mirror of
https://github.com/golang/go.git
synced 2025-05-15 20:34:38 +00:00
5d571cc67e
- ast statements now use interfaces - deleted old (now unused) code R=r OCL=24422 CL=24422
1750 lines
35 KiB
Go
1750 lines
35 KiB
Go
// Copyright 2009 The Go Authors. All rights reserved.
|
|
// Use of this source code is governed by a BSD-style
|
|
// license that can be found in the LICENSE file.
|
|
|
|
package Parser
|
|
|
|
import (
|
|
"flag";
|
|
"fmt";
|
|
"array";
|
|
Scanner "scanner";
|
|
AST "ast";
|
|
)
|
|
|
|
|
|
type Parser struct {
|
|
// Tracing/debugging
|
|
verbose, sixg, deps bool;
|
|
indent uint;
|
|
|
|
// Scanner
|
|
scanner *Scanner.Scanner;
|
|
tokchan <-chan *Scanner.Token;
|
|
comments *array.Array;
|
|
|
|
// Scanner.Token
|
|
pos int; // token source position
|
|
tok int; // one token look-ahead
|
|
val string; // token value (for IDENT, NUMBER, STRING only)
|
|
|
|
// Non-syntactic parser control
|
|
opt_semi bool; // true if semicolon is optional
|
|
|
|
// Nesting levels
|
|
expr_lev int; // 0 = control clause level, 1 = expr inside ()'s
|
|
scope_lev int; // 0 = global scope, 1 = function scope of global functions, etc.
|
|
|
|
// Scopes
|
|
top_scope *AST.Scope;
|
|
};
|
|
|
|
|
|
// ----------------------------------------------------------------------------
|
|
// Elementary support
|
|
|
|
func unimplemented() {
|
|
panic("unimplemented");
|
|
}
|
|
|
|
|
|
func unreachable() {
|
|
panic("unreachable");
|
|
}
|
|
|
|
|
|
func assert(pred bool) {
|
|
if !pred {
|
|
panic("assertion failed");
|
|
}
|
|
}
|
|
|
|
|
|
// ----------------------------------------------------------------------------
|
|
// Parsing support
|
|
|
|
func (P *Parser) PrintIndent() {
|
|
for i := P.indent; i > 0; i-- {
|
|
fmt.Printf(". ");
|
|
}
|
|
}
|
|
|
|
|
|
func (P *Parser) Trace(msg string) {
|
|
P.PrintIndent();
|
|
fmt.Printf("%s {\n", msg);
|
|
P.indent++;
|
|
}
|
|
|
|
|
|
func (P *Parser) Ecart() {
|
|
P.indent--;
|
|
P.PrintIndent();
|
|
fmt.Printf("}\n");
|
|
}
|
|
|
|
|
|
func (P *Parser) VerifyIndent(indent uint) {
|
|
if indent != P.indent {
|
|
panic("imbalanced tracing code");
|
|
}
|
|
}
|
|
|
|
|
|
func (P *Parser) Next0() {
|
|
if P.tokchan == nil {
|
|
P.pos, P.tok, P.val = P.scanner.Scan();
|
|
} else {
|
|
t := <-P.tokchan;
|
|
P.tok, P.pos, P.val = t.Tok, t.Pos, t.Val;
|
|
}
|
|
P.opt_semi = false;
|
|
|
|
if P.verbose {
|
|
P.PrintIndent();
|
|
s := Scanner.TokenString(P.tok);
|
|
// rewrite "{" and "}" so we don't screw up double-click selection
|
|
// in terminal window (we print scopes using the same characters)
|
|
switch s {
|
|
case "{": s = "LBRACE";
|
|
case "}": s = "RBRACE";
|
|
}
|
|
fmt.Printf("[%d] %s\n", P.pos, s);
|
|
}
|
|
}
|
|
|
|
|
|
func (P *Parser) Next() {
|
|
for P.Next0(); P.tok == Scanner.COMMENT; P.Next0() {
|
|
P.comments.Push(AST.NewComment(P.pos, P.val));
|
|
}
|
|
}
|
|
|
|
|
|
func (P *Parser) Open(verbose, sixg, deps bool, scanner *Scanner.Scanner, tokchan <-chan *Scanner.Token) {
|
|
P.verbose = verbose;
|
|
P.sixg = sixg;
|
|
P.deps = deps;
|
|
P.indent = 0;
|
|
|
|
P.scanner = scanner;
|
|
P.tokchan = tokchan;
|
|
P.comments = array.New(0);
|
|
|
|
P.Next();
|
|
P.expr_lev = 0;
|
|
P.scope_lev = 0;
|
|
}
|
|
|
|
|
|
func (P *Parser) Error(pos int, msg string) {
|
|
P.scanner.Error(pos, msg);
|
|
}
|
|
|
|
|
|
func (P *Parser) Expect(tok int) {
|
|
if P.tok != tok {
|
|
msg := "expected '" + Scanner.TokenString(tok) + "', found '" + Scanner.TokenString(P.tok) + "'";
|
|
switch P.tok {
|
|
case Scanner.IDENT, Scanner.INT, Scanner.FLOAT, Scanner.STRING:
|
|
msg += " " + P.val;
|
|
}
|
|
P.Error(P.pos, msg);
|
|
}
|
|
P.Next(); // make progress in any case
|
|
}
|
|
|
|
|
|
func (P *Parser) OptSemicolon() {
|
|
if P.tok == Scanner.SEMICOLON {
|
|
P.Next();
|
|
}
|
|
}
|
|
|
|
|
|
// ----------------------------------------------------------------------------
|
|
// Scopes
|
|
|
|
func (P *Parser) OpenScope() {
|
|
P.top_scope = AST.NewScope(P.top_scope);
|
|
}
|
|
|
|
|
|
func (P *Parser) CloseScope() {
|
|
P.top_scope = P.top_scope.Parent;
|
|
}
|
|
|
|
|
|
func (P *Parser) DeclareInScope(scope *AST.Scope, x AST.Expr, kind int, typ *AST.Type) {
|
|
if P.scope_lev < 0 {
|
|
panic("cannot declare objects in other packages");
|
|
}
|
|
if ident, ok := x.(*AST.Ident); ok { // ignore bad exprs
|
|
obj := ident.Obj;
|
|
obj.Kind = kind;
|
|
obj.Typ = typ;
|
|
obj.Pnolev = P.scope_lev;
|
|
switch {
|
|
case scope.LookupLocal(obj.Ident) == nil:
|
|
scope.Insert(obj);
|
|
case kind == AST.TYPE:
|
|
// possibly a forward declaration
|
|
case kind == AST.FUNC:
|
|
// possibly a forward declaration
|
|
default:
|
|
P.Error(obj.Pos, `"` + obj.Ident + `" is declared already`);
|
|
}
|
|
}
|
|
}
|
|
|
|
|
|
// Declare a comma-separated list of idents or a single ident.
|
|
func (P *Parser) Declare(x AST.Expr, kind int, typ *AST.Type) {
|
|
for {
|
|
p, ok := x.(*AST.BinaryExpr);
|
|
if ok && p.Tok == Scanner.COMMA {
|
|
P.DeclareInScope(P.top_scope, p.X, kind, typ);
|
|
x = p.Y;
|
|
} else {
|
|
break;
|
|
}
|
|
}
|
|
P.DeclareInScope(P.top_scope, x, kind, typ);
|
|
}
|
|
|
|
|
|
// ----------------------------------------------------------------------------
|
|
// AST support
|
|
|
|
func exprType(x AST.Expr) *AST.Type {
|
|
var typ *AST.Type;
|
|
if t, is_type := x.(*AST.TypeLit); is_type {
|
|
typ = t.Typ
|
|
} else if t, is_ident := x.(*AST.Ident); is_ident {
|
|
// assume a type name
|
|
typ = AST.NewType(t.Pos(), AST.TYPENAME);
|
|
typ.Expr = x;
|
|
} else if t, is_selector := x.(*AST.Selector); is_selector && exprType(t.Sel) != nil {
|
|
// possibly a qualified (type) identifier
|
|
typ = AST.NewType(t.Pos(), AST.TYPENAME);
|
|
typ.Expr = x;
|
|
}
|
|
return typ;
|
|
}
|
|
|
|
|
|
func (P *Parser) NoType(x AST.Expr) AST.Expr {
|
|
if x != nil {
|
|
lit, ok := x.(*AST.TypeLit);
|
|
if ok {
|
|
P.Error(lit.Typ.Pos, "expected expression, found type");
|
|
x = &AST.BasicLit{lit.Typ.Pos, Scanner.STRING, ""};
|
|
}
|
|
}
|
|
return x;
|
|
}
|
|
|
|
|
|
func (P *Parser) NewBinary(pos, tok int, x, y AST.Expr) *AST.BinaryExpr {
|
|
return &AST.BinaryExpr{pos, tok, P.NoType(x), P.NoType(y)};
|
|
}
|
|
|
|
|
|
// ----------------------------------------------------------------------------
|
|
// Common productions
|
|
|
|
func (P *Parser) TryType() *AST.Type;
|
|
func (P *Parser) ParseExpression(prec int) AST.Expr;
|
|
func (P *Parser) ParseStatement() AST.Stat;
|
|
func (P *Parser) ParseDeclaration() *AST.Decl;
|
|
|
|
|
|
// If scope != nil, lookup identifier in scope. Otherwise create one.
|
|
func (P *Parser) ParseIdent(scope *AST.Scope) *AST.Ident {
|
|
if P.verbose {
|
|
P.Trace("Ident");
|
|
defer P.Ecart();
|
|
}
|
|
|
|
if P.tok == Scanner.IDENT {
|
|
var obj *AST.Object;
|
|
if scope != nil {
|
|
obj = scope.Lookup(P.val);
|
|
}
|
|
if obj == nil {
|
|
obj = AST.NewObject(P.pos, AST.NONE, P.val);
|
|
} else {
|
|
assert(obj.Kind != AST.NONE);
|
|
}
|
|
x := &AST.Ident{P.pos, obj};
|
|
if P.verbose {
|
|
P.PrintIndent();
|
|
fmt.Printf("ident = \"%s\"\n", P.val);
|
|
}
|
|
P.Next();
|
|
return x;
|
|
}
|
|
|
|
P.Expect(Scanner.IDENT); // use Expect() error handling
|
|
return &AST.Ident{P.pos, nil};
|
|
}
|
|
|
|
|
|
func (P *Parser) ParseIdentList() AST.Expr {
|
|
if P.verbose {
|
|
P.Trace("IdentList");
|
|
defer P.Ecart();
|
|
}
|
|
|
|
var last *AST.BinaryExpr;
|
|
var x AST.Expr = P.ParseIdent(nil);
|
|
for P.tok == Scanner.COMMA {
|
|
pos := P.pos;
|
|
P.Next();
|
|
y := P.ParseIdent(nil);
|
|
if last == nil {
|
|
last = P.NewBinary(pos, Scanner.COMMA, x, y);
|
|
x = last;
|
|
} else {
|
|
last.Y = P.NewBinary(pos, Scanner.COMMA, last.Y, y);
|
|
last = last.Y;
|
|
}
|
|
}
|
|
|
|
return x;
|
|
}
|
|
|
|
|
|
// ----------------------------------------------------------------------------
|
|
// Types
|
|
|
|
func (P *Parser) ParseType() *AST.Type {
|
|
if P.verbose {
|
|
P.Trace("Type");
|
|
defer P.Ecart();
|
|
}
|
|
|
|
t := P.TryType();
|
|
if t == nil {
|
|
P.Error(P.pos, "type expected");
|
|
t = AST.BadType;
|
|
}
|
|
|
|
return t;
|
|
}
|
|
|
|
|
|
func (P *Parser) ParseVarType() *AST.Type {
|
|
if P.verbose {
|
|
P.Trace("VarType");
|
|
defer P.Ecart();
|
|
}
|
|
|
|
return P.ParseType();
|
|
}
|
|
|
|
|
|
func (P *Parser) ParseQualifiedIdent() AST.Expr {
|
|
if P.verbose {
|
|
P.Trace("QualifiedIdent");
|
|
defer P.Ecart();
|
|
}
|
|
|
|
var x AST.Expr = P.ParseIdent(P.top_scope);
|
|
for P.tok == Scanner.PERIOD {
|
|
pos := P.pos;
|
|
P.Next();
|
|
y := P.ParseIdent(nil);
|
|
x = &AST.Selector{pos, x, y};
|
|
}
|
|
|
|
return x;
|
|
}
|
|
|
|
|
|
func (P *Parser) ParseTypeName() *AST.Type {
|
|
if P.verbose {
|
|
P.Trace("TypeName");
|
|
defer P.Ecart();
|
|
}
|
|
|
|
t := AST.NewType(P.pos, AST.TYPENAME);
|
|
t.Expr = P.ParseQualifiedIdent();
|
|
|
|
return t;
|
|
}
|
|
|
|
|
|
func (P *Parser) ParseArrayType() *AST.Type {
|
|
if P.verbose {
|
|
P.Trace("ArrayType");
|
|
defer P.Ecart();
|
|
}
|
|
|
|
t := AST.NewType(P.pos, AST.ARRAY);
|
|
P.Expect(Scanner.LBRACK);
|
|
if P.tok == Scanner.ELLIPSIS {
|
|
t.Expr = P.NewBinary(P.pos, Scanner.ELLIPSIS, nil, nil);
|
|
P.Next();
|
|
} else if P.tok != Scanner.RBRACK {
|
|
t.Expr = P.ParseExpression(1);
|
|
}
|
|
P.Expect(Scanner.RBRACK);
|
|
t.Elt = P.ParseType();
|
|
|
|
return t;
|
|
}
|
|
|
|
|
|
func (P *Parser) ParseChannelType() *AST.Type {
|
|
if P.verbose {
|
|
P.Trace("ChannelType");
|
|
defer P.Ecart();
|
|
}
|
|
|
|
t := AST.NewType(P.pos, AST.CHANNEL);
|
|
t.Mode = AST.FULL;
|
|
if P.tok == Scanner.CHAN {
|
|
P.Next();
|
|
if P.tok == Scanner.ARROW {
|
|
P.Next();
|
|
t.Mode = AST.SEND;
|
|
}
|
|
} else {
|
|
P.Expect(Scanner.ARROW);
|
|
P.Expect(Scanner.CHAN);
|
|
t.Mode = AST.RECV;
|
|
}
|
|
t.Elt = P.ParseVarType();
|
|
|
|
return t;
|
|
}
|
|
|
|
|
|
func (P *Parser) ParseVar(expect_ident bool) *AST.Type {
|
|
t := AST.BadType;
|
|
if expect_ident {
|
|
x := P.ParseIdent(nil);
|
|
t = AST.NewType(x.Pos(), AST.TYPENAME);
|
|
t.Expr = x;
|
|
} else if P.tok == Scanner.ELLIPSIS {
|
|
t = AST.NewType(P.pos, AST.ELLIPSIS);
|
|
P.Next();
|
|
} else {
|
|
t = P.ParseType();
|
|
}
|
|
return t;
|
|
}
|
|
|
|
|
|
func (P *Parser) ParseVarList(list *array.Array, ellipsis_ok bool) {
|
|
if P.verbose {
|
|
P.Trace("VarList");
|
|
defer P.Ecart();
|
|
}
|
|
|
|
// assume a list of types
|
|
// (a list of identifiers looks like a list of type names)
|
|
i0 := list.Len();
|
|
for {
|
|
list.Push(P.ParseVar(ellipsis_ok /* param list */ && i0 > 0));
|
|
if P.tok == Scanner.COMMA {
|
|
P.Next();
|
|
} else {
|
|
break;
|
|
}
|
|
}
|
|
|
|
// if we had a list of identifiers, it must be followed by a type
|
|
typ := P.TryType();
|
|
if typ == nil && P.tok == Scanner.ELLIPSIS {
|
|
typ = AST.NewType(P.pos, AST.ELLIPSIS);
|
|
P.Next();
|
|
}
|
|
|
|
if ellipsis_ok /* param list */ && i0 > 0 && typ == nil {
|
|
// not the first parameter section; we must have a type
|
|
P.Error(P.pos, "type expected");
|
|
typ = AST.BadType;
|
|
}
|
|
|
|
// convert the list into a list of (type) expressions
|
|
if typ != nil {
|
|
// all list entries must be identifiers
|
|
// convert the type entries into identifiers
|
|
for i, n := i0, list.Len(); i < n; i++ {
|
|
t := list.At(i).(*AST.Type);
|
|
if t.Form == AST.TYPENAME {
|
|
if ident, ok := t.Expr.(*AST.Ident); ok {
|
|
list.Set(i, ident);
|
|
continue;
|
|
}
|
|
}
|
|
list.Set(i, &AST.BadExpr{0});
|
|
P.Error(t.Pos, "identifier expected");
|
|
}
|
|
// add type
|
|
list.Push(&AST.TypeLit{typ});
|
|
|
|
} else {
|
|
// all list entries are types
|
|
// convert all type entries into type expressions
|
|
for i, n := i0, list.Len(); i < n; i++ {
|
|
t := list.At(i).(*AST.Type);
|
|
list.Set(i, &AST.TypeLit{t});
|
|
}
|
|
}
|
|
}
|
|
|
|
|
|
func (P *Parser) ParseParameterList(ellipsis_ok bool) *array.Array {
|
|
if P.verbose {
|
|
P.Trace("ParameterList");
|
|
defer P.Ecart();
|
|
}
|
|
|
|
list := array.New(0);
|
|
P.ParseVarList(list, ellipsis_ok);
|
|
for P.tok == Scanner.COMMA {
|
|
P.Next();
|
|
P.ParseVarList(list, ellipsis_ok);
|
|
}
|
|
|
|
return list;
|
|
}
|
|
|
|
|
|
func (P *Parser) ParseParameters(ellipsis_ok bool) *AST.Type {
|
|
if P.verbose {
|
|
P.Trace("Parameters");
|
|
defer P.Ecart();
|
|
}
|
|
|
|
t := AST.NewType(P.pos, AST.STRUCT);
|
|
P.Expect(Scanner.LPAREN);
|
|
if P.tok != Scanner.RPAREN {
|
|
t.List = P.ParseParameterList(ellipsis_ok);
|
|
}
|
|
t.End = P.pos;
|
|
P.Expect(Scanner.RPAREN);
|
|
|
|
return t;
|
|
}
|
|
|
|
|
|
func (P *Parser) ParseResultList() {
|
|
if P.verbose {
|
|
P.Trace("ResultList");
|
|
defer P.Ecart();
|
|
}
|
|
|
|
P.ParseType();
|
|
for P.tok == Scanner.COMMA {
|
|
P.Next();
|
|
P.ParseType();
|
|
}
|
|
if P.tok != Scanner.RPAREN {
|
|
P.ParseType();
|
|
}
|
|
}
|
|
|
|
|
|
func (P *Parser) ParseResult(ftyp *AST.Type) *AST.Type {
|
|
if P.verbose {
|
|
P.Trace("Result");
|
|
defer P.Ecart();
|
|
}
|
|
|
|
var t *AST.Type;
|
|
if P.tok == Scanner.LPAREN {
|
|
t = P.ParseParameters(false);
|
|
} else if P.tok != Scanner.FUNC {
|
|
typ := P.TryType();
|
|
if typ != nil {
|
|
t = AST.NewType(P.pos, AST.STRUCT);
|
|
t.List = array.New(0);
|
|
t.List.Push(&AST.TypeLit{typ});
|
|
t.End = P.pos;
|
|
}
|
|
}
|
|
|
|
return t;
|
|
}
|
|
|
|
|
|
// Function types
|
|
//
|
|
// (params)
|
|
// (params) type
|
|
// (params) (results)
|
|
|
|
func (P *Parser) ParseSignature() *AST.Type {
|
|
if P.verbose {
|
|
P.Trace("Signature");
|
|
defer P.Ecart();
|
|
}
|
|
|
|
P.OpenScope();
|
|
P.scope_lev++;
|
|
|
|
t := AST.NewType(P.pos, AST.FUNCTION);
|
|
t.Scope = P.top_scope;
|
|
t.List = P.ParseParameters(true).List; // TODO find better solution
|
|
t.End = P.pos;
|
|
t.Elt = P.ParseResult(t);
|
|
|
|
P.scope_lev--;
|
|
P.CloseScope();
|
|
|
|
return t;
|
|
}
|
|
|
|
|
|
func (P *Parser) ParseFunctionType() *AST.Type {
|
|
if P.verbose {
|
|
P.Trace("FunctionType");
|
|
defer P.Ecart();
|
|
}
|
|
|
|
P.Expect(Scanner.FUNC);
|
|
return P.ParseSignature();
|
|
}
|
|
|
|
|
|
func (P *Parser) ParseMethodSpec(list *array.Array) {
|
|
if P.verbose {
|
|
P.Trace("MethodDecl");
|
|
defer P.Ecart();
|
|
}
|
|
|
|
list.Push(P.ParseIdentList());
|
|
t := P.ParseSignature();
|
|
list.Push(&AST.TypeLit{t});
|
|
}
|
|
|
|
|
|
func (P *Parser) ParseInterfaceType() *AST.Type {
|
|
if P.verbose {
|
|
P.Trace("InterfaceType");
|
|
defer P.Ecart();
|
|
}
|
|
|
|
t := AST.NewType(P.pos, AST.INTERFACE);
|
|
P.Expect(Scanner.INTERFACE);
|
|
if P.tok == Scanner.LBRACE {
|
|
P.Next();
|
|
P.OpenScope();
|
|
P.scope_lev++;
|
|
|
|
t.List = array.New(0);
|
|
for P.tok == Scanner.IDENT {
|
|
P.ParseMethodSpec(t.List);
|
|
if P.tok != Scanner.RBRACE {
|
|
P.Expect(Scanner.SEMICOLON);
|
|
}
|
|
}
|
|
t.End = P.pos;
|
|
|
|
P.scope_lev--;
|
|
P.CloseScope();
|
|
P.Expect(Scanner.RBRACE);
|
|
}
|
|
|
|
return t;
|
|
}
|
|
|
|
|
|
func (P *Parser) ParseMapType() *AST.Type {
|
|
if P.verbose {
|
|
P.Trace("MapType");
|
|
defer P.Ecart();
|
|
}
|
|
|
|
t := AST.NewType(P.pos, AST.MAP);
|
|
P.Expect(Scanner.MAP);
|
|
P.Expect(Scanner.LBRACK);
|
|
t.Key = P.ParseVarType();
|
|
P.Expect(Scanner.RBRACK);
|
|
t.Elt = P.ParseVarType();
|
|
|
|
return t;
|
|
}
|
|
|
|
|
|
func (P *Parser) ParseOperand() AST.Expr
|
|
|
|
func (P *Parser) ParseStructType() *AST.Type {
|
|
if P.verbose {
|
|
P.Trace("StructType");
|
|
defer P.Ecart();
|
|
}
|
|
|
|
t := AST.NewType(P.pos, AST.STRUCT);
|
|
P.Expect(Scanner.STRUCT);
|
|
if P.tok == Scanner.LBRACE {
|
|
P.Next();
|
|
|
|
t.List = array.New(0);
|
|
t.Scope = AST.NewScope(nil);
|
|
for P.tok != Scanner.RBRACE && P.tok != Scanner.EOF {
|
|
P.ParseVarList(t.List, false);
|
|
if P.tok == Scanner.STRING {
|
|
// ParseOperand takes care of string concatenation
|
|
t.List.Push(P.ParseOperand());
|
|
}
|
|
if P.tok == Scanner.SEMICOLON {
|
|
P.Next();
|
|
} else {
|
|
break;
|
|
}
|
|
}
|
|
P.OptSemicolon();
|
|
t.End = P.pos;
|
|
|
|
P.Expect(Scanner.RBRACE);
|
|
|
|
// enter fields into struct scope
|
|
for i, n := 0, t.List.Len(); i < n; i++ {
|
|
if x, ok := t.List.At(i).(*AST.Ident); ok {
|
|
P.DeclareInScope(t.Scope, x, AST.FIELD, nil);
|
|
}
|
|
}
|
|
}
|
|
|
|
return t;
|
|
}
|
|
|
|
|
|
func (P *Parser) ParsePointerType() *AST.Type {
|
|
if P.verbose {
|
|
P.Trace("PointerType");
|
|
defer P.Ecart();
|
|
}
|
|
|
|
t := AST.NewType(P.pos, AST.POINTER);
|
|
P.Expect(Scanner.MUL);
|
|
t.Elt = P.ParseType();
|
|
|
|
return t;
|
|
}
|
|
|
|
|
|
func (P *Parser) TryType() *AST.Type {
|
|
if P.verbose {
|
|
P.Trace("Type (try)");
|
|
defer P.Ecart();
|
|
}
|
|
|
|
t := AST.BadType;
|
|
switch P.tok {
|
|
case Scanner.IDENT: t = P.ParseTypeName();
|
|
case Scanner.LBRACK: t = P.ParseArrayType();
|
|
case Scanner.CHAN, Scanner.ARROW: t = P.ParseChannelType();
|
|
case Scanner.INTERFACE: t = P.ParseInterfaceType();
|
|
case Scanner.FUNC: t = P.ParseFunctionType();
|
|
case Scanner.MAP: t = P.ParseMapType();
|
|
case Scanner.STRUCT: t = P.ParseStructType();
|
|
case Scanner.MUL: t = P.ParsePointerType();
|
|
default: t = nil; // no type found
|
|
}
|
|
return t;
|
|
}
|
|
|
|
|
|
// ----------------------------------------------------------------------------
|
|
// Blocks
|
|
|
|
|
|
func (P *Parser) ParseStatementList(list *array.Array) {
|
|
if P.verbose {
|
|
P.Trace("StatementList");
|
|
defer P.Ecart();
|
|
defer P.VerifyIndent(P.indent);
|
|
}
|
|
|
|
for P.tok != Scanner.CASE && P.tok != Scanner.DEFAULT && P.tok != Scanner.RBRACE && P.tok != Scanner.EOF {
|
|
s := P.ParseStatement();
|
|
if s != nil {
|
|
// not the empty statement
|
|
list.Push(s);
|
|
}
|
|
if P.tok == Scanner.SEMICOLON {
|
|
P.Next();
|
|
} else if P.opt_semi {
|
|
P.opt_semi = false; // "consume" optional semicolon
|
|
} else {
|
|
break;
|
|
}
|
|
}
|
|
|
|
// Try to provide a good error message
|
|
if P.tok != Scanner.CASE && P.tok != Scanner.DEFAULT && P.tok != Scanner.RBRACE && P.tok != Scanner.EOF {
|
|
P.Error(P.pos, "expected end of statement list (semicolon missing?)");
|
|
}
|
|
}
|
|
|
|
|
|
func (P *Parser) ParseBlock(ftyp *AST.Type, tok int) *AST.Block {
|
|
if P.verbose {
|
|
P.Trace("Block");
|
|
defer P.Ecart();
|
|
}
|
|
|
|
b := AST.NewBlock(P.pos, tok);
|
|
P.Expect(tok);
|
|
|
|
P.OpenScope();
|
|
// enter recv and parameters into function scope
|
|
if ftyp != nil {
|
|
assert(ftyp.Form == AST.FUNCTION);
|
|
if ftyp.Key != nil {
|
|
}
|
|
if ftyp.List != nil {
|
|
for i, n := 0, ftyp.List.Len(); i < n; i++ {
|
|
if x, ok := ftyp.List.At(i).(*AST.Ident); ok {
|
|
P.DeclareInScope(P.top_scope, x, AST.VAR, nil);
|
|
}
|
|
}
|
|
}
|
|
}
|
|
|
|
P.ParseStatementList(b.List);
|
|
P.CloseScope();
|
|
|
|
if tok == Scanner.LBRACE {
|
|
b.End = P.pos;
|
|
P.Expect(Scanner.RBRACE);
|
|
P.opt_semi = true;
|
|
}
|
|
|
|
return b;
|
|
}
|
|
|
|
|
|
// ----------------------------------------------------------------------------
|
|
// Expressions
|
|
|
|
func (P *Parser) ParseExpressionList() AST.Expr {
|
|
if P.verbose {
|
|
P.Trace("ExpressionList");
|
|
defer P.Ecart();
|
|
}
|
|
|
|
x := P.ParseExpression(1);
|
|
for first := true; P.tok == Scanner.COMMA; {
|
|
pos := P.pos;
|
|
P.Next();
|
|
y := P.ParseExpression(1);
|
|
if first {
|
|
x = P.NewBinary(pos, Scanner.COMMA, x, y);
|
|
first = false;
|
|
} else {
|
|
x.(*AST.BinaryExpr).Y = P.NewBinary(pos, Scanner.COMMA, x.(*AST.BinaryExpr).Y, y);
|
|
}
|
|
}
|
|
|
|
return x;
|
|
}
|
|
|
|
|
|
func (P *Parser) ParseFunctionLit() AST.Expr {
|
|
if P.verbose {
|
|
P.Trace("FunctionLit");
|
|
defer P.Ecart();
|
|
}
|
|
|
|
pos := P.pos;
|
|
P.Expect(Scanner.FUNC);
|
|
typ := P.ParseSignature();
|
|
P.expr_lev++;
|
|
P.scope_lev++;
|
|
body := P.ParseBlock(typ, Scanner.LBRACE);
|
|
P.scope_lev--;
|
|
P.expr_lev--;
|
|
|
|
return &AST.FunctionLit{pos, typ, body};
|
|
}
|
|
|
|
|
|
func (P *Parser) ParseOperand() AST.Expr {
|
|
if P.verbose {
|
|
P.Trace("Operand");
|
|
defer P.Ecart();
|
|
}
|
|
|
|
switch P.tok {
|
|
case Scanner.IDENT:
|
|
return P.ParseIdent(P.top_scope);
|
|
|
|
case Scanner.LPAREN:
|
|
// TODO we could have a function type here as in: new(())
|
|
// (currently not working)
|
|
P.Next();
|
|
P.expr_lev++;
|
|
x := P.ParseExpression(1);
|
|
P.expr_lev--;
|
|
P.Expect(Scanner.RPAREN);
|
|
return x;
|
|
|
|
case Scanner.INT, Scanner.FLOAT, Scanner.STRING:
|
|
x := &AST.BasicLit{P.pos, P.tok, P.val};
|
|
P.Next();
|
|
if x.Tok == Scanner.STRING {
|
|
// TODO should remember the list instead of
|
|
// concatenate the strings here
|
|
for ; P.tok == Scanner.STRING; P.Next() {
|
|
x.Val += P.val;
|
|
}
|
|
}
|
|
return x;
|
|
|
|
case Scanner.FUNC:
|
|
return P.ParseFunctionLit();
|
|
|
|
default:
|
|
t := P.TryType();
|
|
if t != nil {
|
|
return &AST.TypeLit{t};
|
|
} else {
|
|
P.Error(P.pos, "operand expected");
|
|
P.Next(); // make progress
|
|
}
|
|
}
|
|
|
|
return &AST.BadExpr{P.pos};
|
|
}
|
|
|
|
|
|
func (P *Parser) ParseSelectorOrTypeGuard(x AST.Expr) AST.Expr {
|
|
if P.verbose {
|
|
P.Trace("SelectorOrTypeGuard");
|
|
defer P.Ecart();
|
|
}
|
|
|
|
pos := P.pos;
|
|
P.Expect(Scanner.PERIOD);
|
|
|
|
if P.tok == Scanner.IDENT {
|
|
x = &AST.Selector{pos, x, P.ParseIdent(nil)};
|
|
|
|
} else {
|
|
P.Expect(Scanner.LPAREN);
|
|
x = &AST.TypeGuard{pos, x, P.ParseType()};
|
|
P.Expect(Scanner.RPAREN);
|
|
}
|
|
|
|
return x;
|
|
}
|
|
|
|
|
|
func (P *Parser) ParseIndex(x AST.Expr) AST.Expr {
|
|
if P.verbose {
|
|
P.Trace("IndexOrSlice");
|
|
defer P.Ecart();
|
|
}
|
|
|
|
pos := P.pos;
|
|
P.Expect(Scanner.LBRACK);
|
|
P.expr_lev++;
|
|
i := P.ParseExpression(0);
|
|
P.expr_lev--;
|
|
P.Expect(Scanner.RBRACK);
|
|
|
|
return &AST.Index{pos, x, i};
|
|
}
|
|
|
|
|
|
func (P *Parser) ParseBinaryExpr(prec1 int) AST.Expr
|
|
|
|
func (P *Parser) ParseCall(f AST.Expr) AST.Expr {
|
|
if P.verbose {
|
|
P.Trace("Call");
|
|
defer P.Ecart();
|
|
}
|
|
|
|
call := &AST.Call{P.pos, f, nil};
|
|
P.Expect(Scanner.LPAREN);
|
|
if P.tok != Scanner.RPAREN {
|
|
P.expr_lev++;
|
|
var t *AST.Type;
|
|
if x0, ok := f.(*AST.Ident); ok && (x0.Obj.Ident == "new" || x0.Obj.Ident == "make") {
|
|
// heuristic: assume it's a new(T) or make(T, ...) call, try to parse a type
|
|
t = P.TryType();
|
|
}
|
|
if t != nil {
|
|
// we found a type
|
|
args := &AST.TypeLit{t};
|
|
if P.tok == Scanner.COMMA {
|
|
pos := P.pos;
|
|
P.Next();
|
|
y := P.ParseExpressionList();
|
|
// create list manually because NewExpr checks for type expressions
|
|
args := &AST.BinaryExpr{pos, Scanner.COMMA, args, y};
|
|
}
|
|
call.Args = args;
|
|
} else {
|
|
// normal argument list
|
|
call.Args = P.ParseExpressionList();
|
|
}
|
|
P.expr_lev--;
|
|
}
|
|
P.Expect(Scanner.RPAREN);
|
|
|
|
return call;
|
|
}
|
|
|
|
|
|
func (P *Parser) ParseCompositeElements() AST.Expr {
|
|
x := P.ParseExpression(0);
|
|
if P.tok == Scanner.COMMA {
|
|
pos := P.pos;
|
|
P.Next();
|
|
|
|
// first element determines mode
|
|
singles := true;
|
|
if t, is_binary := x.(*AST.BinaryExpr); is_binary && t.Tok == Scanner.COLON {
|
|
singles = false;
|
|
}
|
|
|
|
var last *AST.BinaryExpr;
|
|
for P.tok != Scanner.RBRACE && P.tok != Scanner.EOF {
|
|
y := P.ParseExpression(0);
|
|
|
|
if singles {
|
|
if t, is_binary := y.(*AST.BinaryExpr); is_binary && t.Tok == Scanner.COLON {
|
|
P.Error(t.X.Pos(), "single value expected; found pair");
|
|
}
|
|
} else {
|
|
if t, is_binary := y.(*AST.BinaryExpr); !is_binary || t.Tok != Scanner.COLON {
|
|
P.Error(y.Pos(), "key:value pair expected; found single value");
|
|
}
|
|
}
|
|
|
|
if last == nil {
|
|
last = P.NewBinary(pos, Scanner.COMMA, x, y);
|
|
x = last;
|
|
} else {
|
|
last.Y = P.NewBinary(pos, Scanner.COMMA, last.Y, y);
|
|
last = last.Y;
|
|
}
|
|
|
|
if P.tok == Scanner.COMMA {
|
|
pos = P.pos;
|
|
P.Next();
|
|
} else {
|
|
break;
|
|
}
|
|
|
|
}
|
|
}
|
|
return x;
|
|
}
|
|
|
|
|
|
func (P *Parser) ParseCompositeLit(t *AST.Type) AST.Expr {
|
|
if P.verbose {
|
|
P.Trace("CompositeLit");
|
|
defer P.Ecart();
|
|
}
|
|
|
|
pos := P.pos;
|
|
P.Expect(Scanner.LBRACE);
|
|
var elts AST.Expr;
|
|
if P.tok != Scanner.RBRACE {
|
|
elts = P.ParseCompositeElements();
|
|
}
|
|
P.Expect(Scanner.RBRACE);
|
|
|
|
return &AST.CompositeLit{pos, t, elts};
|
|
}
|
|
|
|
|
|
func (P *Parser) ParsePrimaryExpr() AST.Expr {
|
|
if P.verbose {
|
|
P.Trace("PrimaryExpr");
|
|
defer P.Ecart();
|
|
}
|
|
|
|
x := P.ParseOperand();
|
|
for {
|
|
switch P.tok {
|
|
case Scanner.PERIOD: x = P.ParseSelectorOrTypeGuard(x);
|
|
case Scanner.LBRACK: x = P.ParseIndex(x);
|
|
case Scanner.LPAREN: x = P.ParseCall(x);
|
|
case Scanner.LBRACE:
|
|
// assume a composite literal only if x could be a type
|
|
// and if we are not inside a control clause (expr_lev >= 0)
|
|
// (composites inside control clauses must be parenthesized)
|
|
var t *AST.Type;
|
|
if P.expr_lev >= 0 {
|
|
t = exprType(x);
|
|
}
|
|
if t != nil {
|
|
x = P.ParseCompositeLit(t);
|
|
} else {
|
|
return x;
|
|
}
|
|
default:
|
|
return x;
|
|
}
|
|
}
|
|
|
|
unreachable();
|
|
return nil;
|
|
}
|
|
|
|
|
|
func (P *Parser) ParseUnaryExpr() AST.Expr {
|
|
if P.verbose {
|
|
P.Trace("UnaryExpr");
|
|
defer P.Ecart();
|
|
}
|
|
|
|
switch P.tok {
|
|
case Scanner.ADD, Scanner.SUB, Scanner.MUL, Scanner.NOT, Scanner.XOR, Scanner.ARROW, Scanner.AND:
|
|
pos, tok := P.pos, P.tok;
|
|
P.Next();
|
|
y := P.ParseUnaryExpr();
|
|
if lit, ok := y.(*AST.TypeLit); ok && tok == Scanner.MUL {
|
|
// pointer type
|
|
t := AST.NewType(pos, AST.POINTER);
|
|
t.Elt = lit.Typ;
|
|
return &AST.TypeLit{t};
|
|
} else {
|
|
return &AST.UnaryExpr{pos, tok, y};
|
|
}
|
|
}
|
|
|
|
return P.ParsePrimaryExpr();
|
|
}
|
|
|
|
|
|
func (P *Parser) ParseBinaryExpr(prec1 int) AST.Expr {
|
|
if P.verbose {
|
|
P.Trace("BinaryExpr");
|
|
defer P.Ecart();
|
|
}
|
|
|
|
x := P.ParseUnaryExpr();
|
|
for prec := Scanner.Precedence(P.tok); prec >= prec1; prec-- {
|
|
for Scanner.Precedence(P.tok) == prec {
|
|
pos, tok := P.pos, P.tok;
|
|
P.Next();
|
|
y := P.ParseBinaryExpr(prec + 1);
|
|
x = P.NewBinary(pos, tok, x, y);
|
|
}
|
|
}
|
|
|
|
return x;
|
|
}
|
|
|
|
|
|
func (P *Parser) ParseExpression(prec int) AST.Expr {
|
|
if P.verbose {
|
|
P.Trace("Expression");
|
|
defer P.Ecart();
|
|
defer P.VerifyIndent(P.indent);
|
|
}
|
|
|
|
if prec < 0 {
|
|
panic("precedence must be >= 0");
|
|
}
|
|
|
|
return P.NoType(P.ParseBinaryExpr(prec));
|
|
}
|
|
|
|
|
|
// ----------------------------------------------------------------------------
|
|
// Statements
|
|
|
|
func (P *Parser) ParseSimpleStat(range_ok bool) AST.Stat {
|
|
if P.verbose {
|
|
P.Trace("SimpleStat");
|
|
defer P.Ecart();
|
|
}
|
|
|
|
x := P.ParseExpressionList();
|
|
|
|
switch P.tok {
|
|
case Scanner.COLON:
|
|
// label declaration
|
|
pos := P.pos;
|
|
P.Next(); // consume ":"
|
|
P.opt_semi = true;
|
|
if AST.ExprLen(x) == 1 {
|
|
if label, is_ident := x.(*AST.Ident); is_ident {
|
|
return &AST.LabelDecl{pos, label};
|
|
}
|
|
}
|
|
P.Error(x.Pos(), "illegal label declaration");
|
|
return nil;
|
|
|
|
case
|
|
Scanner.DEFINE, Scanner.ASSIGN, Scanner.ADD_ASSIGN,
|
|
Scanner.SUB_ASSIGN, Scanner.MUL_ASSIGN, Scanner.QUO_ASSIGN,
|
|
Scanner.REM_ASSIGN, Scanner.AND_ASSIGN, Scanner.OR_ASSIGN,
|
|
Scanner.XOR_ASSIGN, Scanner.SHL_ASSIGN, Scanner.SHR_ASSIGN:
|
|
// declaration/assignment
|
|
pos, tok := P.pos, P.tok;
|
|
P.Next();
|
|
var y AST.Expr;
|
|
if range_ok && P.tok == Scanner.RANGE {
|
|
range_pos := P.pos;
|
|
P.Next();
|
|
y = &AST.UnaryExpr{range_pos, Scanner.RANGE, P.ParseExpression(1)};
|
|
if tok != Scanner.DEFINE && tok != Scanner.ASSIGN {
|
|
P.Error(pos, "expected '=' or ':=', found '" + Scanner.TokenString(tok) + "'");
|
|
}
|
|
} else {
|
|
y = P.ParseExpressionList();
|
|
if xl, yl := AST.ExprLen(x), AST.ExprLen(y); xl > 1 && yl > 1 && xl != yl {
|
|
P.Error(x.Pos(), "arity of lhs doesn't match rhs");
|
|
}
|
|
}
|
|
// TODO changed ILLEGAL -> NONE
|
|
return &AST.ExpressionStat{x.Pos(), Scanner.ILLEGAL, P.NewBinary(pos, tok, x, y)};
|
|
|
|
default:
|
|
if AST.ExprLen(x) != 1 {
|
|
P.Error(x.Pos(), "only one expression allowed");
|
|
}
|
|
|
|
if P.tok == Scanner.INC || P.tok == Scanner.DEC {
|
|
s := &AST.ExpressionStat{P.pos, P.tok, x};
|
|
P.Next(); // consume "++" or "--"
|
|
return s;
|
|
}
|
|
|
|
// TODO changed ILLEGAL -> NONE
|
|
return &AST.ExpressionStat{x.Pos(), Scanner.ILLEGAL, x};
|
|
}
|
|
|
|
unreachable();
|
|
return nil;
|
|
}
|
|
|
|
|
|
func (P *Parser) ParseInvocationStat(keyword int) *AST.ExpressionStat {
|
|
if P.verbose {
|
|
P.Trace("InvocationStat");
|
|
defer P.Ecart();
|
|
}
|
|
|
|
pos := P.pos;
|
|
P.Expect(keyword);
|
|
return &AST.ExpressionStat{pos, keyword, P.ParseExpression(1)};
|
|
}
|
|
|
|
|
|
func (P *Parser) ParseReturnStat() *AST.ExpressionStat {
|
|
if P.verbose {
|
|
P.Trace("ReturnStat");
|
|
defer P.Ecart();
|
|
}
|
|
|
|
pos := P.pos;
|
|
P.Expect(Scanner.RETURN);
|
|
var x AST.Expr;
|
|
if P.tok != Scanner.SEMICOLON && P.tok != Scanner.RBRACE {
|
|
x = P.ParseExpressionList();
|
|
}
|
|
|
|
return &AST.ExpressionStat{pos, Scanner.RETURN, x};
|
|
}
|
|
|
|
|
|
func (P *Parser) ParseControlFlowStat(tok int) *AST.ControlFlowStat {
|
|
if P.verbose {
|
|
P.Trace("ControlFlowStat");
|
|
defer P.Ecart();
|
|
}
|
|
|
|
s := &AST.ControlFlowStat{P.pos, tok, nil};
|
|
P.Expect(tok);
|
|
if tok != Scanner.FALLTHROUGH && P.tok == Scanner.IDENT {
|
|
s.Label = P.ParseIdent(P.top_scope);
|
|
}
|
|
|
|
return s;
|
|
}
|
|
|
|
|
|
func (P *Parser) ParseControlClause(isForStat bool) (init AST.Stat, expr AST.Expr, post AST.Stat) {
|
|
if P.verbose {
|
|
P.Trace("ControlClause");
|
|
defer P.Ecart();
|
|
}
|
|
|
|
if P.tok != Scanner.LBRACE {
|
|
prev_lev := P.expr_lev;
|
|
P.expr_lev = -1;
|
|
if P.tok != Scanner.SEMICOLON {
|
|
init = P.ParseSimpleStat(isForStat);
|
|
// TODO check for range clause and exit if found
|
|
}
|
|
if P.tok == Scanner.SEMICOLON {
|
|
P.Next();
|
|
if P.tok != Scanner.SEMICOLON && P.tok != Scanner.LBRACE {
|
|
expr = P.ParseExpression(1);
|
|
}
|
|
if isForStat {
|
|
P.Expect(Scanner.SEMICOLON);
|
|
if P.tok != Scanner.LBRACE {
|
|
post = P.ParseSimpleStat(false);
|
|
}
|
|
}
|
|
} else {
|
|
if init != nil { // guard in case of errors
|
|
if s, is_expr_stat := init.(*AST.ExpressionStat); is_expr_stat {
|
|
expr, init = s.Expr, nil;
|
|
} else {
|
|
P.Error(0, "illegal control clause");
|
|
}
|
|
}
|
|
}
|
|
P.expr_lev = prev_lev;
|
|
}
|
|
|
|
return init, expr, post;
|
|
}
|
|
|
|
|
|
func (P *Parser) ParseIfStat() *AST.IfStat {
|
|
if P.verbose {
|
|
P.Trace("IfStat");
|
|
defer P.Ecart();
|
|
}
|
|
|
|
P.OpenScope();
|
|
pos := P.pos;
|
|
P.Expect(Scanner.IF);
|
|
init, cond, dummy := P.ParseControlClause(false);
|
|
body := P.ParseBlock(nil, Scanner.LBRACE);
|
|
var else_ AST.Stat;
|
|
if P.tok == Scanner.ELSE {
|
|
P.Next();
|
|
if P.tok == Scanner.IF || P.tok == Scanner.LBRACE {
|
|
else_ = P.ParseStatement();
|
|
} else if P.sixg {
|
|
else_ = P.ParseStatement();
|
|
if else_ != nil {
|
|
// not the empty statement
|
|
// wrap in a block since we don't have one
|
|
body := AST.NewBlock(0, Scanner.LBRACE);
|
|
body.List.Push(else_);
|
|
else_ = &AST.CompositeStat{body};
|
|
}
|
|
} else {
|
|
P.Error(P.pos, "'if' or '{' expected - illegal 'else' branch");
|
|
}
|
|
}
|
|
P.CloseScope();
|
|
|
|
return &AST.IfStat{pos, init, cond, body, else_ };
|
|
}
|
|
|
|
|
|
func (P *Parser) ParseForStat() *AST.ForStat {
|
|
if P.verbose {
|
|
P.Trace("ForStat");
|
|
defer P.Ecart();
|
|
}
|
|
|
|
P.OpenScope();
|
|
pos := P.pos;
|
|
P.Expect(Scanner.FOR);
|
|
init, cond, post := P.ParseControlClause(true);
|
|
body := P.ParseBlock(nil, Scanner.LBRACE);
|
|
P.CloseScope();
|
|
|
|
return &AST.ForStat{pos, init, cond, post, body};
|
|
}
|
|
|
|
|
|
func (P *Parser) ParseCaseClause() *AST.CaseClause {
|
|
if P.verbose {
|
|
P.Trace("CaseClause");
|
|
defer P.Ecart();
|
|
}
|
|
|
|
// SwitchCase
|
|
pos := P.pos;
|
|
var expr AST.Expr;
|
|
if P.tok == Scanner.CASE {
|
|
P.Next();
|
|
expr = P.ParseExpressionList();
|
|
} else {
|
|
P.Expect(Scanner.DEFAULT);
|
|
}
|
|
|
|
return &AST.CaseClause{pos, expr, P.ParseBlock(nil, Scanner.COLON)};
|
|
}
|
|
|
|
|
|
func (P *Parser) ParseSwitchStat() *AST.SwitchStat {
|
|
if P.verbose {
|
|
P.Trace("SwitchStat");
|
|
defer P.Ecart();
|
|
}
|
|
|
|
P.OpenScope();
|
|
pos := P.pos;
|
|
P.Expect(Scanner.SWITCH);
|
|
init, tag, post := P.ParseControlClause(false);
|
|
body := AST.NewBlock(P.pos, Scanner.LBRACE);
|
|
P.Expect(Scanner.LBRACE);
|
|
for P.tok != Scanner.RBRACE && P.tok != Scanner.EOF {
|
|
body.List.Push(P.ParseCaseClause());
|
|
}
|
|
body.End = P.pos;
|
|
P.Expect(Scanner.RBRACE);
|
|
P.opt_semi = true;
|
|
P.CloseScope();
|
|
|
|
return &AST.SwitchStat{pos, init, tag, body};
|
|
}
|
|
|
|
|
|
func (P *Parser) ParseCommClause() *AST.CaseClause {
|
|
if P.verbose {
|
|
P.Trace("CommClause");
|
|
defer P.Ecart();
|
|
}
|
|
|
|
// CommCase
|
|
pos := P.pos;
|
|
var expr AST.Expr;
|
|
if P.tok == Scanner.CASE {
|
|
P.Next();
|
|
x := P.ParseExpression(1);
|
|
if P.tok == Scanner.ASSIGN || P.tok == Scanner.DEFINE {
|
|
pos, tok := P.pos, P.tok;
|
|
P.Next();
|
|
if P.tok == Scanner.ARROW {
|
|
y := P.ParseExpression(1);
|
|
x = P.NewBinary(pos, tok, x, y);
|
|
} else {
|
|
P.Expect(Scanner.ARROW); // use Expect() error handling
|
|
}
|
|
}
|
|
expr = x;
|
|
} else {
|
|
P.Expect(Scanner.DEFAULT);
|
|
}
|
|
|
|
return &AST.CaseClause{pos, expr, P.ParseBlock(nil, Scanner.COLON)};
|
|
}
|
|
|
|
|
|
func (P *Parser) ParseSelectStat() *AST.SelectStat {
|
|
if P.verbose {
|
|
P.Trace("SelectStat");
|
|
defer P.Ecart();
|
|
}
|
|
|
|
P.OpenScope();
|
|
pos := P.pos;
|
|
P.Expect(Scanner.SELECT);
|
|
body := AST.NewBlock(P.pos, Scanner.LBRACE);
|
|
P.Expect(Scanner.LBRACE);
|
|
for P.tok != Scanner.RBRACE && P.tok != Scanner.EOF {
|
|
body.List.Push(P.ParseCommClause());
|
|
}
|
|
body.End = P.pos;
|
|
P.Expect(Scanner.RBRACE);
|
|
P.opt_semi = true;
|
|
P.CloseScope();
|
|
|
|
return &AST.SelectStat{pos, body};
|
|
}
|
|
|
|
|
|
func (P *Parser) ParseStatement() AST.Stat {
|
|
if P.verbose {
|
|
P.Trace("Statement");
|
|
defer P.Ecart();
|
|
defer P.VerifyIndent(P.indent);
|
|
}
|
|
|
|
switch P.tok {
|
|
case Scanner.CONST, Scanner.TYPE, Scanner.VAR:
|
|
return &AST.DeclarationStat{P.ParseDeclaration()};
|
|
case Scanner.FUNC:
|
|
// for now we do not allow local function declarations,
|
|
// instead we assume this starts a function literal
|
|
fallthrough;
|
|
case
|
|
// only the tokens that are legal top-level expression starts
|
|
Scanner.IDENT, Scanner.INT, Scanner.FLOAT, Scanner.STRING, Scanner.LPAREN, // operand
|
|
Scanner.LBRACK, Scanner.STRUCT, // composite type
|
|
Scanner.MUL, Scanner.AND, Scanner.ARROW: // unary
|
|
return P.ParseSimpleStat(false);
|
|
case Scanner.GO, Scanner.DEFER:
|
|
return P.ParseInvocationStat(P.tok);
|
|
case Scanner.RETURN:
|
|
return P.ParseReturnStat();
|
|
case Scanner.BREAK, Scanner.CONTINUE, Scanner.GOTO, Scanner.FALLTHROUGH:
|
|
return P.ParseControlFlowStat(P.tok);
|
|
case Scanner.LBRACE:
|
|
return &AST.CompositeStat{P.ParseBlock(nil, Scanner.LBRACE)};
|
|
case Scanner.IF:
|
|
return P.ParseIfStat();
|
|
case Scanner.FOR:
|
|
return P.ParseForStat();
|
|
case Scanner.SWITCH:
|
|
return P.ParseSwitchStat();
|
|
case Scanner.SELECT:
|
|
return P.ParseSelectStat();
|
|
}
|
|
|
|
// empty statement
|
|
return nil;
|
|
}
|
|
|
|
|
|
// ----------------------------------------------------------------------------
|
|
// Declarations
|
|
|
|
func (P *Parser) ParseImportSpec(d *AST.Decl) {
|
|
if P.verbose {
|
|
P.Trace("ImportSpec");
|
|
defer P.Ecart();
|
|
}
|
|
|
|
if P.tok == Scanner.PERIOD {
|
|
P.Error(P.pos, `"import ." not yet handled properly`);
|
|
P.Next();
|
|
} else if P.tok == Scanner.IDENT {
|
|
d.Ident = P.ParseIdent(nil);
|
|
}
|
|
|
|
if P.tok == Scanner.STRING {
|
|
// TODO eventually the scanner should strip the quotes
|
|
d.Val = &AST.BasicLit{P.pos, Scanner.STRING, P.val};
|
|
P.Next();
|
|
} else {
|
|
P.Expect(Scanner.STRING); // use Expect() error handling
|
|
}
|
|
}
|
|
|
|
|
|
func (P *Parser) ParseConstSpec(d *AST.Decl) {
|
|
if P.verbose {
|
|
P.Trace("ConstSpec");
|
|
defer P.Ecart();
|
|
}
|
|
|
|
d.Ident = P.ParseIdentList();
|
|
d.Typ = P.TryType();
|
|
if P.tok == Scanner.ASSIGN {
|
|
P.Next();
|
|
d.Val = P.ParseExpressionList();
|
|
}
|
|
}
|
|
|
|
|
|
func (P *Parser) ParseTypeSpec(d *AST.Decl) {
|
|
if P.verbose {
|
|
P.Trace("TypeSpec");
|
|
defer P.Ecart();
|
|
}
|
|
|
|
d.Ident = P.ParseIdent(nil);
|
|
d.Typ = P.ParseType();
|
|
P.opt_semi = true;
|
|
}
|
|
|
|
|
|
func (P *Parser) ParseVarSpec(d *AST.Decl) {
|
|
if P.verbose {
|
|
P.Trace("VarSpec");
|
|
defer P.Ecart();
|
|
}
|
|
|
|
d.Ident = P.ParseIdentList();
|
|
if P.tok == Scanner.ASSIGN {
|
|
P.Next();
|
|
d.Val = P.ParseExpressionList();
|
|
} else {
|
|
d.Typ = P.ParseVarType();
|
|
if P.tok == Scanner.ASSIGN {
|
|
P.Next();
|
|
d.Val = P.ParseExpressionList();
|
|
}
|
|
}
|
|
}
|
|
|
|
|
|
func (P *Parser) ParseSpec(d *AST.Decl) {
|
|
kind := AST.NONE;
|
|
|
|
switch d.Tok {
|
|
case Scanner.IMPORT: P.ParseImportSpec(d); kind = AST.PACKAGE;
|
|
case Scanner.CONST: P.ParseConstSpec(d); kind = AST.CONST;
|
|
case Scanner.TYPE: P.ParseTypeSpec(d); kind = AST.TYPE;
|
|
case Scanner.VAR: P.ParseVarSpec(d); kind = AST.VAR;
|
|
default: unreachable();
|
|
}
|
|
|
|
// semantic checks
|
|
if d.Tok == Scanner.IMPORT {
|
|
if d.Ident != nil {
|
|
P.Declare(d.Ident, kind, nil);
|
|
}
|
|
} else {
|
|
P.Declare(d.Ident, kind, d.Typ);
|
|
if d.Val != nil {
|
|
// initialization/assignment
|
|
llen := AST.ExprLen(d.Ident);
|
|
rlen := AST.ExprLen(d.Val);
|
|
if llen == rlen {
|
|
// TODO
|
|
} else if rlen == 1 {
|
|
// TODO
|
|
} else {
|
|
if llen < rlen {
|
|
P.Error(AST.ExprAt(d.Val, llen).Pos(), "more expressions than variables");
|
|
} else {
|
|
P.Error(AST.ExprAt(d.Ident, rlen).Pos(), "more variables than expressions");
|
|
}
|
|
}
|
|
} else {
|
|
// TODO
|
|
}
|
|
}
|
|
}
|
|
|
|
|
|
func (P *Parser) ParseDecl(keyword int) *AST.Decl {
|
|
if P.verbose {
|
|
P.Trace("Decl");
|
|
defer P.Ecart();
|
|
}
|
|
|
|
d := AST.NewDecl(P.pos, keyword);
|
|
P.Expect(keyword);
|
|
if P.tok == Scanner.LPAREN {
|
|
P.Next();
|
|
d.List = array.New(0);
|
|
for P.tok != Scanner.RPAREN && P.tok != Scanner.EOF {
|
|
d1 := AST.NewDecl(P.pos, keyword);
|
|
P.ParseSpec(d1);
|
|
d.List.Push(d1);
|
|
if P.tok == Scanner.SEMICOLON {
|
|
P.Next();
|
|
} else {
|
|
break;
|
|
}
|
|
}
|
|
d.End = P.pos;
|
|
P.Expect(Scanner.RPAREN);
|
|
P.opt_semi = true;
|
|
|
|
} else {
|
|
P.ParseSpec(d);
|
|
}
|
|
|
|
return d;
|
|
}
|
|
|
|
|
|
// Function declarations
|
|
//
|
|
// func ident (params)
|
|
// func ident (params) type
|
|
// func ident (params) (results)
|
|
// func (recv) ident (params)
|
|
// func (recv) ident (params) type
|
|
// func (recv) ident (params) (results)
|
|
|
|
func (P *Parser) ParseFunctionDecl() *AST.Decl {
|
|
if P.verbose {
|
|
P.Trace("FunctionDecl");
|
|
defer P.Ecart();
|
|
}
|
|
|
|
d := AST.NewDecl(P.pos, Scanner.FUNC);
|
|
P.Expect(Scanner.FUNC);
|
|
|
|
var recv *AST.Type;
|
|
if P.tok == Scanner.LPAREN {
|
|
pos := P.pos;
|
|
recv = P.ParseParameters(true);
|
|
if recv.Nfields() != 1 {
|
|
P.Error(pos, "must have exactly one receiver");
|
|
}
|
|
}
|
|
|
|
ident := P.ParseIdent(nil);
|
|
d.Ident = ident;
|
|
d.Typ = P.ParseSignature();
|
|
d.Typ.Key = recv;
|
|
|
|
if P.tok == Scanner.LBRACE {
|
|
d.Body = P.ParseBlock(d.Typ, Scanner.LBRACE);
|
|
}
|
|
|
|
return d;
|
|
}
|
|
|
|
|
|
func (P *Parser) ParseDeclaration() *AST.Decl {
|
|
if P.verbose {
|
|
P.Trace("Declaration");
|
|
defer P.Ecart();
|
|
defer P.VerifyIndent(P.indent);
|
|
}
|
|
indent := P.indent;
|
|
|
|
d := AST.BadDecl;
|
|
|
|
switch P.tok {
|
|
case Scanner.CONST, Scanner.TYPE, Scanner.VAR:
|
|
d = P.ParseDecl(P.tok);
|
|
case Scanner.FUNC:
|
|
d = P.ParseFunctionDecl();
|
|
default:
|
|
P.Error(P.pos, "declaration expected");
|
|
P.Next(); // make progress
|
|
}
|
|
|
|
return d;
|
|
}
|
|
|
|
|
|
// ----------------------------------------------------------------------------
|
|
// Program
|
|
|
|
func (P *Parser) ParseProgram() *AST.Program {
|
|
if P.verbose {
|
|
P.Trace("Program");
|
|
defer P.Ecart();
|
|
}
|
|
|
|
P.OpenScope();
|
|
p := AST.NewProgram(P.pos);
|
|
P.Expect(Scanner.PACKAGE);
|
|
p.Ident = P.ParseIdent(nil);
|
|
|
|
// package body
|
|
{ P.OpenScope();
|
|
p.Decls = array.New(0);
|
|
for P.tok == Scanner.IMPORT {
|
|
p.Decls.Push(P.ParseDecl(Scanner.IMPORT));
|
|
P.OptSemicolon();
|
|
}
|
|
if !P.deps {
|
|
for P.tok != Scanner.EOF {
|
|
p.Decls.Push(P.ParseDeclaration());
|
|
P.OptSemicolon();
|
|
}
|
|
}
|
|
P.CloseScope();
|
|
}
|
|
|
|
p.Comments = P.comments;
|
|
P.CloseScope();
|
|
|
|
return p;
|
|
}
|