mirror of
https://github.com/golang/go
synced 2024-11-22 00:24:41 -07:00
Scoping snapshot.
- separate parsing from declaration - setup of correct scopes R=rsc CC=golang-dev https://golang.org/cl/189098
This commit is contained in:
Robert Griesemer
parent
69e244a104
commit
fcf4517423
@ -7,8 +7,8 @@ include ../../../Make.$(GOARCH)
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TARG=go/ast
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GOFILES=\
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ast.go\
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scope.go\
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filter.go\
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scope.go\
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walk.go\
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include ../../../Make.pkg
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@ -63,7 +63,7 @@ type parser struct {
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// Scopes
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pkgScope *ast.Scope
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fileScope *ast.Scope
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topScope *ast.Scope
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funcScope *ast.Scope
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}
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@ -82,6 +82,8 @@ func (p *parser) init(filename string, src []byte, mode uint) {
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p.mode = mode
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p.trace = mode&Trace != 0 // for convenience (p.trace is used frequently)
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p.check = mode&CheckSemantics != 0 // for convenience (p.check is used frequently)
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p.pkgScope = ast.NewScope(nil) // TODO(gri) should probably provide the pkgScope from outside
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p.fileScope = ast.NewScope(p.pkgScope)
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p.next()
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}
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@ -273,18 +275,17 @@ func (p *parser) expectSemi() {
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// ----------------------------------------------------------------------------
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// Scope support
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// Usage pattern: defer closeScope(openScope(p));
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func openScope(p *parser) *parser {
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p.topScope = ast.NewScope(p.topScope)
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return p
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func (p *parser) openScope() *ast.Scope {
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p.funcScope = ast.NewScope(p.funcScope)
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return p.funcScope
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}
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func closeScope(p *parser) { p.topScope = p.topScope.Outer }
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func (p *parser) closeScope() { p.funcScope = p.funcScope.Outer }
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func (p *parser) parseIdent(kind ast.ObjKind) *ast.Ident {
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obj := ast.NewObj(ast.Err, p.pos, "")
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obj := ast.NewObj(kind, p.pos, "_")
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if p.tok == token.IDENT {
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obj.Name = string(p.lit)
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p.next()
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@ -295,42 +296,16 @@ func (p *parser) parseIdent(kind ast.ObjKind) *ast.Ident {
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}
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// TODO(gri) Separate parsing from declaration since an identifier's
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// scope often starts only after the type has been seen.
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func (p *parser) declIdent(kind ast.ObjKind) *ast.Ident {
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obj := ast.NewObj(kind, p.pos, "")
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if p.tok == token.IDENT {
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obj.Name = string(p.lit)
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// TODO(gri) Consider reversing the conditionals below:
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// always do the declaration but only report
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// error if enabled (may be necessary to get
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// search functionality in the presence of
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// incorrect files).
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if p.check && !p.topScope.Declare(obj) {
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// TODO(gri) Declare could return already-declared
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// object for a very good error message.
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p.Error(obj.Pos, "'"+obj.Name+"' declared already")
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}
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p.next()
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} else {
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p.expect(token.IDENT) // use expect() error handling
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}
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return &ast.Ident{obj.Pos, obj}
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}
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// TODO(gri) Separate parsing from declaration since an identifier's
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// scope often starts only after the type has been seen.
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func (p *parser) declIdentList(kind ast.ObjKind) []*ast.Ident {
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func (p *parser) parseIdentList(kind ast.ObjKind) []*ast.Ident {
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if p.trace {
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defer un(trace(p, "IdentList"))
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}
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var list vector.Vector
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list.Push(p.declIdent(kind))
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list.Push(p.parseIdent(kind))
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for p.tok == token.COMMA {
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p.next()
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list.Push(p.declIdent(kind))
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list.Push(p.parseIdent(kind))
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}
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// convert vector
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@ -343,18 +318,43 @@ func (p *parser) declIdentList(kind ast.ObjKind) []*ast.Ident {
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}
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func (p *parser) declIdent(scope *ast.Scope, id *ast.Ident) {
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ok := scope.Declare(id.Obj)
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if p.check && !ok {
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p.Error(id.Pos(), "'"+id.Name()+"' declared already")
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}
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}
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func (p *parser) declIdentList(scope *ast.Scope, list []*ast.Ident) {
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for _, id := range list {
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p.declIdent(scope, id)
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}
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}
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func (p *parser) declFieldList(scope *ast.Scope, list []*ast.Field) {
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for _, f := range list {
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p.declIdentList(scope, f.Names)
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}
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}
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func (p *parser) findIdent() *ast.Ident {
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pos := p.pos
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name := ""
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var obj *ast.Object
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if p.tok == token.IDENT {
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name = string(p.lit)
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obj = p.topScope.Lookup(name)
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obj = p.funcScope.Lookup(name)
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p.next()
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} else {
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p.expect(token.IDENT) // use expect() error handling
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}
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if obj == nil {
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// TODO(gri) These identifiers need to be tracked as
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// unresolved identifiers in the package
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// scope so that they can be resolved later.
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obj = ast.NewObj(ast.Err, pos, name)
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}
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return &ast.Ident{pos, obj}
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@ -539,6 +539,9 @@ func (p *parser) parseStructType() *ast.StructType {
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fields[i] = x.(*ast.Field)
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}
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// TODO(gri) The struct scope shouldn't get lost.
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p.declFieldList(ast.NewScope(nil), fields)
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return &ast.StructType{pos, lbrace, fields, rbrace, false}
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}
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@ -619,7 +622,7 @@ func (p *parser) parseParameterList(ellipsisOk bool) []*ast.Field {
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}
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for p.tok != token.RPAREN && p.tok != token.EOF {
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idents := p.declIdentList(ast.Var)
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idents := p.parseIdentList(ast.Var)
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typ := p.parseParameterType(ellipsisOk)
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list.Push(&ast.Field{nil, idents, typ, nil, nil})
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if p.tok != token.COMMA {
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@ -646,32 +649,31 @@ func (p *parser) parseParameterList(ellipsisOk bool) []*ast.Field {
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}
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func (p *parser) parseParameters(ellipsisOk bool) []*ast.Field {
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func (p *parser) parseParameters(scope *ast.Scope, ellipsisOk bool) []*ast.Field {
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if p.trace {
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defer un(trace(p, "Parameters"))
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}
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var params []*ast.Field
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p.expect(token.LPAREN)
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openScope(p)
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if p.tok != token.RPAREN {
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params = p.parseParameterList(ellipsisOk)
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p.declFieldList(scope, params)
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}
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closeScope(p)
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p.expect(token.RPAREN)
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return params
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}
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func (p *parser) parseResult() []*ast.Field {
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func (p *parser) parseResult(scope *ast.Scope) []*ast.Field {
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if p.trace {
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defer un(trace(p, "Result"))
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}
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var results []*ast.Field
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if p.tok == token.LPAREN {
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results = p.parseParameters(false)
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results = p.parseParameters(scope, false)
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} else if p.tok != token.FUNC {
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typ := p.tryType()
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if typ != nil {
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@ -684,27 +686,28 @@ func (p *parser) parseResult() []*ast.Field {
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}
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func (p *parser) parseSignature() (params []*ast.Field, results []*ast.Field) {
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func (p *parser) parseSignature(scope *ast.Scope) (params []*ast.Field, results []*ast.Field) {
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if p.trace {
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defer un(trace(p, "Signature"))
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}
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params = p.parseParameters(true)
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results = p.parseResult()
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params = p.parseParameters(scope, true)
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results = p.parseResult(scope)
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return
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}
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func (p *parser) parseFuncType() *ast.FuncType {
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func (p *parser) parseFuncType() (*ast.Scope, *ast.FuncType) {
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if p.trace {
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defer un(trace(p, "FuncType"))
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}
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pos := p.expect(token.FUNC)
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params, results := p.parseSignature()
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scope := ast.NewScope(p.funcScope)
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params, results := p.parseSignature(scope)
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return &ast.FuncType{pos, params, results}
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return scope, &ast.FuncType{pos, params, results}
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}
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@ -720,7 +723,7 @@ func (p *parser) parseMethodSpec() *ast.Field {
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if ident, isIdent := x.(*ast.Ident); isIdent && p.tok == token.LPAREN {
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// method
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idents = []*ast.Ident{ident}
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params, results := p.parseSignature()
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params, results := p.parseSignature(ast.NewScope(p.funcScope))
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typ = &ast.FuncType{noPos, params, results}
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} else {
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// embedded interface
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@ -751,6 +754,9 @@ func (p *parser) parseInterfaceType() *ast.InterfaceType {
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methods[i] = x.(*ast.Field)
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}
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// TODO(gri) The interface scope shouldn't get lost.
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p.declFieldList(ast.NewScope(nil), methods)
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return &ast.InterfaceType{pos, lbrace, methods, rbrace, false}
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}
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@ -805,7 +811,8 @@ func (p *parser) tryRawType(ellipsisOk bool) ast.Expr {
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case token.MUL:
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return p.parsePointerType()
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case token.FUNC:
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return p.parseFuncType()
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_, typ := p.parseFuncType()
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return typ
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case token.INTERFACE:
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return p.parseInterfaceType()
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case token.MAP:
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@ -854,12 +861,31 @@ func (p *parser) parseStmtList() []ast.Stmt {
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}
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func (p *parser) parseBody(scope *ast.Scope) *ast.BlockStmt {
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if p.trace {
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defer un(trace(p, "Body"))
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}
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savedScope := p.funcScope
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p.funcScope = scope
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lbrace := p.expect(token.LBRACE)
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list := p.parseStmtList()
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rbrace := p.expect(token.RBRACE)
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p.funcScope = savedScope
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return &ast.BlockStmt{lbrace, list, rbrace}
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}
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func (p *parser) parseBlockStmt() *ast.BlockStmt {
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if p.trace {
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defer un(trace(p, "BlockStmt"))
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}
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defer closeScope(openScope(p))
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p.openScope()
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defer p.closeScope()
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lbrace := p.expect(token.LBRACE)
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list := p.parseStmtList()
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@ -877,14 +903,14 @@ func (p *parser) parseFuncTypeOrLit() ast.Expr {
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defer un(trace(p, "FuncTypeOrLit"))
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}
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typ := p.parseFuncType()
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scope, typ := p.parseFuncType()
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if p.tok != token.LBRACE {
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// function type only
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return typ
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}
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p.exprLev++
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body := p.parseBlockStmt()
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body := p.parseBody(scope)
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p.exprLev--
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return &ast.FuncLit{typ, body}
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@ -1418,7 +1444,8 @@ func (p *parser) parseIfStmt() *ast.IfStmt {
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}
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// IfStmt block
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defer closeScope(openScope(p))
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p.openScope()
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defer p.closeScope()
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pos := p.expect(token.IF)
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s1, s2, _ := p.parseControlClause(false)
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@ -1441,7 +1468,8 @@ func (p *parser) parseCaseClause() *ast.CaseClause {
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}
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// CaseClause block
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defer closeScope(openScope(p))
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p.openScope()
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defer p.closeScope()
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// SwitchCase
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pos := p.pos
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@ -1482,7 +1510,8 @@ func (p *parser) parseTypeCaseClause() *ast.TypeCaseClause {
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}
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// TypeCaseClause block
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defer closeScope(openScope(p))
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p.openScope()
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defer p.closeScope()
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// TypeSwitchCase
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pos := p.pos
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@ -1521,7 +1550,8 @@ func (p *parser) parseSwitchStmt() ast.Stmt {
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}
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// SwitchStmt block
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defer closeScope(openScope(p))
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p.openScope()
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defer p.closeScope()
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pos := p.expect(token.SWITCH)
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s1, s2, _ := p.parseControlClause(false)
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@ -1558,7 +1588,8 @@ func (p *parser) parseCommClause() *ast.CommClause {
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}
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// CommClause block
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defer closeScope(openScope(p))
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p.openScope()
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defer p.closeScope()
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// CommCase
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pos := p.pos
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@ -1621,7 +1652,8 @@ func (p *parser) parseForStmt() ast.Stmt {
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}
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// ForStmt block
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defer closeScope(openScope(p))
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p.openScope()
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defer p.closeScope()
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pos := p.expect(token.FOR)
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s1, s2, s3 := p.parseControlClause(true)
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@ -1740,7 +1772,8 @@ func parseImportSpec(p *parser, doc *ast.CommentGroup) ast.Spec {
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ident = &ast.Ident{p.pos, ast.NewObj(ast.Pkg, p.pos, ".")}
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p.next()
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} else if p.tok == token.IDENT {
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ident = p.declIdent(ast.Pkg)
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ident = p.parseIdent(ast.Pkg)
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p.declIdent(p.fileScope, ident)
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}
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var path []*ast.BasicLit
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@ -1762,13 +1795,23 @@ func parseConstSpec(p *parser, doc *ast.CommentGroup) ast.Spec {
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defer un(trace(p, "ConstSpec"))
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}
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idents := p.declIdentList(ast.Con)
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idents := p.parseIdentList(ast.Con)
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if p.funcScope == nil {
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// the scope of a constant outside any function
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// is the package scope
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p.declIdentList(p.pkgScope, idents)
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}
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typ := p.tryType()
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var values []ast.Expr
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if typ != nil || p.tok == token.ASSIGN {
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p.expect(token.ASSIGN)
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values = p.parseExprList()
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}
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if p.funcScope != nil {
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// the scope of a constant inside a function
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// begins after the the ConstSpec
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p.declIdentList(p.funcScope, idents)
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}
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p.expectSemi()
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return &ast.ValueSpec{doc, idents, typ, values, p.lineComment}
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@ -1780,7 +1823,15 @@ func parseTypeSpec(p *parser, doc *ast.CommentGroup) ast.Spec {
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defer un(trace(p, "TypeSpec"))
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}
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ident := p.declIdent(ast.Typ)
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ident := p.parseIdent(ast.Typ)
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// the scope of a type outside any function is
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// the package scope; the scope of a type inside
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// a function starts at the type identifier
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scope := p.funcScope
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if scope == nil {
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scope = p.pkgScope
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}
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p.declIdent(scope, ident)
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typ := p.parseType()
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p.expectSemi()
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@ -1793,13 +1844,23 @@ func parseVarSpec(p *parser, doc *ast.CommentGroup) ast.Spec {
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defer un(trace(p, "VarSpec"))
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}
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idents := p.declIdentList(ast.Var)
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idents := p.parseIdentList(ast.Var)
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if p.funcScope == nil {
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// the scope of a variable outside any function
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// is the pkgScope
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p.declIdentList(p.pkgScope, idents)
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}
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typ := p.tryType()
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var values []ast.Expr
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if typ == nil || p.tok == token.ASSIGN {
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p.expect(token.ASSIGN)
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values = p.parseExprList()
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}
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if p.funcScope != nil {
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// the scope of a variable inside a function
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// begins after the the VarSpec
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p.declIdentList(p.funcScope, idents)
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}
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p.expectSemi()
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return &ast.ValueSpec{doc, idents, typ, values, p.lineComment}
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@ -1837,13 +1898,13 @@ func (p *parser) parseGenDecl(keyword token.Token, f parseSpecFunction) *ast.Gen
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}
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func (p *parser) parseReceiver() *ast.Field {
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func (p *parser) parseReceiver(scope *ast.Scope) *ast.Field {
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if p.trace {
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defer un(trace(p, "Receiver"))
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}
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pos := p.pos
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par := p.parseParameters(false)
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par := p.parseParameters(scope, false)
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// must have exactly one receiver
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if len(par) != 1 || len(par) == 1 && len(par[0].Names) > 1 {
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@ -1873,18 +1934,20 @@ func (p *parser) parseFunctionDecl() *ast.FuncDecl {
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doc := p.leadComment
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pos := p.expect(token.FUNC)
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scope := ast.NewScope(p.funcScope)
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var recv *ast.Field
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if p.tok == token.LPAREN {
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recv = p.parseReceiver()
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recv = p.parseReceiver(scope)
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}
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ident := p.declIdent(ast.Fun)
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params, results := p.parseSignature()
|
||||
ident := p.parseIdent(ast.Fun)
|
||||
p.declIdent(p.pkgScope, ident) // there are no local function declarations
|
||||
params, results := p.parseSignature(scope)
|
||||
|
||||
var body *ast.BlockStmt
|
||||
if p.tok == token.LBRACE {
|
||||
body = p.parseBlockStmt()
|
||||
body = p.parseBody(scope)
|
||||
}
|
||||
p.expectSemi()
|
||||
|
||||
@ -1957,9 +2020,6 @@ func (p *parser) parseFile() *ast.File {
|
||||
ident := p.parseIdent(ast.Pkg) // package name is in no scope
|
||||
p.expectSemi()
|
||||
|
||||
// file block
|
||||
defer closeScope(openScope(p))
|
||||
|
||||
var decls []ast.Decl
|
||||
|
||||
// Don't bother parsing the rest if we had errors already.
|
||||
|
||||
Loading…
Reference in New Issue
Block a user