + typ = &ast.FuncType{token.NoPos, params, results} + } else { + // embedded interface + typ = x + } + p.expectSemi() // call before accessing p.linecomment + + spec := &ast.Field{doc, idents, typ, nil, p.lineComment} + p.declare(spec, scope, ast.Fun, idents...) + + return spec +} + +func (p *parser) parseInterfaceType() *ast.InterfaceType { + if p.trace { + defer un(trace(p, "InterfaceType")) + } + + pos := p.expect(token.INTERFACE) + lbrace := p.expect(token.LBRACE) + scope := ast.NewScope(nil) // interface scope + var list []*ast.Field + for p.tok == token.IDENT { + list = append(list, p.parseMethodSpec(scope)) + } + rbrace := p.expect(token.RBRACE) + + // TODO(gri): store interface scope in AST + return &ast.InterfaceType{pos, &ast.FieldList{lbrace, list, rbrace}, false} +} + +func (p *parser) parseMapType() *ast.MapType { + if p.trace { + defer un(trace(p, "MapType")) + } + + pos := p.expect(token.MAP) + p.expect(token.LBRACK) + key := p.parseType() + p.expect(token.RBRACK) + value := p.parseType() + + return &ast.MapType{pos, key, value} +} + +func (p *parser) parseChanType() *ast.ChanType { + if p.trace { + defer un(trace(p, "ChanType")) + } + + pos := p.pos + dir := ast.SEND | ast.RECV + if p.tok == token.CHAN { + p.next() + if p.tok == token.ARROW { + p.next() + dir = ast.SEND + } + } else { + p.expect(token.ARROW) + p.expect(token.CHAN) + dir = ast.RECV + } + value := p.parseType() + + return &ast.ChanType{pos, dir, value} +} + +// If the result is an identifier, it is not resolved. +func (p *parser) tryIdentOrType(ellipsisOk bool) ast.Expr { + switch p.tok { + case token.IDENT: + return p.parseTypeName() + case token.LBRACK: + return p.parseArrayType(ellipsisOk) + case token.STRUCT: + return p.parseStructType() + case token.MUL: + return p.parsePointerType() + case token.FUNC: + typ, _ := p.parseFuncType() + return typ + case token.INTERFACE: + return p.parseInterfaceType() + case token.MAP: + return p.parseMapType() + case token.CHAN, token.ARROW: + return p.parseChanType() + case token.LPAREN: + lparen := p.pos + p.next() + typ := p.parseType() + rparen := p.expect(token.RPAREN) + return &ast.ParenExpr{lparen, typ, rparen} + } + + // no type found + return nil +} + +func (p *parser) tryType() ast.Expr { + typ := p.tryIdentOrType(false) + if typ != nil { + p.resolve(typ) + } + return typ +} + +// ---------------------------------------------------------------------------- +// Blocks + +func (p *parser) parseStmtList() (list []ast.Stmt) { + if p.trace { + defer un(trace(p, "StatementList")) + } + + for p.tok != token.CASE && p.tok != token.DEFAULT && p.tok != token.RBRACE && p.tok != token.EOF { + list = append(list, p.parseStmt()) + } + + return +} + +func (p *parser) parseBody(scope *ast.Scope) *ast.BlockStmt { + if p.trace { + defer un(trace(p, "Body")) + } + + lbrace := p.expect(token.LBRACE) + p.topScope = scope // open function scope + p.openLabelScope() + list := p.parseStmtList() + p.closeLabelScope() + p.closeScope() + rbrace := p.expect(token.RBRACE) + + return &ast.BlockStmt{lbrace, list, rbrace} +} + +func (p *parser) parseBlockStmt() *ast.BlockStmt { + if p.trace { + defer un(trace(p, "BlockStmt")) + } + + lbrace := p.expect(token.LBRACE) + p.openScope() + list := p.parseStmtList() + p.closeScope() + rbrace := p.expect(token.RBRACE) + + return &ast.BlockStmt{lbrace, list, rbrace} +} + +// ---------------------------------------------------------------------------- +// Expressions + +func (p *parser) parseFuncTypeOrLit() ast.Expr { + if p.trace { + defer un(trace(p, "FuncTypeOrLit")) + } + + typ, scope := p.parseFuncType() + if p.tok != token.LBRACE { + // function type only + return typ + } + + p.exprLev++ + body := p.parseBody(scope) + p.exprLev-- + + return &ast.FuncLit{typ, body} +} + +// parseOperand may return an expression or a raw type (incl. array +// types of the form [...]T. Callers must verify the result. +// If lhs is set and the result is an identifier, it is not resolved. +// +func (p *parser) parseOperand(lhs bool) ast.Expr { + if p.trace { + defer un(trace(p, "Operand")) + } + + switch p.tok { + case token.IDENT: + x := p.parseIdent() + if !lhs { + p.resolve(x) + } + return x + + case token.INT, token.FLOAT, token.IMAG, token.CHAR, token.STRING: + x := &ast.BasicLit{p.pos, p.tok, p.lit} + p.next() + return x + + case token.LPAREN: + lparen := p.pos + p.next() + p.exprLev++ + x := p.parseRhs() + p.exprLev-- + rparen := p.expect(token.RPAREN) + return &ast.ParenExpr{lparen, x, rparen} + + case token.FUNC: + return p.parseFuncTypeOrLit() + + default: + if typ := p.tryIdentOrType(true); typ != nil { + // could be type for composite literal or conversion + _, isIdent := typ.(*ast.Ident) + assert(!isIdent, "type cannot be identifier") + return typ + } + } + + pos := p.pos + p.errorExpected(pos, "operand") + p.next() // make progress + return &ast.BadExpr{pos, p.pos} +} + +func (p *parser) parseSelector(x ast.Expr) ast.Expr { + if p.trace { + defer un(trace(p, "Selector")) + } + + sel := p.parseIdent() + + return &ast.SelectorExpr{x, sel} +} + +func (p *parser) parseTypeAssertion(x ast.Expr) ast.Expr { + if p.trace { + defer un(trace(p, "TypeAssertion")) + } + + p.expect(token.LPAREN) + var typ ast.Expr + if p.tok == token.TYPE { + // type switch: typ == nil + p.next() + } else { + typ = p.parseType() + } + p.expect(token.RPAREN) + + return &ast.TypeAssertExpr{x, typ} +} + +func (p *parser) parseIndexOrSlice(x ast.Expr) ast.Expr { + if p.trace { + defer un(trace(p, "IndexOrSlice")) + } + + lbrack := p.expect(token.LBRACK) + p.exprLev++ + var low, high ast.Expr + isSlice := false + if p.tok != token.COLON { + low = p.parseRhs() + } + if p.tok == token.COLON { + isSlice = true + p.next() + if p.tok != token.RBRACK { + high = p.parseRhs() + } + } + p.exprLev-- + rbrack := p.expect(token.RBRACK) + + if isSlice { + return &ast.SliceExpr{x, lbrack, low, high, rbrack} + } + return &ast.IndexExpr{x, lbrack, low, rbrack} +} + +func (p *parser) parseCallOrConversion(fun ast.Expr) *ast.CallExpr { + if p.trace { + defer un(trace(p, "CallOrConversion")) + } + + lparen := p.expect(token.LPAREN) + p.exprLev++ + var list []ast.Expr + var ellipsis token.Pos + for p.tok != token.RPAREN && p.tok != token.EOF && !ellipsis.IsValid() { + list = append(list, p.parseRhs()) + if p.tok == token.ELLIPSIS { + ellipsis = p.pos + p.next() + } + if p.tok != token.COMMA { + break + } + p.next() + } + p.exprLev-- + rparen := p.expect(token.RPAREN) + + return &ast.CallExpr{fun, lparen, list, ellipsis, rparen} +} + +func (p *parser) parseElement(keyOk bool) ast.Expr { + if p.trace { + defer un(trace(p, "Element")) + } + + if p.tok == token.LBRACE { + return p.parseLiteralValue(nil) + } + + x := p.parseExpr(keyOk) // don't resolve if map key + if keyOk { + if p.tok == token.COLON { + colon := p.pos + p.next() + return &ast.KeyValueExpr{x, colon, p.parseElement(false)} + } + p.resolve(x) // not a map key + } + + return x +} + +func (p *parser) parseElementList() (list []ast.Expr) { + if p.trace { + defer un(trace(p, "ElementList")) + } + + for p.tok != token.RBRACE && p.tok != token.EOF { + list = append(list, p.parseElement(true)) + if p.tok != token.COMMA { + break + } + p.next() + } + + return +} + +func (p *parser) parseLiteralValue(typ ast.Expr) ast.Expr { + if p.trace { + defer un(trace(p, "LiteralValue")) + } + + lbrace := p.expect(token.LBRACE) + var elts []ast.Expr + p.exprLev++ + if p.tok != token.RBRACE { + elts = p.parseElementList() + } + p.exprLev-- + rbrace := p.expect(token.RBRACE) + return &ast.CompositeLit{typ, lbrace, elts, rbrace} +} + +// checkExpr checks that x is an expression (and not a type). +func (p *parser) checkExpr(x ast.Expr) ast.Expr { + switch t := unparen(x).(type) { + case *ast.BadExpr: + case *ast.Ident: + case *ast.BasicLit: + case *ast.FuncLit: + case *ast.CompositeLit: + case *ast.ParenExpr: + panic("unreachable") + case *ast.SelectorExpr: + case *ast.IndexExpr: + case *ast.SliceExpr: + case *ast.TypeAssertExpr: + if t.Type == nil { + // the form X.(type) is only allowed in type switch expressions + p.errorExpected(x.Pos(), "expression") + x = &ast.BadExpr{x.Pos(), x.End()} + } + case *ast.CallExpr: + case *ast.StarExpr: + case *ast.UnaryExpr: + if t.Op == token.RANGE { + // the range operator is only allowed at the top of a for statement + p.errorExpected(x.Pos(), "expression") + x = &ast.BadExpr{x.Pos(), x.End()} + } + case *ast.BinaryExpr: + default: + // all other nodes are not proper expressions + p.errorExpected(x.Pos(), "expression") + x = &ast.BadExpr{x.Pos(), x.End()} + } + return x +} + +// isTypeName returns true iff x is a (qualified) TypeName. +func isTypeName(x ast.Expr) bool { + switch t := x.(type) { + case *ast.BadExpr: + case *ast.Ident: + case *ast.SelectorExpr: + _, isIdent := t.X.(*ast.Ident) + return isIdent + default: + return false // all other nodes are not type names + } + return true +} + +// isLiteralType returns true iff x is a legal composite literal type. +func isLiteralType(x ast.Expr) bool { + switch t := x.(type) { + case *ast.BadExpr: + case *ast.Ident: + case *ast.SelectorExpr: + _, isIdent := t.X.(*ast.Ident) + return isIdent + case *ast.ArrayType: + case *ast.StructType: + case *ast.MapType: + default: + return false // all other nodes are not legal composite literal types + } + return true +} + +// If x is of the form *T, deref returns T, otherwise it returns x. +func deref(x ast.Expr) ast.Expr { + if p, isPtr := x.(*ast.StarExpr); isPtr { + x = p.X + } + return x +} + +// If x is of the form (T), unparen returns unparen(T), otherwise it returns x. +func unparen(x ast.Expr) ast.Expr { + if p, isParen := x.(*ast.ParenExpr); isParen { + x = unparen(p.X) + } + return x +} + +// checkExprOrType checks that x is an expression or a type +// (and not a raw type such as [...]T). +// +func (p *parser) checkExprOrType(x ast.Expr) ast.Expr { + switch t := unparen(x).(type) { + case *ast.ParenExpr: + panic("unreachable") + case *ast.UnaryExpr: + if t.Op == token.RANGE { + // the range operator is only allowed at the top of a for statement + p.errorExpected(x.Pos(), "expression") + x = &ast.BadExpr{x.Pos(), x.End()} + } + case *ast.ArrayType: + if len, isEllipsis := t.Len.(*ast.Ellipsis); isEllipsis { + p.error(len.Pos(), "expected array length, found '...'") + x = &ast.BadExpr{x.Pos(), x.End()} + } + } + + // all other nodes are expressions or types + return x +} + +// If lhs is set and the result is an identifier, it is not resolved. +func (p *parser) parsePrimaryExpr(lhs bool) ast.Expr { + if p.trace { + defer un(trace(p, "PrimaryExpr")) + } + + x := p.parseOperand(lhs) +L: + for { + switch p.tok { + case token.PERIOD: + p.next() + if lhs { + p.resolve(x) + } + switch p.tok { + case token.IDENT: + x = p.parseSelector(p.checkExpr(x)) + case token.LPAREN: + x = p.parseTypeAssertion(p.checkExpr(x)) + default: + pos := p.pos + p.next() // make progress + p.errorExpected(pos, "selector or type assertion") + x = &ast.BadExpr{pos, p.pos} + } + case token.LBRACK: + if lhs { + p.resolve(x) + } + x = p.parseIndexOrSlice(p.checkExpr(x)) + case token.LPAREN: + if lhs { + p.resolve(x) + } + x = p.parseCallOrConversion(p.checkExprOrType(x)) + case token.LBRACE: + if isLiteralType(x) && (p.exprLev >= 0 || !isTypeName(x)) { + if lhs { + p.resolve(x) + } + x = p.parseLiteralValue(x) + } else { + break L + } + default: + break L + } + lhs = false // no need to try to resolve again + } + + return x +} + +// If lhs is set and the result is an identifier, it is not resolved. +func (p *parser) parseUnaryExpr(lhs bool) ast.Expr { + if p.trace { + defer un(trace(p, "UnaryExpr")) + } + + switch p.tok { + case token.ADD, token.SUB, token.NOT, token.XOR, token.AND, token.RANGE: + pos, op := p.pos, p.tok + p.next() + x := p.parseUnaryExpr(false) + return &ast.UnaryExpr{pos, op, p.checkExpr(x)} + + case token.ARROW: + // channel type or receive expression + pos := p.pos + p.next() + if p.tok == token.CHAN { + p.next() + value := p.parseType() + return &ast.ChanType{pos, ast.RECV, value} + } + + x := p.parseUnaryExpr(false) + return &ast.UnaryExpr{pos, token.ARROW, p.checkExpr(x)} + + case token.MUL: + // pointer type or unary "*" expression + pos := p.pos + p.next() + x := p.parseUnaryExpr(false) + return &ast.StarExpr{pos, p.checkExprOrType(x)} + } + + return p.parsePrimaryExpr(lhs) +} + +// If lhs is set and the result is an identifier, it is not resolved. +func (p *parser) parseBinaryExpr(lhs bool, prec1 int) ast.Expr { + if p.trace { + defer un(trace(p, "BinaryExpr")) + } + + x := p.parseUnaryExpr(lhs) + for prec := p.tok.Precedence(); prec >= prec1; prec-- { + for p.tok.Precedence() == prec { + pos, op := p.pos, p.tok + p.next() + if lhs { + p.resolve(x) + lhs = false + } + y := p.parseBinaryExpr(false, prec+1) + x = &ast.BinaryExpr{p.checkExpr(x), pos, op, p.checkExpr(y)} + } + } + + return x +} + +// If lhs is set and the result is an identifier, it is not resolved. +// TODO(gri): parseExpr may return a type or even a raw type ([..]int) - +// should reject when a type/raw type is obviously not allowed +func (p *parser) parseExpr(lhs bool) ast.Expr { + if p.trace { + defer un(trace(p, "Expression")) + } + + return p.parseBinaryExpr(lhs, token.LowestPrec+1) +} + +func (p *parser) parseRhs() ast.Expr { + return p.parseExpr(false) +} + +// ---------------------------------------------------------------------------- +// Statements + +func (p *parser) parseSimpleStmt(labelOk bool) ast.Stmt { + if p.trace { + defer un(trace(p, "SimpleStmt")) + } + + x := p.parseLhsList() + + switch p.tok { + case + token.DEFINE, token.ASSIGN, token.ADD_ASSIGN, + token.SUB_ASSIGN, token.MUL_ASSIGN, token.QUO_ASSIGN, + token.REM_ASSIGN, token.AND_ASSIGN, token.OR_ASSIGN, + token.XOR_ASSIGN, token.SHL_ASSIGN, token.SHR_ASSIGN, token.AND_NOT_ASSIGN: + // assignment statement + pos, tok := p.pos, p.tok + p.next() + y := p.parseRhsList() + return &ast.AssignStmt{x, pos, tok, y} + } + + if len(x) > 1 { + p.errorExpected(x[0].Pos(), "1 expression") + // continue with first expression + } + + switch p.tok { + case token.COLON: + // labeled statement + colon := p.pos + p.next() + if label, isIdent := x[0].(*ast.Ident); labelOk && isIdent { + // Go spec: The scope of a label is the body of the function + // in which it is declared and excludes the body of any nested + // function. + stmt := &ast.LabeledStmt{label, colon, p.parseStmt()} + p.declare(stmt, p.labelScope, ast.Lbl, label) + return stmt + } + p.error(x[0].Pos(), "illegal label declaration") + return &ast.BadStmt{x[0].Pos(), colon + 1} + + case token.ARROW: + // send statement + arrow := p.pos + p.next() // consume "<-" + y := p.parseRhs() + return &ast.SendStmt{x[0], arrow, y} + + case token.INC, token.DEC: + // increment or decrement + s := &ast.IncDecStmt{x[0], p.pos, p.tok} + p.next() // consume "++" or "--" + return s + } + + // expression + return &ast.ExprStmt{x[0]} +} + +func (p *parser) parseCallExpr() *ast.CallExpr { + x := p.parseRhs() + if call, isCall := x.(*ast.CallExpr); isCall { + return call + } + p.errorExpected(x.Pos(), "function/method call") + return nil +} + +func (p *parser) parseGoStmt() ast.Stmt { + if p.trace { + defer un(trace(p, "GoStmt")) + } + + pos := p.expect(token.GO) + call := p.parseCallExpr() + p.expectSemi() + if call == nil { + return &ast.BadStmt{pos, pos + 2} // len("go") + } + + return &ast.GoStmt{pos, call} +} + +func (p *parser) parseDeferStmt() ast.Stmt { + if p.trace { + defer un(trace(p, "DeferStmt")) + } + + pos := p.expect(token.DEFER) + call := p.parseCallExpr() + p.expectSemi() + if call == nil { + return &ast.BadStmt{pos, pos + 5} // len("defer") + } + + return &ast.DeferStmt{pos, call} +} + +func (p *parser) parseReturnStmt() *ast.ReturnStmt { + if p.trace { + defer un(trace(p, "ReturnStmt")) + } + + pos := p.pos + p.expect(token.RETURN) + var x []ast.Expr + if p.tok != token.SEMICOLON && p.tok != token.RBRACE { + x = p.parseRhsList() + } + p.expectSemi() + + return &ast.ReturnStmt{pos, x} +} + +func (p *parser) parseBranchStmt(tok token.Token) *ast.BranchStmt { + if p.trace { + defer un(trace(p, "BranchStmt")) + } + + pos := p.expect(tok) + var label *ast.Ident + if tok != token.FALLTHROUGH && p.tok == token.IDENT { + label = p.parseIdent() + // add to list of unresolved targets + n := len(p.targetStack) - 1 + p.targetStack[n] = append(p.targetStack[n], label) + } + p.expectSemi() + + return &ast.BranchStmt{pos, tok, label} +} + +func (p *parser) makeExpr(s ast.Stmt) ast.Expr { + if s == nil { + return nil + } + if es, isExpr := s.(*ast.ExprStmt); isExpr { + return p.checkExpr(es.X) + } + p.error(s.Pos(), "expected condition, found simple statement") + return &ast.BadExpr{s.Pos(), s.End()} +} + +func (p *parser) parseIfStmt() *ast.IfStmt { + if p.trace { + defer un(trace(p, "IfStmt")) + } + + pos := p.expect(token.IF) + p.openScope() + defer p.closeScope() + + var s ast.Stmt + var x ast.Expr + { + prevLev := p.exprLev + p.exprLev = -1 + if p.tok == token.SEMICOLON { + p.next() + x = p.parseRhs() + } else { + s = p.parseSimpleStmt(false) + if p.tok == token.SEMICOLON { + p.next() + x = p.parseRhs() + } else { + x = p.makeExpr(s) + s = nil + } + } + p.exprLev = prevLev + } + + body := p.parseBlockStmt() + var else_ ast.Stmt + if p.tok == token.ELSE { + p.next() + else_ = p.parseStmt() + } else { + p.expectSemi() + } + + return &ast.IfStmt{pos, s, x, body, else_} +} + +func (p *parser) parseTypeList() (list []ast.Expr) { + if p.trace { + defer un(trace(p, "TypeList")) + } + + list = append(list, p.parseType()) + for p.tok == token.COMMA { + p.next() + list = append(list, p.parseType()) + } + + return +} + +func (p *parser) parseCaseClause(exprSwitch bool) *ast.CaseClause { + if p.trace { + defer un(trace(p, "CaseClause")) + } + + pos := p.pos + var list []ast.Expr + if p.tok == token.CASE { + p.next() + if exprSwitch { + list = p.parseRhsList() + } else { + list = p.parseTypeList() + } + } else { + p.expect(token.DEFAULT) + } + + colon := p.expect(token.COLON) + p.openScope() + body := p.parseStmtList() + p.closeScope() + + return &ast.CaseClause{pos, list, colon, body} +} + +func isExprSwitch(s ast.Stmt) bool { + if s == nil { + return true + } + if e, ok := s.(*ast.ExprStmt); ok { + if a, ok := e.X.(*ast.TypeAssertExpr); ok { + return a.Type != nil // regular type assertion + } + return true + } + return false +} + +func (p *parser) parseSwitchStmt() ast.Stmt { + if p.trace { + defer un(trace(p, "SwitchStmt")) + } + + pos := p.expect(token.SWITCH) + p.openScope() + defer p.closeScope() + + var s1, s2 ast.Stmt + if p.tok != token.LBRACE { + prevLev := p.exprLev + p.exprLev = -1 + if p.tok != token.SEMICOLON { + s2 = p.parseSimpleStmt(false) + } + if p.tok == token.SEMICOLON { + p.next() + s1 = s2 + s2 = nil + if p.tok != token.LBRACE { + s2 = p.parseSimpleStmt(false) + } + } + p.exprLev = prevLev + } + + exprSwitch := isExprSwitch(s2) + lbrace := p.expect(token.LBRACE) + var list []ast.Stmt + for p.tok == token.CASE || p.tok == token.DEFAULT { + list = append(list, p.parseCaseClause(exprSwitch)) + } + rbrace := p.expect(token.RBRACE) + p.expectSemi() + body := &ast.BlockStmt{lbrace, list, rbrace} + + if exprSwitch { + return &ast.SwitchStmt{pos, s1, p.makeExpr(s2), body} + } + // type switch + // TODO(gri): do all the checks! + return &ast.TypeSwitchStmt{pos, s1, s2, body} +} + +func (p *parser) parseCommClause() *ast.CommClause { + if p.trace { + defer un(trace(p, "CommClause")) + } + + p.openScope() + pos := p.pos + var comm ast.Stmt + if p.tok == token.CASE { + p.next() + lhs := p.parseLhsList() + if p.tok == token.ARROW { + // SendStmt + if len(lhs) > 1 { + p.errorExpected(lhs[0].Pos(), "1 expression") + // continue with first expression + } + arrow := p.pos + p.next() + rhs := p.parseRhs() + comm = &ast.SendStmt{lhs[0], arrow, rhs} + } else { + // RecvStmt + pos := p.pos + tok := p.tok + var rhs ast.Expr + if tok == token.ASSIGN || tok == token.DEFINE { + // RecvStmt with assignment + if len(lhs) > 2 { + p.errorExpected(lhs[0].Pos(), "1 or 2 expressions") + // continue with first two expressions + lhs = lhs[0:2] + } + p.next() + rhs = p.parseRhs() + } else { + // rhs must be single receive operation + if len(lhs) > 1 { + p.errorExpected(lhs[0].Pos(), "1 expression") + // continue with first expression + } + rhs = lhs[0] + lhs = nil // there is no lhs + } + if x, isUnary := rhs.(*ast.UnaryExpr); !isUnary || x.Op != token.ARROW { + p.errorExpected(rhs.Pos(), "send or receive operation") + rhs = &ast.BadExpr{rhs.Pos(), rhs.End()} + } + if lhs != nil { + comm = &ast.AssignStmt{lhs, pos, tok, []ast.Expr{rhs}} + } else { + comm = &ast.ExprStmt{rhs} + } + } + } else { + p.expect(token.DEFAULT) + } + + colon := p.expect(token.COLON) + body := p.parseStmtList() + p.closeScope() + + return &ast.CommClause{pos, comm, colon, body} +} + +func (p *parser) parseSelectStmt() *ast.SelectStmt { + if p.trace { + defer un(trace(p, "SelectStmt")) + } + + pos := p.expect(token.SELECT) + lbrace := p.expect(token.LBRACE) + var list []ast.Stmt + for p.tok == token.CASE || p.tok == token.DEFAULT { + list = append(list, p.parseCommClause()) + } + rbrace := p.expect(token.RBRACE) + p.expectSemi() + body := &ast.BlockStmt{lbrace, list, rbrace} + + return &ast.SelectStmt{pos, body} +} + +func (p *parser) parseForStmt() ast.Stmt { + if p.trace { + defer un(trace(p, "ForStmt")) + } + + pos := p.expect(token.FOR) + p.openScope() + defer p.closeScope() + + var s1, s2, s3 ast.Stmt + if p.tok != token.LBRACE { + prevLev := p.exprLev + p.exprLev = -1 + if p.tok != token.SEMICOLON { + s2 = p.parseSimpleStmt(false) + } + if p.tok == token.SEMICOLON { + p.next() + s1 = s2 + s2 = nil + if p.tok != token.SEMICOLON { + s2 = p.parseSimpleStmt(false) + } + p.expectSemi() + if p.tok != token.LBRACE { + s3 = p.parseSimpleStmt(false) + } + } + p.exprLev = prevLev + } + + body := p.parseBlockStmt() + p.expectSemi() + + if as, isAssign := s2.(*ast.AssignStmt); isAssign { + // possibly a for statement with a range clause; check assignment operator + if as.Tok != token.ASSIGN && as.Tok != token.DEFINE { + p.errorExpected(as.TokPos, "'=' or ':='") + return &ast.BadStmt{pos, body.End()} + } + // check lhs + var key, value ast.Expr + switch len(as.Lhs) { + case 2: + key, value = as.Lhs[0], as.Lhs[1] + case 1: + key = as.Lhs[0] + default: + p.errorExpected(as.Lhs[0].Pos(), "1 or 2 expressions") + return &ast.BadStmt{pos, body.End()} + } + // check rhs + if len(as.Rhs) != 1 { + p.errorExpected(as.Rhs[0].Pos(), "1 expression") + return &ast.BadStmt{pos, body.End()} + } + if rhs, isUnary := as.Rhs[0].(*ast.UnaryExpr); isUnary && rhs.Op == token.RANGE { + // rhs is range expression + // (any short variable declaration was handled by parseSimpleStat above) + return &ast.RangeStmt{pos, key, value, as.TokPos, as.Tok, rhs.X, body} + } + p.errorExpected(s2.Pos(), "range clause") + return &ast.BadStmt{pos, body.End()} + } + + // regular for statement + return &ast.ForStmt{pos, s1, p.makeExpr(s2), s3, body} +} + +func (p *parser) parseStmt() (s ast.Stmt) { + if p.trace { + defer un(trace(p, "Statement")) + } + + switch p.tok { + case token.CONST, token.TYPE, token.VAR: + s = &ast.DeclStmt{p.parseDecl()} + case + // tokens that may start a top-level expression + token.IDENT, token.INT, token.FLOAT, token.CHAR, token.STRING, token.FUNC, token.LPAREN, // operand + token.LBRACK, token.STRUCT, // composite type + token.MUL, token.AND, token.ARROW, token.ADD, token.SUB, token.XOR: // unary operators + s = p.parseSimpleStmt(true) + // because of the required look-ahead, labeled statements are + // parsed by parseSimpleStmt - don't expect a semicolon after + // them + if _, isLabeledStmt := s.(*ast.LabeledStmt); !isLabeledStmt { + p.expectSemi() + } + case token.GO: + s = p.parseGoStmt() + case token.DEFER: + s = p.parseDeferStmt() + case token.RETURN: + s = p.parseReturnStmt() + case token.BREAK, token.CONTINUE, token.GOTO, token.FALLTHROUGH: + s = p.parseBranchStmt(p.tok) + case token.LBRACE: + s = p.parseBlockStmt() + p.expectSemi() + case token.IF: + s = p.parseIfStmt() + case token.SWITCH: + s = p.parseSwitchStmt() + case token.SELECT: + s = p.parseSelectStmt() + case token.FOR: + s = p.parseForStmt() + case token.SEMICOLON: + s = &ast.EmptyStmt{p.pos} + p.next() + case token.RBRACE: + // a semicolon may be omitted before a closing "}" + s = &ast.EmptyStmt{p.pos} + default: + // no statement found + pos := p.pos + p.errorExpected(pos, "statement") + p.next() // make progress + s = &ast.BadStmt{pos, p.pos} + } + + return +} + +// ---------------------------------------------------------------------------- +// Declarations + +type parseSpecFunction func(p *parser, doc *ast.CommentGroup, iota int) ast.Spec + +func parseImportSpec(p *parser, doc *ast.CommentGroup, _ int) ast.Spec { + if p.trace { + defer un(trace(p, "ImportSpec")) + } + + var ident *ast.Ident + switch p.tok { + case token.PERIOD: + ident = &ast.Ident{p.pos, ".", nil} + p.next() + case token.IDENT: + ident = p.parseIdent() + } + + var path *ast.BasicLit + if p.tok == token.STRING { + path = &ast.BasicLit{p.pos, p.tok, p.lit} + p.next() + } else { + p.expect(token.STRING) // use expect() error handling + } + p.expectSemi() // call before accessing p.linecomment + + // collect imports + spec := &ast.ImportSpec{doc, ident, path, p.lineComment} + p.imports = append(p.imports, spec) + + return spec +} + +func parseConstSpec(p *parser, doc *ast.CommentGroup, iota int) ast.Spec { + if p.trace { + defer un(trace(p, "ConstSpec")) + } + + idents := p.parseIdentList() + typ := p.tryType() + var values []ast.Expr + if typ != nil || p.tok == token.ASSIGN || iota == 0 { + p.expect(token.ASSIGN) + values = p.parseRhsList() + } + p.expectSemi() // call before accessing p.linecomment + + // Go spec: The scope of a constant or variable identifier declared inside + // a function begins at the end of the ConstSpec or VarSpec and ends at + // the end of the innermost containing block. + // (Global identifiers are resolved in a separate phase after parsing.) + spec := &ast.ValueSpec{doc, idents, typ, values, p.lineComment} + p.declare(spec, p.topScope, ast.Con, idents...) + + return spec +} + +func parseTypeSpec(p *parser, doc *ast.CommentGroup, _ int) ast.Spec { + if p.trace { + defer un(trace(p, "TypeSpec")) + } + + ident := p.parseIdent() + + // Go spec: The scope of a type identifier declared inside a function begins + // at the identifier in the TypeSpec and ends at the end of the innermost + // containing block. + // (Global identifiers are resolved in a separate phase after parsing.) + spec := &ast.TypeSpec{doc, ident, nil, nil} + p.declare(spec, p.topScope, ast.Typ, ident) + + spec.Type = p.parseType() + p.expectSemi() // call before accessing p.linecomment + spec.Comment = p.lineComment + + return spec +} + +func parseVarSpec(p *parser, doc *ast.CommentGroup, _ int) ast.Spec { + if p.trace { + defer un(trace(p, "VarSpec")) + } + + idents := p.parseIdentList() + typ := p.tryType() + var values []ast.Expr + if typ == nil || p.tok == token.ASSIGN { + p.expect(token.ASSIGN) + values = p.parseRhsList() + } + p.expectSemi() // call before accessing p.linecomment + + // Go spec: The scope of a constant or variable identifier declared inside + // a function begins at the end of the ConstSpec or VarSpec and ends at + // the end of the innermost containing block. + // (Global identifiers are resolved in a separate phase after parsing.) + spec := &ast.ValueSpec{doc, idents, typ, values, p.lineComment} + p.declare(spec, p.topScope, ast.Var, idents...) + + return spec +} + +func (p *parser) parseGenDecl(keyword token.Token, f parseSpecFunction) *ast.GenDecl { + if p.trace { + defer un(trace(p, "GenDecl("+keyword.String()+")")) + } + + doc := p.leadComment + pos := p.expect(keyword) + var lparen, rparen token.Pos + var list []ast.Spec + if p.tok == token.LPAREN { + lparen = p.pos + p.next() + for iota := 0; p.tok != token.RPAREN && p.tok != token.EOF; iota++ { + list = append(list, f(p, p.leadComment, iota)) + } + rparen = p.expect(token.RPAREN) + p.expectSemi() + } else { + list = append(list, f(p, nil, 0)) + } + + return &ast.GenDecl{doc, pos, keyword, lparen, list, rparen} +} + +func (p *parser) parseReceiver(scope *ast.Scope) *ast.FieldList { + if p.trace { + defer un(trace(p, "Receiver")) + } + + pos := p.pos + par := p.parseParameters(scope, false) + + // must have exactly one receiver + if par.NumFields() != 1 { + p.errorExpected(pos, "exactly one receiver") + // TODO determine a better range for BadExpr below + par.List = []*ast.Field{&ast.Field{Type: &ast.BadExpr{pos, pos}}} + return par + } + + // recv type must be of the form ["*"] identifier + recv := par.List[0] + base := deref(recv.Type) + if _, isIdent := base.(*ast.Ident); !isIdent { + p.errorExpected(base.Pos(), "(unqualified) identifier") + par.List = []*ast.Field{&ast.Field{Type: &ast.BadExpr{recv.Pos(), recv.End()}}} + } + + return par +} + +func (p *parser) parseFuncDecl() *ast.FuncDecl { + if p.trace { + defer un(trace(p, "FunctionDecl")) + } + + doc := p.leadComment + pos := p.expect(token.FUNC) + scope := ast.NewScope(p.topScope) // function scope + + var recv *ast.FieldList + if p.tok == token.LPAREN { + recv = p.parseReceiver(scope) + } + + ident := p.parseIdent() + + params, results := p.parseSignature(scope) + + var body *ast.BlockStmt + if p.tok == token.LBRACE { + body = p.parseBody(scope) + } + p.expectSemi() + + decl := &ast.FuncDecl{doc, recv, ident, &ast.FuncType{pos, params, results}, body} + if recv == nil { + // Go spec: The scope of an identifier denoting a constant, type, + // variable, or function (but not method) declared at top level + // (outside any function) is the package block. + // + // init() functions cannot be referred to and there may + // be more than one - don't put them in the pkgScope + if ident.Name != "init" { + p.declare(decl, p.pkgScope, ast.Fun, ident) + } + } + + return decl +} + +func (p *parser) parseDecl() ast.Decl { + if p.trace { + defer un(trace(p, "Declaration")) + } + + var f parseSpecFunction + switch p.tok { + case token.CONST: + f = parseConstSpec + + case token.TYPE: + f = parseTypeSpec + + case token.VAR: + f = parseVarSpec + + case token.FUNC: + return p.parseFuncDecl() + + default: + pos := p.pos + p.errorExpected(pos, "declaration") + p.next() // make progress + decl := &ast.BadDecl{pos, p.pos} + return decl + } + + return p.parseGenDecl(p.tok, f) +} + +func (p *parser) parseDeclList() (list []ast.Decl) { + if p.trace { + defer un(trace(p, "DeclList")) + } + + for p.tok != token.EOF { + list = append(list, p.parseDecl()) + } + + return +} + +// ---------------------------------------------------------------------------- +// Source files + +func (p *parser) parseFile() *ast.File { + if p.trace { + defer un(trace(p, "File")) + } + + // package clause + doc := p.leadComment + pos := p.expect(token.PACKAGE) + // Go spec: The package clause is not a declaration; + // the package name does not appear in any scope. + ident := p.parseIdent() + if ident.Name == "_" { + p.error(p.pos, "invalid package name _") + } + p.expectSemi() + + var decls []ast.Decl + + // Don't bother parsing the rest if we had errors already. + // Likely not a Go source file at all. + + if p.ErrorCount() == 0 && p.mode&PackageClauseOnly == 0 { + // import decls + for p.tok == token.IMPORT { + decls = append(decls, p.parseGenDecl(token.IMPORT, parseImportSpec)) + } + + if p.mode&ImportsOnly == 0 { + // rest of package body + for p.tok != token.EOF { + decls = append(decls, p.parseDecl()) + } + } + } + + assert(p.topScope == p.pkgScope, "imbalanced scopes") + + // resolve global identifiers within the same file + i := 0 + for _, ident := range p.unresolved { + // i <= index for current ident + assert(ident.Obj == unresolved, "object already resolved") + ident.Obj = p.pkgScope.Lookup(ident.Name) // also removes unresolved sentinel + if ident.Obj == nil { + p.unresolved[i] = ident + i++ + } + } + + // TODO(gri): store p.imports in AST + return &ast.File{doc, pos, ident, decls, p.pkgScope, p.imports, p.unresolved[0:i], p.comments} +} diff --git a/src/pkg/go/printer/testdata/slow.golden b/src/pkg/go/printer/testdata/slow.golden new file mode 100644 index 000000000..43a15cb1d --- /dev/null +++ b/src/pkg/go/printer/testdata/slow.golden @@ -0,0 +1,85 @@ +// Copyright 2011 The Go Authors. All rights reserved. +// Use of this source code is governed by a BSD-style +// license that can be found in the LICENSE file. + +package deepequal_test + +import ( + "testing" + "google3/spam/archer/frontend/deepequal" +) + +func TestTwoNilValues(t *testing.T) { + if err := deepequal.Check(nil, nil); err != nil { + t.Errorf("expected nil, saw %v", err) + } +} + +type Foo struct { + bar *Bar + bang *Bar +} + +type Bar struct { + baz *Baz + foo []*Foo +} + +type Baz struct { + entries map[int]interface{} + whatever string +} + +func newFoo() *Foo { + return &Foo{bar: &Bar{baz: &Baz{ + entries: map[int]interface{}{ + 42: &Foo{}, + 21: &Bar{}, + 11: &Baz{whatever: "it's just a test"}}}}, + bang: &Bar{foo: []*Foo{ + &Foo{bar: &Bar{baz: &Baz{ + entries: map[int]interface{}{ + 43: &Foo{}, + 22: &Bar{}, + 13: &Baz{whatever: "this is nuts"}}}}, + bang: &Bar{foo: []*Foo{ + &Foo{bar: &Bar{baz: &Baz{ + entries: map[int]interface{}{ + 61: &Foo{}, + 71: &Bar{}, + 11: &Baz{whatever: "no, it's Go"}}}}, + bang: &Bar{foo: []*Foo{ + &Foo{bar: &Bar{baz: &Baz{ + entries: map[int]interface{}{ + 0: &Foo{}, + -2: &Bar{}, + -11: &Baz{whatever: "we need to go deeper"}}}}, + bang: &Bar{foo: []*Foo{ + &Foo{bar: &Bar{baz: &Baz{ + entries: map[int]interface{}{ + -2: &Foo{}, + -5: &Bar{}, + -7: &Baz{whatever: "are you serious?"}}}}, + bang: &Bar{foo: []*Foo{}}}, + &Foo{bar: &Bar{baz: &Baz{ + entries: map[int]interface{}{ + -100: &Foo{}, + 50: &Bar{}, + 20: &Baz{whatever: "na, not really ..."}}}}, + bang: &Bar{foo: []*Foo{}}}}}}}}}, + &Foo{bar: &Bar{baz: &Baz{ + entries: map[int]interface{}{ + 2: &Foo{}, + 1: &Bar{}, + -1: &Baz{whatever: "... it's just a test."}}}}, + bang: &Bar{foo: []*Foo{}}}}}}}}} +} + +func TestElaborate(t *testing.T) { + a := newFoo() + b := newFoo() + + if err := deepequal.Check(a, b); err != nil { + t.Errorf("expected nil, saw %v", err) + } +} diff --git a/src/pkg/go/printer/testdata/slow.input b/src/pkg/go/printer/testdata/slow.input new file mode 100644 index 000000000..0e5a23d88 --- /dev/null +++ b/src/pkg/go/printer/testdata/slow.input @@ -0,0 +1,85 @@ +// Copyright 2011 The Go Authors. All rights reserved. +// Use of this source code is governed by a BSD-style +// license that can be found in the LICENSE file. + +package deepequal_test + +import ( + "testing" + "google3/spam/archer/frontend/deepequal" +) + +func TestTwoNilValues(t *testing.T) { + if err := deepequal.Check(nil, nil); err != nil { + t.Errorf("expected nil, saw %v", err) + } +} + +type Foo struct { + bar *Bar + bang *Bar +} + +type Bar struct { + baz *Baz + foo []*Foo +} + +type Baz struct { + entries map[int]interface{} + whatever string +} + +func newFoo() (*Foo) { +return &Foo{bar: &Bar{ baz: &Baz{ +entries: map[int]interface{}{ +42: &Foo{}, +21: &Bar{}, +11: &Baz{ whatever: "it's just a test" }}}}, + bang: &Bar{foo: []*Foo{ +&Foo{bar: &Bar{ baz: &Baz{ +entries: map[int]interface{}{ +43: &Foo{}, +22: &Bar{}, +13: &Baz{ whatever: "this is nuts" }}}}, + bang: &Bar{foo: []*Foo{ +&Foo{bar: &Bar{ baz: &Baz{ +entries: map[int]interface{}{ +61: &Foo{}, +71: &Bar{}, +11: &Baz{ whatever: "no, it's Go" }}}}, + bang: &Bar{foo: []*Foo{ +&Foo{bar: &Bar{ baz: &Baz{ +entries: map[int]interface{}{ +0: &Foo{}, +-2: &Bar{}, +-11: &Baz{ whatever: "we need to go deeper" }}}}, + bang: &Bar{foo: []*Foo{ +&Foo{bar: &Bar{ baz: &Baz{ +entries: map[int]interface{}{ +-2: &Foo{}, +-5: &Bar{}, +-7: &Baz{ whatever: "are you serious?" }}}}, + bang: &Bar{foo: []*Foo{}}}, +&Foo{bar: &Bar{ baz: &Baz{ +entries: map[int]interface{}{ +-100: &Foo{}, +50: &Bar{}, +20: &Baz{ whatever: "na, not really ..." }}}}, + bang: &Bar{foo: []*Foo{}}}}}}}}}, +&Foo{bar: &Bar{ baz: &Baz{ +entries: map[int]interface{}{ +2: &Foo{}, +1: &Bar{}, +-1: &Baz{ whatever: "... it's just a test." }}}}, + bang: &Bar{foo: []*Foo{}}}}}}}}} +} + +func TestElaborate(t *testing.T) { + a := newFoo() + b := newFoo() + + if err := deepequal.Check(a, b); err != nil { + t.Errorf("expected nil, saw %v", err) + } +} diff --git a/src/pkg/go/printer/testdata/statements.golden b/src/pkg/go/printer/testdata/statements.golden new file mode 100644 index 000000000..a6d85107f --- /dev/null +++ b/src/pkg/go/printer/testdata/statements.golden @@ -0,0 +1,412 @@ +// Copyright 2009 The Go Authors. All rights reserved. +// Use of this source code is governed by a BSD-style +// license that can be found in the LICENSE file. + +package statements + +var expr bool + +func use(x interface{}) {} + +// Formatting of if-statement headers. +func _() { + if true { + } + if true { + } // no semicolon printed + if expr { + } + if expr { + } // no semicolon printed + if expr { + } // no parens printed + if expr { + } // no semicolon and parens printed + if x := expr; true { + use(x) + } + if x := expr; expr { + use(x) + } +} + +// Formatting of switch-statement headers. +func _() { + switch { + } + switch { + } // no semicolon printed + switch expr { + } + switch expr { + } // no semicolon printed + switch expr { + } // no parens printed + switch expr { + } // no semicolon and parens printed + switch x := expr; { + default: + use( + x) + } + switch x := expr; expr { + default: + use(x) + } +} + +// Formatting of switch statement bodies. +func _() { + switch { + } + + switch x := 0; x { + case 1: + use(x) + use(x) // followed by an empty line + + case 2: // followed by an empty line + + use(x) // followed by an empty line + + case 3: // no empty lines + use(x) + use(x) + } + + switch x { + case 0: + use(x) + case 1: // this comment should have no effect on the previous or next line + use(x) + } + + switch x := 0; x { + case 1: + x = 0 + // this comment should be indented + case 2: + x = 0 + // this comment should not be indented, it is aligned with the next case + case 3: + x = 0 + /* indented comment + aligned + aligned + */ + // bla + /* and more */ + case 4: + x = 0 + /* not indented comment + aligned + aligned + */ + // bla + /* and more */ + case 5: + } +} + +// Formatting of selected select statements. +func _() { + select {} + select { /* this comment should not be tab-aligned because the closing } is on the same line */ + } + select { /* this comment should be tab-aligned */ + } + select { // this comment should be tab-aligned + } + select { + case <-c: + } +} + +// Formatting of for-statement headers. +func _() { + for { + } + for expr { + } + for expr { + } // no parens printed + for { + } // no semicolons printed + for x := expr; ; { + use(x) + } + for expr { + } // no semicolons printed + for expr { + } // no semicolons and parens printed + for ; ; expr = false { + } + for x := expr; expr; { + use(x) + } + for x := expr; ; expr = false { + use(x) + } + for ; expr; expr = false { + } + for x := expr; expr; expr = false { + use(x) + } + for x := range []int{} { + use(x) + } + for x := range []int{} { + use(x) + } // no parens printed +} + +// Don't remove mandatory parentheses around composite literals in control clauses. +func _() { + // strip parentheses - no composite literals or composite literals don't start with a type name + if x { + } + if x { + } + if []T{} { + } + if []T{} { + } + if []T{} { + } + + for x { + } + for x { + } + for []T{} { + } + for []T{} { + } + for []T{} { + } + + switch x { + } + switch x { + } + switch []T{} { + } + switch []T{} { + } + + for _ = range []T{T{42}} { + } + + // leave parentheses - composite literals start with a type name + if (T{}) { + } + if (T{}) { + } + if (T{}) { + } + + for (T{}) { + } + for (T{}) { + } + for (T{}) { + } + + switch (T{}) { + } + switch (T{}) { + } + + for _ = range (T1{T{42}}) { + } + + if x == (T{42}[0]) { + } + if (x == T{42}[0]) { + } + if x == (T{42}[0]) { + } + if x == (T{42}[0]) { + } + if x == (T{42}[0]) { + } + if x == a+b*(T{42}[0]) { + } + if (x == a+b*T{42}[0]) { + } + if x == a+b*(T{42}[0]) { + } + if x == a+(b * (T{42}[0])) { + } + if x == a+b*(T{42}[0]) { + } + if (a + b*(T{42}[0])) == x { + } + if (a + b*(T{42}[0])) == x { + } + + if struct{ x bool }{false}.x { + } + if (struct{ x bool }{false}.x) == false { + } + if struct{ x bool }{false}.x == false { + } +} + +// Extra empty lines inside functions. Do respect source code line +// breaks between statement boundaries but print at most one empty +// line at a time. +func _() { + + const _ = 0 + + const _ = 1 + type _ int + type _ float + + var _ = 0 + var x = 1 + + // Each use(x) call below should have at most one empty line before and after. + // Known bug: The first use call may have more than one empty line before + // (see go/printer/nodes.go, func linebreak). + + + use(x) + + if x < x { + + use(x) + + } else { + + use(x) + + } +} + +// Formatting around labels. +func _() { +L: +} + +func _() { + // this comment should be indented +L: // no semicolon needed +} + +func _() { + switch 0 { + case 0: + L0: + ; // semicolon required + case 1: + L1: + ; // semicolon required + default: + L2: // no semicolon needed + } +} + +func _() { + f() +L1: + f() +L2: + ; +L3: +} + +func _() { + // this comment should be indented +L: +} + +func _() { +L: + _ = 0 +} + +func _() { + // this comment should be indented +L: + _ = 0 +} + +func _() { + for { + L1: + _ = 0 + L2: + _ = 0 + } +} + +func _() { + // this comment should be indented + for { + L1: + _ = 0 + L2: + _ = 0 + } +} + +func _() { + if true { + _ = 0 + } + _ = 0 // the indentation here should not be affected by the long label name +AnOverlongLabel: + _ = 0 + + if true { + _ = 0 + } + _ = 0 + +L: + _ = 0 +} + +func _() { + for { + goto L + } +L: + + MoreCode() +} + +func _() { + for { + goto L + } +L: // A comment on the same line as the label, followed by a single empty line. + // Known bug: There may be more than one empty line before MoreCode() + // (see go/printer/nodes.go, func linebreak). + + + MoreCode() +} + +func _() { + for { + goto L + } +L: + + // There should be a single empty line before this comment. + MoreCode() +} + +func _() { + for { + goto AVeryLongLabelThatShouldNotAffectFormatting + } +AVeryLongLabelThatShouldNotAffectFormatting: + // There should be a single empty line after this comment. + + // There should be a single empty line before this comment. + MoreCode() +} diff --git a/src/pkg/go/printer/testdata/statements.input b/src/pkg/go/printer/testdata/statements.input new file mode 100644 index 000000000..86a753c5a --- /dev/null +++ b/src/pkg/go/printer/testdata/statements.input @@ -0,0 +1,351 @@ +// Copyright 2009 The Go Authors. All rights reserved. +// Use of this source code is governed by a BSD-style +// license that can be found in the LICENSE file. + +package statements + +var expr bool + +func use(x interface{}) {} + +// Formatting of if-statement headers. +func _() { + if true {} + if; true {} // no semicolon printed + if expr{} + if;expr{} // no semicolon printed + if (expr){} // no parens printed + if;((expr)){} // no semicolon and parens printed + if x:=expr;true{ + use(x)} + if x:=expr; expr {use(x)} +} + + +// Formatting of switch-statement headers. +func _() { + switch {} + switch;{} // no semicolon printed + switch expr {} + switch;expr{} // no semicolon printed + switch (expr) {} // no parens printed + switch;((expr)){} // no semicolon and parens printed + switch x := expr; { default:use( +x) + } + switch x := expr; expr {default:use(x)} +} + + +// Formatting of switch statement bodies. +func _() { + switch { + } + + switch x := 0; x { + case 1: + use(x) + use(x) // followed by an empty line + + case 2: // followed by an empty line + + use(x) // followed by an empty line + + case 3: // no empty lines + use(x) + use(x) + } + + switch x { + case 0: + use(x) + case 1: // this comment should have no effect on the previous or next line + use(x) + } + + switch x := 0; x { + case 1: + x = 0 + // this comment should be indented + case 2: + x = 0 + // this comment should not be indented, it is aligned with the next case + case 3: + x = 0 + /* indented comment + aligned + aligned + */ + // bla + /* and more */ + case 4: + x = 0 + /* not indented comment + aligned + aligned + */ + // bla + /* and more */ + case 5: + } +} + + +// Formatting of selected select statements. +func _() { + select { + } + select { /* this comment should not be tab-aligned because the closing } is on the same line */ } + select { /* this comment should be tab-aligned */ + } + select { // this comment should be tab-aligned + } + select { case <-c: } +} + + +// Formatting of for-statement headers. +func _() { + for{} + for expr {} + for (expr) {} // no parens printed + for;;{} // no semicolons printed + for x :=expr;; {use( x)} + for; expr;{} // no semicolons printed + for; ((expr));{} // no semicolons and parens printed + for; ; expr = false {} + for x :=expr; expr; {use(x)} + for x := expr;; expr=false {use(x)} + for;expr;expr =false { + } + for x := expr;expr;expr = false { use(x) } + for x := range []int{} { use(x) } + for x := range (([]int{})) { use(x) } // no parens printed +} + + +// Don't remove mandatory parentheses around composite literals in control clauses. +func _() { + // strip parentheses - no composite literals or composite literals don't start with a type name + if (x) {} + if (((x))) {} + if ([]T{}) {} + if (([]T{})) {} + if ; (((([]T{})))) {} + + for (x) {} + for (((x))) {} + for ([]T{}) {} + for (([]T{})) {} + for ; (((([]T{})))) ; {} + + switch (x) {} + switch (((x))) {} + switch ([]T{}) {} + switch ; (((([]T{})))) {} + + for _ = range ((([]T{T{42}}))) {} + + // leave parentheses - composite literals start with a type name + if (T{}) {} + if ((T{})) {} + if ; ((((T{})))) {} + + for (T{}) {} + for ((T{})) {} + for ; ((((T{})))) ; {} + + switch (T{}) {} + switch ; ((((T{})))) {} + + for _ = range (((T1{T{42}}))) {} + + if x == (T{42}[0]) {} + if (x == T{42}[0]) {} + if (x == (T{42}[0])) {} + if (x == (((T{42}[0])))) {} + if (((x == (T{42}[0])))) {} + if x == a + b*(T{42}[0]) {} + if (x == a + b*T{42}[0]) {} + if (x == a + b*(T{42}[0])) {} + if (x == a + ((b * (T{42}[0])))) {} + if (((x == a + b * (T{42}[0])))) {} + if (((a + b * (T{42}[0])) == x)) {} + if (((a + b * (T{42}[0])))) == x {} + + if (struct{x bool}{false}.x) {} + if (struct{x bool}{false}.x) == false {} + if (struct{x bool}{false}.x == false) {} +} + + +// Extra empty lines inside functions. Do respect source code line +// breaks between statement boundaries but print at most one empty +// line at a time. +func _() { + + const _ = 0 + + const _ = 1 + type _ int + type _ float + + var _ = 0 + var x = 1 + + // Each use(x) call below should have at most one empty line before and after. + // Known bug: The first use call may have more than one empty line before + // (see go/printer/nodes.go, func linebreak). + + + + use(x) + + if x < x { + + use(x) + + } else { + + use(x) + + } +} + + +// Formatting around labels. +func _() { + L: +} + + +func _() { + // this comment should be indented + L: ; // no semicolon needed +} + + +func _() { + switch 0 { + case 0: + L0: ; // semicolon required + case 1: + L1: ; // semicolon required + default: + L2: ; // no semicolon needed + } +} + + +func _() { + f() +L1: + f() +L2: + ; +L3: +} + + +func _() { + // this comment should be indented + L: +} + + +func _() { + L: _ = 0 +} + + +func _() { + // this comment should be indented + L: _ = 0 +} + + +func _() { + for { + L1: _ = 0 + L2: + _ = 0 + } +} + + +func _() { + // this comment should be indented + for { + L1: _ = 0 + L2: + _ = 0 + } +} + + +func _() { + if true { + _ = 0 + } + _ = 0 // the indentation here should not be affected by the long label name +AnOverlongLabel: + _ = 0 + + if true { + _ = 0 + } + _ = 0 + +L: _ = 0 +} + + +func _() { + for { + goto L + } +L: + + MoreCode() +} + + +func _() { + for { + goto L + } +L: // A comment on the same line as the label, followed by a single empty line. + // Known bug: There may be more than one empty line before MoreCode() + // (see go/printer/nodes.go, func linebreak). + + + + + MoreCode() +} + + +func _() { + for { + goto L + } +L: + + + + + // There should be a single empty line before this comment. + MoreCode() +} + + +func _() { + for { + goto AVeryLongLabelThatShouldNotAffectFormatting + } +AVeryLongLabelThatShouldNotAffectFormatting: + // There should be a single empty line after this comment. + + // There should be a single empty line before this comment. + MoreCode() +} |