diff options
Diffstat (limited to 'libgo/go/go/parser/parser.go')
| -rw-r--r-- | libgo/go/go/parser/parser.go | 454 |
1 files changed, 321 insertions, 133 deletions
diff --git a/libgo/go/go/parser/parser.go b/libgo/go/go/parser/parser.go index 6bee8de9f65..e362e13a7b6 100644 --- a/libgo/go/go/parser/parser.go +++ b/libgo/go/go/parser/parser.go @@ -14,12 +14,15 @@ import ( "go/ast" "go/scanner" "go/token" + "strconv" + "strings" + "unicode" ) // The parser structure holds the parser's internal state. type parser struct { - file *token.File - scanner.ErrorVector + file *token.File + errors scanner.ErrorList scanner scanner.Scanner // Tracing/debugging @@ -37,6 +40,13 @@ type parser struct { tok token.Token // one token look-ahead lit string // token literal + // Error recovery + // (used to limit the number of calls to syncXXX functions + // w/o making scanning progress - avoids potential endless + // loops across multiple parser functions during error recovery) + syncPos token.Pos // last synchronization position + syncCnt int // number of calls to syncXXX without progress + // Non-syntactic parser control exprLev int // < 0: in control clause, >= 0: in expression @@ -58,7 +68,8 @@ func (p *parser) init(fset *token.FileSet, filename string, src []byte, mode Mod if mode&ParseComments != 0 { m = scanner.ScanComments } - p.scanner.Init(p.file, src, p, m) + eh := func(pos token.Position, msg string) { p.errors.Add(pos, msg) } + p.scanner.Init(p.file, src, eh, m) p.mode = mode p.trace = mode&Trace != 0 // for convenience (p.trace is used frequently) @@ -74,14 +85,6 @@ func (p *parser) init(fset *token.FileSet, filename string, src []byte, mode Mod p.openLabelScope() } -func (p *parser) errors() error { - m := scanner.Sorted - if p.mode&SpuriousErrors == 0 { - m = scanner.NoMultiples - } - return p.GetError(m) -} - // ---------------------------------------------------------------------------- // Scoping support @@ -256,7 +259,7 @@ func (p *parser) consumeComment() (comment *ast.Comment, endline int) { } } - comment = &ast.Comment{p.pos, p.lit} + comment = &ast.Comment{Slash: p.pos, Text: p.lit} p.next0() return @@ -277,7 +280,7 @@ func (p *parser) consumeCommentGroup() (comments *ast.CommentGroup, endline int) } // add comment group to the comments list - comments = &ast.CommentGroup{list} + comments = &ast.CommentGroup{List: list} p.comments = append(p.comments, comments) return @@ -334,7 +337,7 @@ func (p *parser) next() { } func (p *parser) error(pos token.Pos, msg string) { - p.Error(p.file.Position(pos), msg) + p.errors.Add(p.file.Position(pos), msg) } func (p *parser) errorExpected(pos token.Pos, msg string) { @@ -342,7 +345,7 @@ func (p *parser) errorExpected(pos token.Pos, msg string) { 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' { + if p.tok == token.SEMICOLON && p.lit == "\n" { msg += ", found newline" } else { msg += ", found '" + p.tok.String() + "'" @@ -363,18 +366,109 @@ func (p *parser) expect(tok token.Token) token.Pos { return pos } +// expectClosing is like expect but provides a better error message +// for the common case of a missing comma before a newline. +// +func (p *parser) expectClosing(tok token.Token, context string) token.Pos { + if p.tok != tok && p.tok == token.SEMICOLON && p.lit == "\n" { + p.error(p.pos, "missing ',' before newline in "+context) + p.next() + } + return p.expect(tok) +} + func (p *parser) expectSemi() { + // semicolon is optional before a closing ')' or '}' if p.tok != token.RPAREN && p.tok != token.RBRACE { - p.expect(token.SEMICOLON) + if p.tok == token.SEMICOLON { + p.next() + } else { + p.errorExpected(p.pos, "';'") + syncStmt(p) + } } } +func (p *parser) atComma(context string) bool { + if p.tok == token.COMMA { + return true + } + if p.tok == token.SEMICOLON && p.lit == "\n" { + p.error(p.pos, "missing ',' before newline in "+context) + return true // "insert" the comma and continue + + } + return false +} + func assert(cond bool, msg string) { if !cond { panic("go/parser internal error: " + msg) } } +// syncStmt advances to the next statement. +// Used for synchronization after an error. +// +func syncStmt(p *parser) { + for { + switch p.tok { + case token.BREAK, token.CONST, token.CONTINUE, token.DEFER, + token.FALLTHROUGH, token.FOR, token.GO, token.GOTO, + token.IF, token.RETURN, token.SELECT, token.SWITCH, + token.TYPE, token.VAR: + // Return only if parser made some progress since last + // sync or if it has not reached 10 sync calls without + // progress. Otherwise consume at least one token to + // avoid an endless parser loop (it is possible that + // both parseOperand and parseStmt call syncStmt and + // correctly do not advance, thus the need for the + // invocation limit p.syncCnt). + if p.pos == p.syncPos && p.syncCnt < 10 { + p.syncCnt++ + return + } + if p.pos > p.syncPos { + p.syncPos = p.pos + p.syncCnt = 0 + return + } + // Reaching here indicates a parser bug, likely an + // incorrect token list in this function, but it only + // leads to skipping of possibly correct code if a + // previous error is present, and thus is preferred + // over a non-terminating parse. + case token.EOF: + return + } + p.next() + } +} + +// syncDecl advances to the next declaration. +// Used for synchronization after an error. +// +func syncDecl(p *parser) { + for { + switch p.tok { + case token.CONST, token.TYPE, token.VAR: + // see comments in syncStmt + if p.pos == p.syncPos && p.syncCnt < 10 { + p.syncCnt++ + return + } + if p.pos > p.syncPos { + p.syncPos = p.pos + p.syncCnt = 0 + return + } + case token.EOF: + return + } + p.next() + } +} + // ---------------------------------------------------------------------------- // Identifiers @@ -387,7 +481,7 @@ func (p *parser) parseIdent() *ast.Ident { } else { p.expect(token.IDENT) // use expect() error handling } - return &ast.Ident{pos, name, nil} + return &ast.Ident{NamePos: pos, Name: name} } func (p *parser) parseIdentList() (list []*ast.Ident) { @@ -465,7 +559,7 @@ func (p *parser) parseType() ast.Expr { pos := p.pos p.errorExpected(pos, "type") p.next() // make progress - return &ast.BadExpr{pos, p.pos} + return &ast.BadExpr{From: pos, To: p.pos} } return typ @@ -485,7 +579,7 @@ func (p *parser) parseTypeName() ast.Expr { p.next() p.resolve(ident) sel := p.parseIdent() - return &ast.SelectorExpr{ident, sel} + return &ast.SelectorExpr{X: ident, Sel: sel} } return ident @@ -499,7 +593,7 @@ func (p *parser) parseArrayType(ellipsisOk bool) ast.Expr { lbrack := p.expect(token.LBRACK) var len ast.Expr if ellipsisOk && p.tok == token.ELLIPSIS { - len = &ast.Ellipsis{p.pos, nil} + len = &ast.Ellipsis{Ellipsis: p.pos} p.next() } else if p.tok != token.RBRACK { len = p.parseRhs() @@ -507,7 +601,7 @@ func (p *parser) parseArrayType(ellipsisOk bool) ast.Expr { p.expect(token.RBRACK) elt := p.parseType() - return &ast.ArrayType{lbrack, len, elt} + return &ast.ArrayType{Lbrack: lbrack, Len: len, Elt: elt} } func (p *parser) makeIdentList(list []ast.Expr) []*ast.Ident { @@ -515,9 +609,11 @@ func (p *parser) makeIdentList(list []ast.Expr) []*ast.Ident { for i, x := range list { ident, isIdent := x.(*ast.Ident) if !isIdent { - pos := x.Pos() - p.errorExpected(pos, "identifier") - ident = &ast.Ident{pos, "_", nil} + if _, isBad := x.(*ast.BadExpr); !isBad { + // only report error if it's a new one + p.errorExpected(x.Pos(), "identifier") + } + ident = &ast.Ident{NamePos: x.Pos(), Name: "_"} } idents[i] = ident } @@ -537,7 +633,7 @@ func (p *parser) parseFieldDecl(scope *ast.Scope) *ast.Field { // optional tag var tag *ast.BasicLit if p.tok == token.STRING { - tag = &ast.BasicLit{p.pos, p.tok, p.lit} + tag = &ast.BasicLit{ValuePos: p.pos, Kind: p.tok, Value: p.lit} p.next() } @@ -553,13 +649,13 @@ func (p *parser) parseFieldDecl(scope *ast.Scope) *ast.Field { 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()} + typ = &ast.BadExpr{From: pos, To: list[n-1].End()} } } p.expectSemi() // call before accessing p.linecomment - field := &ast.Field{doc, idents, typ, tag, p.lineComment} + field := &ast.Field{Doc: doc, Names: idents, Type: typ, Tag: tag, Comment: p.lineComment} p.declare(field, nil, scope, ast.Var, idents...) return field @@ -582,7 +678,14 @@ func (p *parser) parseStructType() *ast.StructType { } rbrace := p.expect(token.RBRACE) - return &ast.StructType{pos, &ast.FieldList{lbrace, list, rbrace}, false} + return &ast.StructType{ + Struct: pos, + Fields: &ast.FieldList{ + Opening: lbrace, + List: list, + Closing: rbrace, + }, + } } func (p *parser) parsePointerType() *ast.StarExpr { @@ -593,7 +696,7 @@ func (p *parser) parsePointerType() *ast.StarExpr { star := p.expect(token.MUL) base := p.parseType() - return &ast.StarExpr{star, base} + return &ast.StarExpr{Star: star, X: base} } func (p *parser) tryVarType(isParam bool) ast.Expr { @@ -603,9 +706,9 @@ func (p *parser) tryVarType(isParam bool) ast.Expr { 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} + typ = &ast.BadExpr{From: pos, To: p.pos} } - return &ast.Ellipsis{pos, typ} + return &ast.Ellipsis{Ellipsis: pos, Elt: typ} } return p.tryIdentOrType(false) } @@ -616,7 +719,7 @@ func (p *parser) parseVarType(isParam bool) ast.Expr { pos := p.pos p.errorExpected(pos, "type") p.next() // make progress - typ = &ast.BadExpr{pos, p.pos} + typ = &ast.BadExpr{From: pos, To: p.pos} } return typ } @@ -657,7 +760,7 @@ func (p *parser) parseParameterList(scope *ast.Scope, ellipsisOk bool) (params [ if typ != nil { // IdentifierList Type idents := p.makeIdentList(list) - field := &ast.Field{nil, idents, typ, nil, nil} + field := &ast.Field{Names: idents, Type: typ} params = append(params, field) // Go spec: The scope of an identifier denoting a function // parameter or result variable is the function body. @@ -669,12 +772,12 @@ func (p *parser) parseParameterList(scope *ast.Scope, ellipsisOk bool) (params [ for p.tok != token.RPAREN && p.tok != token.EOF { idents := p.parseIdentList() typ := p.parseVarType(ellipsisOk) - field := &ast.Field{nil, idents, typ, nil, nil} + field := &ast.Field{Names: idents, Type: typ} 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, nil, scope, ast.Var, idents...) - if p.tok != token.COMMA { + if !p.atComma("parameter list") { break } p.next() @@ -704,7 +807,7 @@ func (p *parser) parseParameters(scope *ast.Scope, ellipsisOk bool) *ast.FieldLi } rparen := p.expect(token.RPAREN) - return &ast.FieldList{lparen, params, rparen} + return &ast.FieldList{Opening: lparen, List: params, Closing: rparen} } func (p *parser) parseResult(scope *ast.Scope) *ast.FieldList { @@ -746,7 +849,7 @@ func (p *parser) parseFuncType() (*ast.FuncType, *ast.Scope) { scope := ast.NewScope(p.topScope) // function scope params, results := p.parseSignature(scope) - return &ast.FuncType{pos, params, results}, scope + return &ast.FuncType{Func: pos, Params: params, Results: results}, scope } func (p *parser) parseMethodSpec(scope *ast.Scope) *ast.Field { @@ -763,7 +866,7 @@ func (p *parser) parseMethodSpec(scope *ast.Scope) *ast.Field { idents = []*ast.Ident{ident} scope := ast.NewScope(nil) // method scope params, results := p.parseSignature(scope) - typ = &ast.FuncType{token.NoPos, params, results} + typ = &ast.FuncType{Func: token.NoPos, Params: params, Results: results} } else { // embedded interface typ = x @@ -771,7 +874,7 @@ func (p *parser) parseMethodSpec(scope *ast.Scope) *ast.Field { } p.expectSemi() // call before accessing p.linecomment - spec := &ast.Field{doc, idents, typ, nil, p.lineComment} + spec := &ast.Field{Doc: doc, Names: idents, Type: typ, Comment: p.lineComment} p.declare(spec, nil, scope, ast.Fun, idents...) return spec @@ -791,7 +894,14 @@ func (p *parser) parseInterfaceType() *ast.InterfaceType { } rbrace := p.expect(token.RBRACE) - return &ast.InterfaceType{pos, &ast.FieldList{lbrace, list, rbrace}, false} + return &ast.InterfaceType{ + Interface: pos, + Methods: &ast.FieldList{ + Opening: lbrace, + List: list, + Closing: rbrace, + }, + } } func (p *parser) parseMapType() *ast.MapType { @@ -805,7 +915,7 @@ func (p *parser) parseMapType() *ast.MapType { p.expect(token.RBRACK) value := p.parseType() - return &ast.MapType{pos, key, value} + return &ast.MapType{Map: pos, Key: key, Value: value} } func (p *parser) parseChanType() *ast.ChanType { @@ -828,7 +938,7 @@ func (p *parser) parseChanType() *ast.ChanType { } value := p.parseType() - return &ast.ChanType{pos, dir, value} + return &ast.ChanType{Begin: pos, Dir: dir, Value: value} } // If the result is an identifier, it is not resolved. @@ -856,7 +966,7 @@ func (p *parser) tryIdentOrType(ellipsisOk bool) ast.Expr { p.next() typ := p.parseType() rparen := p.expect(token.RPAREN) - return &ast.ParenExpr{lparen, typ, rparen} + return &ast.ParenExpr{Lparen: lparen, X: typ, Rparen: rparen} } // no type found @@ -899,7 +1009,7 @@ func (p *parser) parseBody(scope *ast.Scope) *ast.BlockStmt { p.closeScope() rbrace := p.expect(token.RBRACE) - return &ast.BlockStmt{lbrace, list, rbrace} + return &ast.BlockStmt{Lbrace: lbrace, List: list, Rbrace: rbrace} } func (p *parser) parseBlockStmt() *ast.BlockStmt { @@ -913,7 +1023,7 @@ func (p *parser) parseBlockStmt() *ast.BlockStmt { p.closeScope() rbrace := p.expect(token.RBRACE) - return &ast.BlockStmt{lbrace, list, rbrace} + return &ast.BlockStmt{Lbrace: lbrace, List: list, Rbrace: rbrace} } // ---------------------------------------------------------------------------- @@ -934,7 +1044,7 @@ func (p *parser) parseFuncTypeOrLit() ast.Expr { body := p.parseBody(scope) p.exprLev-- - return &ast.FuncLit{typ, body} + return &ast.FuncLit{Type: typ, Body: body} } // parseOperand may return an expression or a raw type (incl. array @@ -955,7 +1065,7 @@ func (p *parser) parseOperand(lhs bool) ast.Expr { return x case token.INT, token.FLOAT, token.IMAG, token.CHAR, token.STRING: - x := &ast.BasicLit{p.pos, p.tok, p.lit} + x := &ast.BasicLit{ValuePos: p.pos, Kind: p.tok, Value: p.lit} p.next() return x @@ -966,24 +1076,24 @@ func (p *parser) parseOperand(lhs bool) ast.Expr { x := p.parseRhsOrType() // types may be parenthesized: (some type) p.exprLev-- rparen := p.expect(token.RPAREN) - return &ast.ParenExpr{lparen, x, rparen} + return &ast.ParenExpr{Lparen: lparen, X: x, Rparen: 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 - } + 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 } + // we have an error pos := p.pos p.errorExpected(pos, "operand") - p.next() // make progress - return &ast.BadExpr{pos, p.pos} + syncStmt(p) + return &ast.BadExpr{From: pos, To: p.pos} } func (p *parser) parseSelector(x ast.Expr) ast.Expr { @@ -993,7 +1103,7 @@ func (p *parser) parseSelector(x ast.Expr) ast.Expr { sel := p.parseIdent() - return &ast.SelectorExpr{x, sel} + return &ast.SelectorExpr{X: x, Sel: sel} } func (p *parser) parseTypeAssertion(x ast.Expr) ast.Expr { @@ -1011,7 +1121,7 @@ func (p *parser) parseTypeAssertion(x ast.Expr) ast.Expr { } p.expect(token.RPAREN) - return &ast.TypeAssertExpr{x, typ} + return &ast.TypeAssertExpr{X: x, Type: typ} } func (p *parser) parseIndexOrSlice(x ast.Expr) ast.Expr { @@ -1037,9 +1147,9 @@ func (p *parser) parseIndexOrSlice(x ast.Expr) ast.Expr { rbrack := p.expect(token.RBRACK) if isSlice { - return &ast.SliceExpr{x, lbrack, low, high, rbrack} + return &ast.SliceExpr{X: x, Lbrack: lbrack, Low: low, High: high, Rbrack: rbrack} } - return &ast.IndexExpr{x, lbrack, low, rbrack} + return &ast.IndexExpr{X: x, Lbrack: lbrack, Index: low, Rbrack: rbrack} } func (p *parser) parseCallOrConversion(fun ast.Expr) *ast.CallExpr { @@ -1057,15 +1167,15 @@ func (p *parser) parseCallOrConversion(fun ast.Expr) *ast.CallExpr { ellipsis = p.pos p.next() } - if p.tok != token.COMMA { + if !p.atComma("argument list") { break } p.next() } p.exprLev-- - rparen := p.expect(token.RPAREN) + rparen := p.expectClosing(token.RPAREN, "argument list") - return &ast.CallExpr{fun, lparen, list, ellipsis, rparen} + return &ast.CallExpr{Fun: fun, Lparen: lparen, Args: list, Ellipsis: ellipsis, Rparen: rparen} } func (p *parser) parseElement(keyOk bool) ast.Expr { @@ -1082,7 +1192,7 @@ func (p *parser) parseElement(keyOk bool) ast.Expr { if p.tok == token.COLON { colon := p.pos p.next() - return &ast.KeyValueExpr{x, colon, p.parseElement(false)} + return &ast.KeyValueExpr{Key: x, Colon: colon, Value: p.parseElement(false)} } p.resolve(x) // not a map key } @@ -1097,7 +1207,7 @@ func (p *parser) parseElementList() (list []ast.Expr) { for p.tok != token.RBRACE && p.tok != token.EOF { list = append(list, p.parseElement(true)) - if p.tok != token.COMMA { + if !p.atComma("composite literal") { break } p.next() @@ -1118,8 +1228,8 @@ func (p *parser) parseLiteralValue(typ ast.Expr) ast.Expr { elts = p.parseElementList() } p.exprLev-- - rbrace := p.expect(token.RBRACE) - return &ast.CompositeLit{typ, lbrace, elts, rbrace} + rbrace := p.expectClosing(token.RBRACE, "composite literal") + return &ast.CompositeLit{Type: typ, Lbrace: lbrace, Elts: elts, Rbrace: rbrace} } // checkExpr checks that x is an expression (and not a type). @@ -1148,7 +1258,7 @@ func (p *parser) checkExpr(x ast.Expr) ast.Expr { default: // all other nodes are not proper expressions p.errorExpected(x.Pos(), "expression") - x = &ast.BadExpr{x.Pos(), x.End()} + x = &ast.BadExpr{From: x.Pos(), To: x.End()} } return x } @@ -1211,7 +1321,7 @@ func (p *parser) checkExprOrType(x ast.Expr) ast.Expr { 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()} + x = &ast.BadExpr{From: x.Pos(), To: x.End()} } } @@ -1241,9 +1351,9 @@ L: 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} + p.next() // make progress + x = &ast.BadExpr{From: pos, To: p.pos} } case token.LBRACK: if lhs { @@ -1284,7 +1394,7 @@ func (p *parser) parseUnaryExpr(lhs bool) ast.Expr { pos, op := p.pos, p.tok p.next() x := p.parseUnaryExpr(false) - return &ast.UnaryExpr{pos, op, p.checkExpr(x)} + return &ast.UnaryExpr{OpPos: pos, Op: op, X: p.checkExpr(x)} case token.ARROW: // channel type or receive expression @@ -1293,18 +1403,18 @@ func (p *parser) parseUnaryExpr(lhs bool) ast.Expr { if p.tok == token.CHAN { p.next() value := p.parseType() - return &ast.ChanType{pos, ast.RECV, value} + return &ast.ChanType{Begin: pos, Dir: ast.RECV, Value: value} } x := p.parseUnaryExpr(false) - return &ast.UnaryExpr{pos, token.ARROW, p.checkExpr(x)} + return &ast.UnaryExpr{OpPos: pos, Op: token.ARROW, X: 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 &ast.StarExpr{Star: pos, X: p.checkExprOrType(x)} } return p.parsePrimaryExpr(lhs) @@ -1326,7 +1436,7 @@ func (p *parser) parseBinaryExpr(lhs bool, prec1 int) ast.Expr { lhs = false } y := p.parseBinaryExpr(false, prec+1) - x = &ast.BinaryExpr{p.checkExpr(x), pos, op, p.checkExpr(y)} + x = &ast.BinaryExpr{X: p.checkExpr(x), OpPos: pos, Op: op, Y: p.checkExpr(y)} } } @@ -1388,12 +1498,12 @@ func (p *parser) parseSimpleStmt(mode int) (ast.Stmt, bool) { if mode == rangeOk && p.tok == token.RANGE && (tok == token.DEFINE || tok == token.ASSIGN) { pos := p.pos p.next() - y = []ast.Expr{&ast.UnaryExpr{pos, token.RANGE, p.parseRhs()}} + y = []ast.Expr{&ast.UnaryExpr{OpPos: pos, Op: token.RANGE, X: p.parseRhs()}} isRange = true } else { y = p.parseRhsList() } - as := &ast.AssignStmt{x, pos, tok, y} + as := &ast.AssignStmt{Lhs: x, TokPos: pos, Tok: tok, Rhs: y} if tok == token.DEFINE { p.shortVarDecl(as, x) } @@ -1414,7 +1524,7 @@ func (p *parser) parseSimpleStmt(mode int) (ast.Stmt, bool) { // 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()} + stmt := &ast.LabeledStmt{Label: label, Colon: colon, Stmt: p.parseStmt()} p.declare(stmt, nil, p.labelScope, ast.Lbl, label) return stmt, false } @@ -1425,24 +1535,24 @@ func (p *parser) parseSimpleStmt(mode int) (ast.Stmt, bool) { // before the ':' that caused the problem. Thus, use the (latest) colon // position for error reporting. p.error(colon, "illegal label declaration") - return &ast.BadStmt{x[0].Pos(), colon + 1}, false + return &ast.BadStmt{From: x[0].Pos(), To: colon + 1}, false case token.ARROW: // send statement arrow := p.pos p.next() y := p.parseRhs() - return &ast.SendStmt{x[0], arrow, y}, false + return &ast.SendStmt{Chan: x[0], Arrow: arrow, Value: y}, false case token.INC, token.DEC: // increment or decrement - s := &ast.IncDecStmt{x[0], p.pos, p.tok} + s := &ast.IncDecStmt{X: x[0], TokPos: p.pos, Tok: p.tok} p.next() return s, false } // expression - return &ast.ExprStmt{x[0]}, false + return &ast.ExprStmt{X: x[0]}, false } func (p *parser) parseCallExpr() *ast.CallExpr { @@ -1450,7 +1560,10 @@ func (p *parser) parseCallExpr() *ast.CallExpr { if call, isCall := x.(*ast.CallExpr); isCall { return call } - p.errorExpected(x.Pos(), "function/method call") + if _, isBad := x.(*ast.BadExpr); !isBad { + // only report error if it's a new one + p.errorExpected(x.Pos(), "function/method call") + } return nil } @@ -1463,10 +1576,10 @@ func (p *parser) parseGoStmt() ast.Stmt { call := p.parseCallExpr() p.expectSemi() if call == nil { - return &ast.BadStmt{pos, pos + 2} // len("go") + return &ast.BadStmt{From: pos, To: pos + 2} // len("go") } - return &ast.GoStmt{pos, call} + return &ast.GoStmt{Go: pos, Call: call} } func (p *parser) parseDeferStmt() ast.Stmt { @@ -1478,10 +1591,10 @@ func (p *parser) parseDeferStmt() ast.Stmt { call := p.parseCallExpr() p.expectSemi() if call == nil { - return &ast.BadStmt{pos, pos + 5} // len("defer") + return &ast.BadStmt{From: pos, To: pos + 5} // len("defer") } - return &ast.DeferStmt{pos, call} + return &ast.DeferStmt{Defer: pos, Call: call} } func (p *parser) parseReturnStmt() *ast.ReturnStmt { @@ -1497,7 +1610,7 @@ func (p *parser) parseReturnStmt() *ast.ReturnStmt { } p.expectSemi() - return &ast.ReturnStmt{pos, x} + return &ast.ReturnStmt{Return: pos, Results: x} } func (p *parser) parseBranchStmt(tok token.Token) *ast.BranchStmt { @@ -1515,7 +1628,7 @@ func (p *parser) parseBranchStmt(tok token.Token) *ast.BranchStmt { } p.expectSemi() - return &ast.BranchStmt{pos, tok, label} + return &ast.BranchStmt{TokPos: pos, Tok: tok, Label: label} } func (p *parser) makeExpr(s ast.Stmt) ast.Expr { @@ -1526,7 +1639,7 @@ func (p *parser) makeExpr(s ast.Stmt) ast.Expr { return p.checkExpr(es.X) } p.error(s.Pos(), "expected condition, found simple statement") - return &ast.BadExpr{s.Pos(), s.End()} + return &ast.BadExpr{From: s.Pos(), To: s.End()} } func (p *parser) parseIfStmt() *ast.IfStmt { @@ -1568,7 +1681,7 @@ func (p *parser) parseIfStmt() *ast.IfStmt { p.expectSemi() } - return &ast.IfStmt{pos, s, x, body, else_} + return &ast.IfStmt{If: pos, Init: s, Cond: x, Body: body, Else: else_} } func (p *parser) parseTypeList() (list []ast.Expr) { @@ -1608,7 +1721,7 @@ func (p *parser) parseCaseClause(typeSwitch bool) *ast.CaseClause { body := p.parseStmtList() p.closeScope() - return &ast.CaseClause{pos, list, colon, body} + return &ast.CaseClause{Case: pos, List: list, Colon: colon, Body: body} } func isTypeSwitchAssert(x ast.Expr) bool { @@ -1677,13 +1790,13 @@ func (p *parser) parseSwitchStmt() ast.Stmt { } rbrace := p.expect(token.RBRACE) p.expectSemi() - body := &ast.BlockStmt{lbrace, list, rbrace} + body := &ast.BlockStmt{Lbrace: lbrace, List: list, Rbrace: rbrace} if typeSwitch { - return &ast.TypeSwitchStmt{pos, s1, s2, body} + return &ast.TypeSwitchStmt{Switch: pos, Init: s1, Assign: s2, Body: body} } - return &ast.SwitchStmt{pos, s1, p.makeExpr(s2), body} + return &ast.SwitchStmt{Switch: pos, Init: s1, Tag: p.makeExpr(s2), Body: body} } func (p *parser) parseCommClause() *ast.CommClause { @@ -1706,7 +1819,7 @@ func (p *parser) parseCommClause() *ast.CommClause { arrow := p.pos p.next() rhs := p.parseRhs() - comm = &ast.SendStmt{lhs[0], arrow, rhs} + comm = &ast.SendStmt{Chan: lhs[0], Arrow: arrow, Value: rhs} } else { // RecvStmt if tok := p.tok; tok == token.ASSIGN || tok == token.DEFINE { @@ -1719,7 +1832,7 @@ func (p *parser) parseCommClause() *ast.CommClause { pos := p.pos p.next() rhs := p.parseRhs() - as := &ast.AssignStmt{lhs, pos, tok, []ast.Expr{rhs}} + as := &ast.AssignStmt{Lhs: lhs, TokPos: pos, Tok: tok, Rhs: []ast.Expr{rhs}} if tok == token.DEFINE { p.shortVarDecl(as, lhs) } @@ -1730,7 +1843,7 @@ func (p *parser) parseCommClause() *ast.CommClause { p.errorExpected(lhs[0].Pos(), "1 expression") // continue with first expression } - comm = &ast.ExprStmt{lhs[0]} + comm = &ast.ExprStmt{X: lhs[0]} } } } else { @@ -1741,7 +1854,7 @@ func (p *parser) parseCommClause() *ast.CommClause { body := p.parseStmtList() p.closeScope() - return &ast.CommClause{pos, comm, colon, body} + return &ast.CommClause{Case: pos, Comm: comm, Colon: colon, Body: body} } func (p *parser) parseSelectStmt() *ast.SelectStmt { @@ -1757,9 +1870,9 @@ func (p *parser) parseSelectStmt() *ast.SelectStmt { } rbrace := p.expect(token.RBRACE) p.expectSemi() - body := &ast.BlockStmt{lbrace, list, rbrace} + body := &ast.BlockStmt{Lbrace: lbrace, List: list, Rbrace: rbrace} - return &ast.SelectStmt{pos, body} + return &ast.SelectStmt{Select: pos, Body: body} } func (p *parser) parseForStmt() ast.Stmt { @@ -1808,16 +1921,30 @@ func (p *parser) parseForStmt() ast.Stmt { key = as.Lhs[0] default: p.errorExpected(as.Lhs[0].Pos(), "1 or 2 expressions") - return &ast.BadStmt{pos, body.End()} + return &ast.BadStmt{From: pos, To: body.End()} } // parseSimpleStmt returned a right-hand side that // is a single unary expression of the form "range x" x := as.Rhs[0].(*ast.UnaryExpr).X - return &ast.RangeStmt{pos, key, value, as.TokPos, as.Tok, x, body} + return &ast.RangeStmt{ + For: pos, + Key: key, + Value: value, + TokPos: as.TokPos, + Tok: as.Tok, + X: x, + Body: body, + } } // regular for statement - return &ast.ForStmt{pos, s1, p.makeExpr(s2), s3, body} + return &ast.ForStmt{ + For: pos, + Init: s1, + Cond: p.makeExpr(s2), + Post: s3, + Body: body, + } } func (p *parser) parseStmt() (s ast.Stmt) { @@ -1827,12 +1954,12 @@ func (p *parser) parseStmt() (s ast.Stmt) { switch p.tok { case token.CONST, token.TYPE, token.VAR: - s = &ast.DeclStmt{p.parseDecl()} + s = &ast.DeclStmt{Decl: p.parseDecl(syncStmt)} 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 + // tokens that may start an expression + token.IDENT, token.INT, token.FLOAT, token.IMAG, token.CHAR, token.STRING, token.FUNC, token.LPAREN, // operands + token.LBRACK, token.STRUCT, // composite types + token.ADD, token.SUB, token.MUL, token.AND, token.XOR, token.ARROW, token.NOT: // unary operators s, _ = p.parseSimpleStmt(labelOk) // because of the required look-ahead, labeled statements are // parsed by parseSimpleStmt - don't expect a semicolon after @@ -1860,17 +1987,17 @@ func (p *parser) parseStmt() (s ast.Stmt) { case token.FOR: s = p.parseForStmt() case token.SEMICOLON: - s = &ast.EmptyStmt{p.pos} + s = &ast.EmptyStmt{Semicolon: p.pos} p.next() case token.RBRACE: // a semicolon may be omitted before a closing "}" - s = &ast.EmptyStmt{p.pos} + s = &ast.EmptyStmt{Semicolon: p.pos} default: // no statement found pos := p.pos p.errorExpected(pos, "statement") - p.next() // make progress - s = &ast.BadStmt{pos, p.pos} + syncStmt(p) + s = &ast.BadStmt{From: pos, To: p.pos} } return @@ -1881,6 +2008,17 @@ func (p *parser) parseStmt() (s ast.Stmt) { type parseSpecFunction func(p *parser, doc *ast.CommentGroup, iota int) ast.Spec +func isValidImport(lit string) bool { + const illegalChars = `!"#$%&'()*,:;<=>?[\]^{|}` + "`\uFFFD" + s, _ := strconv.Unquote(lit) // go/scanner returns a legal string literal + for _, r := range s { + if !unicode.IsGraphic(r) || unicode.IsSpace(r) || strings.ContainsRune(illegalChars, r) { + return false + } + } + return s != "" +} + func parseImportSpec(p *parser, doc *ast.CommentGroup, _ int) ast.Spec { if p.trace { defer un(trace(p, "ImportSpec")) @@ -1889,7 +2027,7 @@ func parseImportSpec(p *parser, doc *ast.CommentGroup, _ int) ast.Spec { var ident *ast.Ident switch p.tok { case token.PERIOD: - ident = &ast.Ident{p.pos, ".", nil} + ident = &ast.Ident{NamePos: p.pos, Name: "."} p.next() case token.IDENT: ident = p.parseIdent() @@ -1897,7 +2035,10 @@ func parseImportSpec(p *parser, doc *ast.CommentGroup, _ int) ast.Spec { var path *ast.BasicLit if p.tok == token.STRING { - path = &ast.BasicLit{p.pos, p.tok, p.lit} + if !isValidImport(p.lit) { + p.error(p.pos, "invalid import path: "+p.lit) + } + path = &ast.BasicLit{ValuePos: p.pos, Kind: p.tok, Value: p.lit} p.next() } else { p.expect(token.STRING) // use expect() error handling @@ -1905,7 +2046,12 @@ 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, token.NoPos} + spec := &ast.ImportSpec{ + Doc: doc, + Name: ident, + Path: path, + Comment: p.lineComment, + } p.imports = append(p.imports, spec) return spec @@ -1929,7 +2075,13 @@ func parseConstSpec(p *parser, doc *ast.CommentGroup, iota int) ast.Spec { // 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} + spec := &ast.ValueSpec{ + Doc: doc, + Names: idents, + Type: typ, + Values: values, + Comment: p.lineComment, + } p.declare(spec, iota, p.topScope, ast.Con, idents...) return spec @@ -1946,7 +2098,7 @@ func parseTypeSpec(p *parser, doc *ast.CommentGroup, _ int) ast.Spec { // 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} + spec := &ast.TypeSpec{Doc: doc, Name: ident} p.declare(spec, nil, p.topScope, ast.Typ, ident) spec.Type = p.parseType() @@ -1974,7 +2126,13 @@ func parseVarSpec(p *parser, doc *ast.CommentGroup, _ int) ast.Spec { // 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} + spec := &ast.ValueSpec{ + Doc: doc, + Names: idents, + Type: typ, + Values: values, + Comment: p.lineComment, + } p.declare(spec, nil, p.topScope, ast.Var, idents...) return spec @@ -2001,7 +2159,14 @@ func (p *parser) parseGenDecl(keyword token.Token, f parseSpecFunction) *ast.Gen list = append(list, f(p, nil, 0)) } - return &ast.GenDecl{doc, pos, keyword, lparen, list, rparen} + return &ast.GenDecl{ + Doc: doc, + TokPos: pos, + Tok: keyword, + Lparen: lparen, + Specs: list, + Rparen: rparen, + } } func (p *parser) parseReceiver(scope *ast.Scope) *ast.FieldList { @@ -2014,7 +2179,7 @@ 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{{Type: &ast.BadExpr{par.Opening, par.Closing + 1}}} + par.List = []*ast.Field{{Type: &ast.BadExpr{From: par.Opening, To: par.Closing + 1}}} return par } @@ -2022,8 +2187,13 @@ func (p *parser) parseReceiver(scope *ast.Scope) *ast.FieldList { recv := par.List[0] base := deref(recv.Type) if _, isIdent := base.(*ast.Ident); !isIdent { - p.errorExpected(base.Pos(), "(unqualified) identifier") - par.List = []*ast.Field{{Type: &ast.BadExpr{recv.Pos(), recv.End()}}} + if _, isBad := base.(*ast.BadExpr); !isBad { + // only report error if it's a new one + p.errorExpected(base.Pos(), "(unqualified) identifier") + } + par.List = []*ast.Field{ + {Type: &ast.BadExpr{From: recv.Pos(), To: recv.End()}}, + } } return par @@ -2053,7 +2223,17 @@ func (p *parser) parseFuncDecl() *ast.FuncDecl { } p.expectSemi() - decl := &ast.FuncDecl{doc, recv, ident, &ast.FuncType{pos, params, results}, body} + decl := &ast.FuncDecl{ + Doc: doc, + Recv: recv, + Name: ident, + Type: &ast.FuncType{ + Func: pos, + Params: params, + Results: results, + }, + Body: 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 @@ -2069,7 +2249,7 @@ func (p *parser) parseFuncDecl() *ast.FuncDecl { return decl } -func (p *parser) parseDecl() ast.Decl { +func (p *parser) parseDecl(sync func(*parser)) ast.Decl { if p.trace { defer un(trace(p, "Declaration")) } @@ -2091,9 +2271,8 @@ func (p *parser) parseDecl() ast.Decl { default: pos := p.pos p.errorExpected(pos, "declaration") - p.next() // make progress - decl := &ast.BadDecl{pos, p.pos} - return decl + sync(p) + return &ast.BadDecl{From: pos, To: p.pos} } return p.parseGenDecl(p.tok, f) @@ -2123,7 +2302,7 @@ func (p *parser) parseFile() *ast.File { // 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 { + if p.errors.Len() == 0 && p.mode&PackageClauseOnly == 0 { // import decls for p.tok == token.IMPORT { decls = append(decls, p.parseGenDecl(token.IMPORT, parseImportSpec)) @@ -2132,7 +2311,7 @@ func (p *parser) parseFile() *ast.File { if p.mode&ImportsOnly == 0 { // rest of package body for p.tok != token.EOF { - decls = append(decls, p.parseDecl()) + decls = append(decls, p.parseDecl(syncDecl)) } } } @@ -2151,5 +2330,14 @@ func (p *parser) parseFile() *ast.File { } } - return &ast.File{doc, pos, ident, decls, p.pkgScope, p.imports, p.unresolved[0:i], p.comments} + return &ast.File{ + Doc: doc, + Package: pos, + Name: ident, + Decls: decls, + Scope: p.pkgScope, + Imports: p.imports, + Unresolved: p.unresolved[0:i], + Comments: p.comments, + } } |