diff options
Diffstat (limited to 'src/pkg/go/parser/interface.go')
| -rw-r--r-- | src/pkg/go/parser/interface.go | 29 |
1 files changed, 20 insertions, 9 deletions
diff --git a/src/pkg/go/parser/interface.go b/src/pkg/go/parser/interface.go index 39affdd6b..149257ca6 100644 --- a/src/pkg/go/parser/interface.go +++ b/src/pkg/go/parser/interface.go @@ -162,16 +162,27 @@ func ParseDir(fset *token.FileSet, path string, filter func(os.FileInfo) bool, m } // ParseExpr is a convenience function for obtaining the AST of an expression x. -// The position information recorded in the AST is undefined. +// The position information recorded in the AST is undefined. The filename used +// in error messages is the empty string. // func ParseExpr(x string) (ast.Expr, error) { - // parse x within the context of a complete package for correct scopes; - // use //line directive for correct positions in error messages and put - // x alone on a separate line (handles line comments), followed by a ';' - // to force an error if the expression is incomplete - file, err := ParseFile(token.NewFileSet(), "", "package p;func _(){_=\n//line :1\n"+x+"\n;}", 0) - if err != nil { - return nil, err + var p parser + p.init(token.NewFileSet(), "", []byte(x), 0) + + // Set up pkg-level scopes to avoid nil-pointer errors. + // This is not needed for a correct expression x as the + // parser will be ok with a nil topScope, but be cautious + // in case of an erroneous x. + p.openScope() + p.pkgScope = p.topScope + e := p.parseRhsOrType() + p.closeScope() + assert(p.topScope == nil, "unbalanced scopes") + + if p.errors.Len() > 0 { + p.errors.Sort() + return nil, p.errors.Err() } - return file.Decls[0].(*ast.FuncDecl).Body.List[0].(*ast.AssignStmt).Rhs[0], nil + + return e, nil } |