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-rw-r--r--src/cmd/gofmt/gofmt.go4
-rw-r--r--src/pkg/go/ast/ast.go4
-rw-r--r--src/pkg/go/parser/parser.go66
-rw-r--r--src/pkg/go/printer/printer.go76
-rw-r--r--src/pkg/go/printer/testdata/golden1.go15
-rw-r--r--src/pkg/go/printer/testdata/source1.go21
6 files changed, 150 insertions, 36 deletions
diff --git a/src/cmd/gofmt/gofmt.go b/src/cmd/gofmt/gofmt.go
index b1e8b5061..503cd4641 100644
--- a/src/cmd/gofmt/gofmt.go
+++ b/src/cmd/gofmt/gofmt.go
@@ -38,6 +38,7 @@ var (
usespaces = flag.Bool("spaces", false, "align with blanks instead of tabs");
optcommas = flag.Bool("optcommas", false, "print optional commas");
optsemis = flag.Bool("optsemis", false, "print optional semicolons");
+ reverse = flag.Bool("reverse", false, "print top-level declarations in reverse order without forward-declarations");
)
@@ -116,6 +117,9 @@ func printerMode() uint {
if *optsemis {
mode |= printer.OptSemis;
}
+ if *reverse {
+ mode |= printer.Reverse;
+ }
return mode;
}
diff --git a/src/pkg/go/ast/ast.go b/src/pkg/go/ast/ast.go
index cc1d69213..2e606b942 100644
--- a/src/pkg/go/ast/ast.go
+++ b/src/pkg/go/ast/ast.go
@@ -219,7 +219,7 @@ type (
//
TypeAssertExpr struct {
X Expr; // expression
- Type Expr; // asserted type
+ Type Expr; // asserted type; nil means type switch X.(type)
};
// A CallExpr node represents an expression followed by an argument list.
@@ -546,7 +546,7 @@ type (
// A TypeCaseClause represents a case of a type switch statement.
TypeCaseClause struct {
token.Position; // position of "case" or "default" keyword
- Type Expr; // nil means default case
+ Types []Expr; // nil means default case
Colon token.Position; // position of ":"
Body []Stmt; // statement list; or nil
};
diff --git a/src/pkg/go/parser/parser.go b/src/pkg/go/parser/parser.go
index 270403aac..f0fa487cc 100644
--- a/src/pkg/go/parser/parser.go
+++ b/src/pkg/go/parser/parser.go
@@ -952,8 +952,7 @@ func (p *parser) parseSelectorOrTypeAssertion(x ast.Expr) ast.Expr {
p.expect(token.LPAREN);
var typ ast.Expr;
if p.tok == token.TYPE {
- // special case for type switch
- typ = &ast.Ident{p.pos, "type"};
+ // type switch: typ == nil
p.next();
} else {
typ = p.parseType();
@@ -1078,6 +1077,11 @@ func (p *parser) checkExpr(x ast.Expr) ast.Expr {
case *ast.SelectorExpr:
case *ast.IndexExpr:
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()};
+ }
case *ast.CallExpr:
case *ast.StarExpr:
case *ast.UnaryExpr:
@@ -1353,15 +1357,6 @@ func (p *parser) parseBranchStmt(tok token.Token) *ast.BranchStmt {
}
-func (p *parser) isExpr(s ast.Stmt) bool {
- if s == nil {
- return true;
- }
- dummy, isExpr := s.(*ast.ExprStmt);
- return isExpr;
-}
-
-
func (p *parser) makeExpr(s ast.Stmt) ast.Expr {
if s == nil {
return nil;
@@ -1411,7 +1406,7 @@ func (p *parser) parseIfStmt() *ast.IfStmt {
}
pos := p.expect(token.IF);
- s1, s2, dummy := p.parseControlClause(false);
+ s1, s2, _ := p.parseControlClause(false);
body := p.parseBlockStmt();
var else_ ast.Stmt;
if p.tok == token.ELSE {
@@ -1445,6 +1440,28 @@ func (p *parser) parseCaseClause() *ast.CaseClause {
}
+func (p *parser) parseTypeList() []ast.Expr {
+ if p.trace {
+ defer un(trace(p, "TypeList"));
+ }
+
+ list := vector.New(0);
+ list.Push(p.parseType());
+ for p.tok == token.COMMA {
+ p.next();
+ list.Push(p.parseType());
+ }
+
+ // convert list
+ exprs := make([]ast.Expr, list.Len());
+ for i := 0; i < list.Len(); i++ {
+ exprs[i] = list.At(i).(ast.Expr);
+ }
+
+ return exprs;
+}
+
+
func (p *parser) parseTypeCaseClause() *ast.TypeCaseClause {
if p.trace {
defer un(trace(p, "TypeCaseClause"));
@@ -1452,10 +1469,10 @@ func (p *parser) parseTypeCaseClause() *ast.TypeCaseClause {
// TypeSwitchCase
pos := p.pos;
- var typ ast.Expr;
+ var types []ast.Expr;
if p.tok == token.CASE {
p.next();
- typ = p.parseType();
+ types = p.parseTypeList();
} else {
p.expect(token.DEFAULT);
}
@@ -1463,7 +1480,21 @@ func (p *parser) parseTypeCaseClause() *ast.TypeCaseClause {
colon := p.expect(token.COLON);
body := p.parseStmtList();
- return &ast.TypeCaseClause{pos, typ, colon, body};
+ return &ast.TypeCaseClause{pos, types, 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;
}
@@ -1473,10 +1504,9 @@ func (p *parser) parseSwitchStmt() ast.Stmt {
}
pos := p.expect(token.SWITCH);
- s1, s2, dummy := p.parseControlClause(false);
+ s1, s2, _ := p.parseControlClause(false);
- if p.isExpr(s2) {
- // expression switch
+ if isExprSwitch(s2) {
lbrace := p.expect(token.LBRACE);
cases := vector.New(0);
for p.tok == token.CASE || p.tok == token.DEFAULT {
diff --git a/src/pkg/go/printer/printer.go b/src/pkg/go/printer/printer.go
index b2d34ef5c..d863c01c3 100644
--- a/src/pkg/go/printer/printer.go
+++ b/src/pkg/go/printer/printer.go
@@ -32,6 +32,7 @@ const (
UseSpaces; // use spaces instead of tabs for indentation and alignment
OptCommas; // print optional commas
OptSemis; // print optional semicolons
+ Reverse; // print top-level declarations in reverse order without forward-declarations
)
@@ -682,7 +683,11 @@ func (p *printer) expr1(expr ast.Expr, prec1 int) (optSemi bool) {
case *ast.TypeAssertExpr:
p.expr1(x.X, token.HighestPrec);
p.print(token.PERIOD, token.LPAREN);
- p.expr(x.Type);
+ if x.Type != nil {
+ p.expr(x.Type);
+ } else {
+ p.print(token.TYPE);
+ }
p.print(token.RPAREN);
case *ast.IndexExpr:
@@ -722,6 +727,10 @@ func (p *printer) expr1(expr ast.Expr, prec1 int) (optSemi bool) {
p.expr(x.Elt);
case *ast.StructType:
+ if x.Fields == nil && p.mode & Reverse != 0 && p.level == 0 {
+ // omit top-level forward declarations in reverse mode
+ return true;
+ }
p.print(token.STRUCT);
optSemi = p.fieldList(x.Lbrace, x.Fields, x.Rbrace, false);
@@ -730,6 +739,10 @@ func (p *printer) expr1(expr ast.Expr, prec1 int) (optSemi bool) {
p.signature(x.Params, x.Results);
case *ast.InterfaceType:
+ if x.Methods == nil && p.mode & Reverse != 0 && p.level == 0 {
+ // omit top-level forward declarations in reverse mode
+ return true;
+ }
p.print(token.INTERFACE);
optSemi = p.fieldList(x.Lbrace, x.Methods, x.Rbrace, true);
@@ -941,9 +954,9 @@ func (p *printer) stmt(stmt ast.Stmt) (optSemi bool) {
optSemi = true;
case *ast.TypeCaseClause:
- if s.Type != nil {
+ if s.Types != nil {
p.print(token.CASE, blank);
- p.expr(s.Type);
+ p.exprList(s.Types);
} else {
p.print(token.DEFAULT);
}
@@ -1070,13 +1083,25 @@ func (p *printer) decl(decl ast.Decl) (comment *ast.CommentGroup, optSemi bool)
p.print(d.Lparen, token.LPAREN);
if len(d.Specs) > 0 {
p.print(+1, newline);
- for i, s := range d.Specs {
- if i > 0 {
- p.print(token.SEMICOLON);
- p.lineComment(comment);
- p.print(newline);
+ if p.mode & Reverse != 0 && p.level == 0 {
+ for i := len(d.Specs)-1; i >= 0; i-- {
+ s := d.Specs[i];
+ if i < len(d.Specs)-1 {
+ p.print(token.SEMICOLON);
+ p.lineComment(comment);
+ p.print(newline);
+ }
+ comment, optSemi = p.spec(s);
+ }
+ } else {
+ for i, s := range d.Specs {
+ if i > 0 {
+ p.print(token.SEMICOLON);
+ p.lineComment(comment);
+ p.print(newline);
+ }
+ comment, optSemi = p.spec(s);
}
- comment, optSemi = p.spec(s);
}
if p.optSemis() {
p.print(token.SEMICOLON);
@@ -1094,6 +1119,10 @@ func (p *printer) decl(decl ast.Decl) (comment *ast.CommentGroup, optSemi bool)
}
case *ast.FuncDecl:
+ if d.Body == nil && p.mode & Reverse != 0 {
+ // omit forward declarations in reverse mode
+ break;
+ }
p.leadComment(d.Doc);
p.print(lineTag(d.Pos()), token.FUNC, blank);
if recv := d.Recv; recv != nil {
@@ -1131,13 +1160,25 @@ func (p *printer) file(src *ast.File) {
p.print(src.Pos(), token.PACKAGE, blank);
p.expr(src.Name);
- for _, d := range src.Decls {
- p.print(newline, newline);
- comment, _ := p.decl(d);
- if p.optSemis() {
- p.print(token.SEMICOLON);
+ if p.mode & Reverse != 0 {
+ for i := len(src.Decls)-1; i >= 0; i-- {
+ d := src.Decls[i];
+ p.print(newline, newline);
+ comment, _ := p.decl(d);
+ if p.optSemis() {
+ p.print(token.SEMICOLON);
+ }
+ p.lineComment(comment);
+ }
+ } else {
+ for _, d := range src.Decls {
+ p.print(newline, newline);
+ comment, _ := p.decl(d);
+ if p.optSemis() {
+ p.print(token.SEMICOLON);
+ }
+ p.lineComment(comment);
}
- p.lineComment(comment);
}
p.print(newline);
@@ -1181,7 +1222,10 @@ func Fprint(output io.Writer, node interface{}, mode uint, tabwidth int) (int, o
comment, _ := p.decl(n);
p.lineComment(comment); // no newline at end
case *ast.File:
- p.comment = n.Comments;
+ if mode & Reverse == 0 {
+ // don't print comments in reverse mode
+ p.comment = n.Comments;
+ }
p.file(n);
default:
p.errors <- os.NewError("unsupported node type");
diff --git a/src/pkg/go/printer/testdata/golden1.go b/src/pkg/go/printer/testdata/golden1.go
index b36497f25..084c65d28 100644
--- a/src/pkg/go/printer/testdata/golden1.go
+++ b/src/pkg/go/printer/testdata/golden1.go
@@ -57,3 +57,18 @@ func abs(x int) int {
}
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 bool, int, float:
+ case string:
+ default:
+ }
+}
diff --git a/src/pkg/go/printer/testdata/source1.go b/src/pkg/go/printer/testdata/source1.go
index b0a9c71eb..162f00005 100644
--- a/src/pkg/go/printer/testdata/source1.go
+++ b/src/pkg/go/printer/testdata/source1.go
@@ -58,3 +58,24 @@ func abs(x int) int {
}
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 bool, int, float:
+ case string:
+ default:
+ }
+}
generated by cgit v1.2.3 (git 2.39.1) at 2025-05-23 01:17:42 +0000