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path: root/src/pkg/go/parser/parser.go
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Diffstat (limited to 'src/pkg/go/parser/parser.go')
-rw-r--r--src/pkg/go/parser/parser.go124
1 files changed, 54 insertions, 70 deletions
diff --git a/src/pkg/go/parser/parser.go b/src/pkg/go/parser/parser.go
index be82b2f80..6bee8de9f 100644
--- a/src/pkg/go/parser/parser.go
+++ b/src/pkg/go/parser/parser.go
@@ -16,19 +16,6 @@ import (
"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
- SpuriousErrors // report all (not just the first) errors per line
-)
-
// The parser structure holds the parser's internal state.
type parser struct {
file *token.File
@@ -36,7 +23,7 @@ type parser struct {
scanner scanner.Scanner
// Tracing/debugging
- mode uint // parsing mode
+ mode Mode // parsing mode
trace bool // == (mode & Trace != 0)
indent uint // indentation used for tracing output
@@ -65,18 +52,13 @@ type parser struct {
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
+func (p *parser) init(fset *token.FileSet, filename string, src []byte, mode Mode) {
+ p.file = fset.AddFile(filename, fset.Base(), len(src))
+ var m scanner.Mode
if mode&ParseComments != 0 {
- m |= scanner.ScanComments
+ 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.scanner.Init(p.file, src, p, m)
p.mode = mode
p.trace = mode&Trace != 0 // for convenience (p.trace is used frequently)
@@ -92,6 +74,14 @@ func (p *parser) init(fset *token.FileSet, filename string, src []byte, mode uin
p.openLabelScope()
}
+func (p *parser) errors() error {
+ m := scanner.Sorted
+ if p.mode&SpuriousErrors == 0 {
+ m = scanner.NoMultiples
+ }
+ return p.GetError(m)
+}
+
// ----------------------------------------------------------------------------
// Scoping support
@@ -144,28 +134,31 @@ func (p *parser) declare(decl, data interface{}, scope *ast.Scope, kind ast.ObjK
}
}
-func (p *parser) shortVarDecl(idents []*ast.Ident) {
+func (p *parser) shortVarDecl(decl *ast.AssignStmt, list []ast.Expr) {
// 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")
- 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
- ident.Obj = obj
- if ident.Name != "_" {
- if alt := p.topScope.Insert(obj); alt != nil {
- ident.Obj = alt // redeclaration
- } else {
- n++ // new declaration
+ for _, x := range list {
+ if ident, isIdent := x.(*ast.Ident); isIdent {
+ assert(ident.Obj == nil, "identifier already declared or resolved")
+ obj := ast.NewObj(ast.Var, ident.Name)
+ // remember corresponding assignment for other tools
+ obj.Decl = decl
+ ident.Obj = obj
+ if ident.Name != "_" {
+ if alt := p.topScope.Insert(obj); alt != nil {
+ ident.Obj = alt // redeclaration
+ } else {
+ n++ // new declaration
+ }
}
+ } else {
+ p.errorExpected(x.Pos(), "identifier")
}
}
if n == 0 && p.mode&DeclarationErrors != 0 {
- p.error(idents[0].Pos(), "no new variables on left side of :=")
+ p.error(list[0].Pos(), "no new variables on left side of :=")
}
}
@@ -434,7 +427,9 @@ func (p *parser) parseLhsList() []ast.Expr {
switch p.tok {
case token.DEFINE:
// lhs of a short variable declaration
- p.shortVarDecl(p.makeIdentList(list))
+ // but doesn't enter scope until later:
+ // caller must call p.shortVarDecl(p.makeIdentList(list))
+ // at appropriate time.
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
@@ -520,7 +515,7 @@ func (p *parser) makeIdentList(list []ast.Expr) []*ast.Ident {
for i, x := range list {
ident, isIdent := x.(*ast.Ident)
if !isIdent {
- pos := x.(ast.Expr).Pos()
+ pos := x.Pos()
p.errorExpected(pos, "identifier")
ident = &ast.Ident{pos, "_", nil}
}
@@ -1129,7 +1124,7 @@ func (p *parser) parseLiteralValue(typ ast.Expr) ast.Expr {
// 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) {
+ switch unparen(x).(type) {
case *ast.BadExpr:
case *ast.Ident:
case *ast.BasicLit:
@@ -1398,7 +1393,11 @@ func (p *parser) parseSimpleStmt(mode int) (ast.Stmt, bool) {
} else {
y = p.parseRhsList()
}
- return &ast.AssignStmt{x, pos, tok, y}, isRange
+ as := &ast.AssignStmt{x, pos, tok, y}
+ if tok == token.DEFINE {
+ p.shortVarDecl(as, x)
+ }
+ return as, isRange
}
if len(x) > 1 {
@@ -1710,31 +1709,28 @@ func (p *parser) parseCommClause() *ast.CommClause {
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 {
+ if tok := p.tok; 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]
}
+ pos := p.pos
p.next()
- rhs = p.parseRhs()
+ rhs := p.parseRhs()
+ as := &ast.AssignStmt{lhs, pos, tok, []ast.Expr{rhs}}
+ if tok == token.DEFINE {
+ p.shortVarDecl(as, lhs)
+ }
+ comm = as
} else {
- // rhs must be single receive operation
+ // lhs 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 lhs != nil {
- comm = &ast.AssignStmt{lhs, pos, tok, []ast.Expr{rhs}}
- } else {
- comm = &ast.ExprStmt{rhs}
+ comm = &ast.ExprStmt{lhs[0]}
}
}
} else {
@@ -1909,7 +1905,7 @@ func parseImportSpec(p *parser, doc *ast.CommentGroup, _ int) ast.Spec {
p.expectSemi() // call before accessing p.linecomment
// collect imports
- spec := &ast.ImportSpec{doc, ident, path, p.lineComment}
+ spec := &ast.ImportSpec{doc, ident, path, p.lineComment, token.NoPos}
p.imports = append(p.imports, spec)
return spec
@@ -2018,7 +2014,7 @@ func (p *parser) parseReceiver(scope *ast.Scope) *ast.FieldList {
// must have exactly one receiver
if par.NumFields() != 1 {
p.errorExpected(par.Opening, "exactly one receiver")
- par.List = []*ast.Field{&ast.Field{Type: &ast.BadExpr{par.Opening, par.Closing + 1}}}
+ par.List = []*ast.Field{{Type: &ast.BadExpr{par.Opening, par.Closing + 1}}}
return par
}
@@ -2027,7 +2023,7 @@ func (p *parser) parseReceiver(scope *ast.Scope) *ast.FieldList {
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()}}}
+ par.List = []*ast.Field{{Type: &ast.BadExpr{recv.Pos(), recv.End()}}}
}
return par
@@ -2103,18 +2099,6 @@ func (p *parser) parseDecl() ast.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
generated by cgit v1.2.3 (git 2.46.0) at 2025-10-16 00:14:37 +0000