mirror of
https://github.com/golang/go
synced 2024-11-25 06:47:56 -07:00
1762 lines
35 KiB
Go
1762 lines
35 KiB
Go
// Copyright 2009 The Go Authors. All rights reserved.
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// Use of this source code is governed by a BSD-style
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// license that can be found in the LICENSE file.
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package Parser
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import (
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"array";
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Scanner "scanner";
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AST "ast";
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)
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export type Parser struct {
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// Tracing/debugging
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verbose, sixg, deps, naming bool;
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indent uint;
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// Scanner
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scanner *Scanner.Scanner;
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tokchan <-chan *Scanner.Token;
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comments *array.Array;
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// Scanner.Token
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pos int; // token source position
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tok int; // one token look-ahead
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val string; // token value (for IDENT, NUMBER, STRING only)
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// Non-syntactic parser control
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opt_semi bool; // true if semicolon is optional
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// Nesting levels
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expr_lev int; // 0 = control clause level, 1 = expr inside ()'s
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scope_lev int; // 0 = global scope, 1 = function scope of global functions, etc.
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// Scopes
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top_scope *AST.Scope;
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};
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// ----------------------------------------------------------------------------
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// Elementary support
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func unimplemented() {
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panic("unimplemented");
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}
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func unreachable() {
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panic("unreachable");
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}
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func assert(pred bool) {
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if !pred {
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panic("assertion failed");
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}
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}
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// ----------------------------------------------------------------------------
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// Parsing support
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func (P *Parser) PrintIndent() {
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for i := P.indent; i > 0; i-- {
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print(". ");
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}
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}
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func (P *Parser) Trace(msg string) {
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if P.verbose {
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P.PrintIndent();
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print(msg, " {\n");
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}
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P.indent++; // always check proper identation
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}
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func (P *Parser) Ecart() {
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P.indent--; // always check proper identation
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if P.verbose {
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P.PrintIndent();
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print("}\n");
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}
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}
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func (P *Parser) Next0() {
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if P.tokchan == nil {
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P.pos, P.tok, P.val = P.scanner.Scan();
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} else {
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t := <-P.tokchan;
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P.tok, P.pos, P.val = t.Tok, t.Pos, t.Val;
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}
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P.opt_semi = false;
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if P.verbose {
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P.PrintIndent();
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print("[", P.pos, "] ", Scanner.TokenString(P.tok), "\n");
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}
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}
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func (P *Parser) Next() {
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for P.Next0(); P.tok == Scanner.COMMENT; P.Next0() {
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P.comments.Push(AST.NewComment(P.pos, P.val));
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}
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}
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func (P *Parser) Open(verbose, sixg, deps, naming bool, scanner *Scanner.Scanner, tokchan <-chan *Scanner.Token) {
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P.verbose = verbose;
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P.sixg = sixg;
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P.deps = deps;
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P.naming = naming;
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P.indent = 0;
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P.scanner = scanner;
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P.tokchan = tokchan;
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P.comments = array.New(0);
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P.Next();
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P.expr_lev = 0;
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P.scope_lev = 0;
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}
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func (P *Parser) Error(pos int, msg string) {
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P.scanner.Error(pos, msg);
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}
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func (P *Parser) Expect(tok int) {
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if P.tok != tok {
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msg := "expected '" + Scanner.TokenString(tok) + "', found '" + Scanner.TokenString(P.tok) + "'";
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switch P.tok {
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case Scanner.IDENT, Scanner.INT, Scanner.FLOAT, Scanner.STRING:
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msg += " " + P.val;
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}
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P.Error(P.pos, msg);
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}
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P.Next(); // make progress in any case
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}
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func (P *Parser) OptSemicolon() {
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if P.tok == Scanner.SEMICOLON {
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P.Next();
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}
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}
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// ----------------------------------------------------------------------------
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// Scopes
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func (P *Parser) OpenScope() {
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P.top_scope = AST.NewScope(P.top_scope);
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}
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func (P *Parser) CloseScope() {
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P.top_scope = P.top_scope.parent;
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}
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func (P *Parser) DeclareInScope(scope *AST.Scope, x *AST.Expr, kind int) {
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if P.scope_lev < 0 {
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panic("cannot declare objects in other packages");
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}
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if x.Tok != Scanner.ILLEGAL { // ignore bad exprs
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obj := x.Obj;
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assert(x.Tok == Scanner.IDENT && obj.Kind == AST.NONE);
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obj.Kind = kind;
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obj.Pnolev = P.scope_lev;
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if scope.LookupLocal(obj.Ident) != nil {
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P.Error(obj.Pos, `"` + obj.Ident + `" is declared already`);
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return; // don't insert it into the scope
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}
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scope.Insert(obj);
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}
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}
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// Declare a comma-separated list of idents or a single ident.
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func (P *Parser) Declare(p *AST.Expr, kind int) {
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for p.Tok == Scanner.COMMA {
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P.DeclareInScope(P.top_scope, p.X, kind);
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p = p.Y;
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}
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P.DeclareInScope(P.top_scope, p, kind);
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}
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func (P *Parser) VerifyExport1(p *AST.Expr, exported bool) {
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obj := p.Obj;
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if exported {
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if !obj.IsExported() {
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P.Error(obj.Pos, `"` + obj.Ident + `" should be uppercase`);
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}
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} else if P.scope_lev == 0 {
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if obj.IsExported() {
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P.Error(obj.Pos, `"` + obj.Ident + `" should be lowercase`);
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}
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}
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}
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func (P *Parser) VerifyExport(p *AST.Expr, exported bool) {
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if !P.naming {
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return;
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}
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for p.Tok == Scanner.COMMA {
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P.VerifyExport1(p.X, exported);
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p = p.Y;
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}
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P.VerifyExport1(p, exported);
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}
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// ----------------------------------------------------------------------------
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// AST support
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func exprType(x *AST.Expr) *AST.Type {
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var t *AST.Type;
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if x.Tok == Scanner.TYPE {
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t = x.Obj.Typ;
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} else if x.Tok == Scanner.IDENT {
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// assume a type name
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t = AST.NewType(x.Pos, AST.TYPENAME);
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t.Expr = x;
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} else if x.Tok == Scanner.PERIOD && x.Y != nil && exprType(x.X) != nil {
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// possibly a qualified (type) identifier
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t = AST.NewType(x.Pos, AST.TYPENAME);
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t.Expr = x;
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}
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return t;
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}
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func (P *Parser) NoType(x *AST.Expr) *AST.Expr {
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if x != nil && x.Tok == Scanner.TYPE {
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P.Error(x.Pos, "expected expression, found type");
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val := AST.NewObject(x.Pos, AST.NONE, "0");
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x = AST.NewLit(Scanner.INT, val);
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}
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return x;
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}
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func (P *Parser) NewExpr(pos, tok int, x, y *AST.Expr) *AST.Expr {
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return AST.NewExpr(pos, tok, P.NoType(x), P.NoType(y));
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}
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// ----------------------------------------------------------------------------
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// Common productions
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func (P *Parser) TryType() *AST.Type;
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func (P *Parser) ParseExpression(prec int) *AST.Expr;
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func (P *Parser) ParseStatement() *AST.Stat;
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func (P *Parser) ParseDeclaration() *AST.Decl;
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// If scope != nil, lookup identifier in scope. Otherwise create one.
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func (P *Parser) ParseIdent(scope *AST.Scope) *AST.Expr {
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P.Trace("Ident");
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x := AST.BadExpr;
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if P.tok == Scanner.IDENT {
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var obj *AST.Object;
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if scope != nil {
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obj = scope.Lookup(P.val);
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}
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if obj == nil {
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obj = AST.NewObject(P.pos, AST.NONE, P.val);
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} else {
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assert(obj.Kind != AST.NONE);
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}
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x = AST.NewLit(Scanner.IDENT, obj);
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x.Pos = P.pos; // override obj.pos (incorrect if object was looked up!)
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if P.verbose {
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P.PrintIndent();
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print("Ident = \"", P.val, "\"\n");
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}
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P.Next();
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} else {
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P.Expect(Scanner.IDENT); // use Expect() error handling
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}
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P.Ecart();
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return x;
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}
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func (P *Parser) ParseIdentList() *AST.Expr {
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P.Trace("IdentList");
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var last *AST.Expr;
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x := P.ParseIdent(nil);
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for P.tok == Scanner.COMMA {
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pos := P.pos;
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P.Next();
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y := P.ParseIdent(nil);
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if last == nil {
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x = P.NewExpr(pos, Scanner.COMMA, x, y);
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last = x;
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} else {
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last.Y = P.NewExpr(pos, Scanner.COMMA, last.Y, y);
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last = last.Y;
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}
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}
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P.Ecart();
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return x;
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}
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// ----------------------------------------------------------------------------
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// Types
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func (P *Parser) ParseType() *AST.Type {
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P.Trace("Type");
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t := P.TryType();
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if t == nil {
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P.Error(P.pos, "type expected");
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t = AST.BadType;
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}
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P.Ecart();
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return t;
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}
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func (P *Parser) ParseVarType() *AST.Type {
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P.Trace("VarType");
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typ := P.ParseType();
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P.Ecart();
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return typ;
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}
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func (P *Parser) ParseQualifiedIdent() *AST.Expr {
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P.Trace("QualifiedIdent");
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x := P.ParseIdent(P.top_scope);
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for P.tok == Scanner.PERIOD {
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pos := P.pos;
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P.Next();
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y := P.ParseIdent(nil);
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x = P.NewExpr(pos, Scanner.PERIOD, x, y);
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}
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P.Ecart();
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return x;
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}
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func (P *Parser) ParseTypeName() *AST.Type {
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P.Trace("TypeName");
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t := AST.NewType(P.pos, AST.TYPENAME);
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t.Expr = P.ParseQualifiedIdent();
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P.Ecart();
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return t;
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}
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func (P *Parser) ParseArrayType() *AST.Type {
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P.Trace("ArrayType");
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t := AST.NewType(P.pos, AST.ARRAY);
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P.Expect(Scanner.LBRACK);
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if P.tok == Scanner.ELLIPSIS {
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t.Expr = P.NewExpr(P.pos, Scanner.ELLIPSIS, nil, nil);
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P.Next();
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} else if P.tok != Scanner.RBRACK {
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t.Expr = P.ParseExpression(1);
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}
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P.Expect(Scanner.RBRACK);
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t.Elt = P.ParseType();
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P.Ecart();
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return t;
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}
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func (P *Parser) ParseChannelType() *AST.Type {
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P.Trace("ChannelType");
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t := AST.NewType(P.pos, AST.CHANNEL);
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t.Mode = AST.FULL;
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if P.tok == Scanner.CHAN {
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P.Next();
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if P.tok == Scanner.ARROW {
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P.Next();
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t.Mode = AST.SEND;
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}
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} else {
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P.Expect(Scanner.ARROW);
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P.Expect(Scanner.CHAN);
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t.Mode = AST.RECV;
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}
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t.Elt = P.ParseVarType();
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P.Ecart();
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return t;
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}
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func (P *Parser) ParseVar(expect_ident bool) *AST.Type {
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t := AST.BadType;
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if expect_ident {
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x := P.ParseIdent(nil);
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t = AST.NewType(x.Pos, AST.TYPENAME);
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t.Expr = x;
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} else if P.tok == Scanner.ELLIPSIS {
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t = AST.NewType(P.pos, AST.ELLIPSIS);
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P.Next();
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} else {
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t = P.ParseType();
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}
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return t;
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}
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func (P *Parser) ParseVarList(list *array.Array, ellipsis_ok bool) {
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P.Trace("VarList");
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// assume a list of types
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// (a list of identifiers looks like a list of type names)
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i0 := list.Len();
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for {
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list.Push(P.ParseVar(ellipsis_ok /* param list */ && i0 > 0));
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if P.tok == Scanner.COMMA {
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P.Next();
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} else {
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break;
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}
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}
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// if we had a list of identifiers, it must be followed by a type
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typ := P.TryType();
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if typ == nil && P.tok == Scanner.ELLIPSIS {
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typ = AST.NewType(P.pos, AST.ELLIPSIS);
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P.Next();
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}
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if ellipsis_ok /* param list */ && i0 > 0 && typ == nil {
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// not the first parameter section; we must have a type
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P.Error(P.pos, "type expected");
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typ = AST.BadType;
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}
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// convert the list into a list of (type) expressions
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if typ != nil {
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// all list entries must be identifiers
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// convert the type entries into identifiers
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for i, n := i0, list.Len(); i < n; i++ {
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t := list.At(i).(*AST.Type);
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if t.Form == AST.TYPENAME && t.Expr.Tok == Scanner.IDENT {
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list.Set(i, t.Expr);
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} else {
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list.Set(i, AST.BadExpr);
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P.Error(t.Pos, "identifier expected");
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}
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}
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// add type
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list.Push(AST.NewTypeExpr(typ));
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} else {
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// all list entries are types
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// convert all type entries into type expressions
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for i, n := i0, list.Len(); i < n; i++ {
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t := list.At(i).(*AST.Type);
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list.Set(i, AST.NewTypeExpr(t));
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}
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}
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P.Ecart();
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}
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func (P *Parser) ParseParameterList(ellipsis_ok bool) *array.Array {
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P.Trace("ParameterList");
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list := array.New(0);
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P.ParseVarList(list, ellipsis_ok);
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for P.tok == Scanner.COMMA {
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P.Next();
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P.ParseVarList(list, ellipsis_ok);
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}
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P.Ecart();
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return list;
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}
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func (P *Parser) ParseParameters(ellipsis_ok bool) *AST.Type {
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P.Trace("Parameters");
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t := AST.NewType(P.pos, AST.STRUCT);
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P.Expect(Scanner.LPAREN);
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if P.tok != Scanner.RPAREN {
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t.List = P.ParseParameterList(ellipsis_ok);
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}
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t.End = P.pos;
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P.Expect(Scanner.RPAREN);
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P.Ecart();
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return t;
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}
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func (P *Parser) ParseResultList() {
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P.Trace("ResultList");
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P.ParseType();
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for P.tok == Scanner.COMMA {
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P.Next();
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P.ParseType();
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}
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if P.tok != Scanner.RPAREN {
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P.ParseType();
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}
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P.Ecart();
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}
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func (P *Parser) ParseResult() *AST.Type {
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P.Trace("Result");
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var t *AST.Type;
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if P.tok == Scanner.LPAREN {
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t = P.ParseParameters(false);
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} else {
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typ := P.TryType();
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if typ != nil {
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t = AST.NewType(P.pos, AST.STRUCT);
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t.List = array.New(0);
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t.List.Push(AST.NewTypeExpr(typ));
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t.End = P.pos;
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}
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}
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P.Ecart();
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return t;
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}
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// Function types
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//
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// (params)
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// (params) type
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// (params) (results)
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func (P *Parser) ParseFunctionType() *AST.Type {
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P.Trace("FunctionType");
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P.OpenScope();
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P.scope_lev++;
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t := AST.NewType(P.pos, AST.FUNCTION);
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t.List = P.ParseParameters(true).List; // TODO find better solution
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t.End = P.pos;
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t.Elt = P.ParseResult();
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P.scope_lev--;
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P.CloseScope();
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P.Ecart();
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return t;
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}
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func (P *Parser) ParseMethodSpec(list *array.Array) {
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P.Trace("MethodDecl");
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list.Push(P.ParseIdentList());
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t := AST.BadType;
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if P.sixg {
|
|
t = P.ParseType();
|
|
} else {
|
|
t = P.ParseFunctionType();
|
|
}
|
|
list.Push(AST.NewTypeExpr(t));
|
|
|
|
P.Ecart();
|
|
}
|
|
|
|
|
|
func (P *Parser) ParseInterfaceType() *AST.Type {
|
|
P.Trace("InterfaceType");
|
|
|
|
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);
|
|
}
|
|
|
|
P.Ecart();
|
|
return t;
|
|
}
|
|
|
|
|
|
func (P *Parser) ParseMapType() *AST.Type {
|
|
P.Trace("MapType");
|
|
|
|
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();
|
|
|
|
P.Ecart();
|
|
return t;
|
|
}
|
|
|
|
|
|
func (P *Parser) ParseOperand() *AST.Expr
|
|
|
|
func (P *Parser) ParseStructType() *AST.Type {
|
|
P.Trace("StructType");
|
|
|
|
t := AST.NewType(P.pos, AST.STRUCT);
|
|
P.Expect(Scanner.STRUCT);
|
|
if P.tok == Scanner.LBRACE {
|
|
P.Next();
|
|
P.OpenScope();
|
|
P.scope_lev++;
|
|
|
|
t.List = array.New(0);
|
|
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.scope_lev--;
|
|
P.CloseScope();
|
|
P.Expect(Scanner.RBRACE);
|
|
}
|
|
|
|
P.Ecart();
|
|
return t;
|
|
}
|
|
|
|
|
|
func (P *Parser) ParsePointerType() *AST.Type {
|
|
P.Trace("PointerType");
|
|
|
|
t := AST.NewType(P.pos, AST.POINTER);
|
|
P.Expect(Scanner.MUL);
|
|
t.Elt = P.ParseType();
|
|
|
|
P.Ecart();
|
|
return t;
|
|
}
|
|
|
|
|
|
func (P *Parser) TryType() *AST.Type {
|
|
P.Trace("Type (try)");
|
|
|
|
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.LPAREN: 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
|
|
}
|
|
|
|
P.Ecart();
|
|
return t;
|
|
}
|
|
|
|
|
|
// ----------------------------------------------------------------------------
|
|
// Blocks
|
|
|
|
func (P *Parser) ParseStatementList() *array.Array {
|
|
P.Trace("StatementList");
|
|
|
|
list := array.New(0);
|
|
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?)");
|
|
}
|
|
|
|
P.Ecart();
|
|
return list;
|
|
}
|
|
|
|
|
|
func (P *Parser) ParseBlock() (slist *array.Array, end int) {
|
|
P.Trace("Block");
|
|
|
|
P.Expect(Scanner.LBRACE);
|
|
P.OpenScope();
|
|
|
|
slist = P.ParseStatementList();
|
|
end = P.pos;
|
|
|
|
P.CloseScope();
|
|
P.Expect(Scanner.RBRACE);
|
|
P.opt_semi = true;
|
|
|
|
P.Ecart();
|
|
return slist, end;
|
|
}
|
|
|
|
|
|
// ----------------------------------------------------------------------------
|
|
// Expressions
|
|
|
|
func (P *Parser) ParseExpressionList() *AST.Expr {
|
|
P.Trace("ExpressionList");
|
|
|
|
x := P.ParseExpression(1);
|
|
for first := true; P.tok == Scanner.COMMA; {
|
|
pos := P.pos;
|
|
P.Next();
|
|
y := P.ParseExpression(1);
|
|
if first {
|
|
x = P.NewExpr(pos, Scanner.COMMA, x, y);
|
|
first = false;
|
|
} else {
|
|
x.Y = P.NewExpr(pos, Scanner.COMMA, x.Y, y);
|
|
}
|
|
}
|
|
|
|
P.Ecart();
|
|
return x;
|
|
}
|
|
|
|
|
|
func (P *Parser) ParseFunctionLit() *AST.Expr {
|
|
P.Trace("FunctionLit");
|
|
|
|
val := AST.NewObject(P.pos, AST.NONE, "");
|
|
x := AST.NewLit(Scanner.FUNC, val);
|
|
P.Expect(Scanner.FUNC);
|
|
val.Typ = P.ParseFunctionType();
|
|
P.expr_lev++;
|
|
P.scope_lev++;
|
|
val.Block, val.End = P.ParseBlock();
|
|
P.scope_lev--;
|
|
P.expr_lev--;
|
|
|
|
P.Ecart();
|
|
return x;
|
|
}
|
|
|
|
|
|
/*
|
|
func (P *Parser) ParseNewCall() *AST.Expr {
|
|
P.Trace("NewCall");
|
|
|
|
x := AST.NewExpr(P.pos, Scanner.NEW, nil, nil);
|
|
P.Next();
|
|
P.Expect(Scanner.LPAREN);
|
|
P.expr_lev++;
|
|
x.t = P.ParseType();
|
|
if P.tok == Scanner.COMMA {
|
|
P.Next();
|
|
x.Y = P.ParseExpressionList();
|
|
}
|
|
P.expr_lev--;
|
|
P.Expect(Scanner.RPAREN);
|
|
|
|
P.Ecart();
|
|
return x;
|
|
}
|
|
*/
|
|
|
|
|
|
func (P *Parser) ParseOperand() *AST.Expr {
|
|
P.Trace("Operand");
|
|
|
|
x := AST.BadExpr;
|
|
switch P.tok {
|
|
case Scanner.IDENT:
|
|
x = 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);
|
|
|
|
case Scanner.INT, Scanner.FLOAT, Scanner.STRING:
|
|
val := AST.NewObject(P.pos, AST.NONE, P.val);
|
|
x = AST.NewLit(P.tok, 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.Obj.Ident += P.val;
|
|
}
|
|
}
|
|
|
|
case Scanner.FUNC:
|
|
x = P.ParseFunctionLit();
|
|
|
|
default:
|
|
t := P.TryType();
|
|
if t != nil {
|
|
x = AST.NewTypeExpr(t);
|
|
} else {
|
|
P.Error(P.pos, "operand expected");
|
|
P.Next(); // make progress
|
|
}
|
|
}
|
|
|
|
P.Ecart();
|
|
return x;
|
|
}
|
|
|
|
|
|
func (P *Parser) ParseSelectorOrTypeGuard(x *AST.Expr) *AST.Expr {
|
|
P.Trace("SelectorOrTypeGuard");
|
|
|
|
x = P.NewExpr(P.pos, Scanner.PERIOD, x, nil);
|
|
P.Expect(Scanner.PERIOD);
|
|
|
|
if P.tok == Scanner.IDENT {
|
|
x.Y = P.ParseIdent(nil);
|
|
|
|
} else {
|
|
P.Expect(Scanner.LPAREN);
|
|
x.Y = AST.NewTypeExpr(P.ParseType());
|
|
P.Expect(Scanner.RPAREN);
|
|
}
|
|
|
|
P.Ecart();
|
|
return x;
|
|
}
|
|
|
|
|
|
func (P *Parser) ParseIndex(x *AST.Expr) *AST.Expr {
|
|
P.Trace("IndexOrSlice");
|
|
|
|
pos := P.pos;
|
|
P.Expect(Scanner.LBRACK);
|
|
P.expr_lev++;
|
|
i := P.ParseExpression(0);
|
|
P.expr_lev--;
|
|
P.Expect(Scanner.RBRACK);
|
|
|
|
P.Ecart();
|
|
return P.NewExpr(pos, Scanner.LBRACK, x, i);
|
|
}
|
|
|
|
|
|
func (P *Parser) ParseBinaryExpr(prec1 int) *AST.Expr
|
|
|
|
func (P *Parser) ParseCall(x0 *AST.Expr) *AST.Expr {
|
|
P.Trace("Call");
|
|
|
|
x := P.NewExpr(P.pos, Scanner.LPAREN, x0, nil);
|
|
P.Expect(Scanner.LPAREN);
|
|
if P.tok != Scanner.RPAREN {
|
|
P.expr_lev++;
|
|
var t *AST.Type;
|
|
if x0.Tok == Scanner.IDENT && (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
|
|
x.Y = AST.NewTypeExpr(t);
|
|
if P.tok == Scanner.COMMA {
|
|
pos := P.pos;
|
|
P.Next();
|
|
y := P.ParseExpressionList();
|
|
// create list manually because NewExpr checks for type expressions
|
|
z := AST.NewExpr(pos, Scanner.COMMA, nil, y);
|
|
z.X = x.Y;
|
|
x.Y = z;
|
|
}
|
|
} else {
|
|
// normal argument list
|
|
x.Y = P.ParseExpressionList();
|
|
}
|
|
P.expr_lev--;
|
|
}
|
|
P.Expect(Scanner.RPAREN);
|
|
|
|
P.Ecart();
|
|
return x;
|
|
}
|
|
|
|
|
|
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 x.Tok == Scanner.COLON {
|
|
singles = false;
|
|
}
|
|
|
|
var last *AST.Expr;
|
|
for P.tok != Scanner.RBRACE && P.tok != Scanner.EOF {
|
|
y := P.ParseExpression(0);
|
|
|
|
if singles {
|
|
if y.Tok == Scanner.COLON {
|
|
P.Error(y.X.Pos, "single value expected; found pair");
|
|
}
|
|
} else {
|
|
if y.Tok != Scanner.COLON {
|
|
P.Error(y.Pos, "key:value pair expected; found single value");
|
|
}
|
|
}
|
|
|
|
if last == nil {
|
|
x = P.NewExpr(pos, Scanner.COMMA, x, y);
|
|
last = x;
|
|
} else {
|
|
last.Y = P.NewExpr(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 {
|
|
P.Trace("CompositeLit");
|
|
|
|
x := P.NewExpr(P.pos, Scanner.LBRACE, nil, nil);
|
|
x.Obj = AST.NewObject(t.Pos, AST.TYPE, "");
|
|
x.Obj.Typ = t;
|
|
P.Expect(Scanner.LBRACE);
|
|
if P.tok != Scanner.RBRACE {
|
|
x.Y = P.ParseCompositeElements();
|
|
}
|
|
P.Expect(Scanner.RBRACE);
|
|
|
|
P.Ecart();
|
|
return x;
|
|
}
|
|
|
|
|
|
func (P *Parser) ParsePrimaryExpr() *AST.Expr {
|
|
P.Trace("PrimaryExpr");
|
|
|
|
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 {
|
|
goto exit;
|
|
}
|
|
default: goto exit;
|
|
}
|
|
}
|
|
|
|
exit:
|
|
P.Ecart();
|
|
return x;
|
|
}
|
|
|
|
|
|
func (P *Parser) ParseUnaryExpr() *AST.Expr {
|
|
P.Trace("UnaryExpr");
|
|
|
|
x := AST.BadExpr;
|
|
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 tok == Scanner.MUL && y.Tok == Scanner.TYPE {
|
|
// pointer type
|
|
t := AST.NewType(pos, AST.POINTER);
|
|
t.Elt = y.Obj.Typ;
|
|
x = AST.NewTypeExpr(t);
|
|
} else {
|
|
x = P.NewExpr(pos, tok, nil, y);
|
|
}
|
|
|
|
default:
|
|
x = P.ParsePrimaryExpr();
|
|
}
|
|
|
|
P.Ecart();
|
|
return x;
|
|
}
|
|
|
|
|
|
func (P *Parser) ParseBinaryExpr(prec1 int) *AST.Expr {
|
|
P.Trace("BinaryExpr");
|
|
|
|
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.NewExpr(pos, tok, x, y);
|
|
}
|
|
}
|
|
|
|
P.Ecart();
|
|
return x;
|
|
}
|
|
|
|
|
|
func (P *Parser) ParseExpression(prec int) *AST.Expr {
|
|
P.Trace("Expression");
|
|
indent := P.indent;
|
|
|
|
if prec < 0 {
|
|
panic("precedence must be >= 0");
|
|
}
|
|
x := P.NoType(P.ParseBinaryExpr(prec));
|
|
|
|
if indent != P.indent {
|
|
panic("imbalanced tracing code (Expression)");
|
|
}
|
|
P.Ecart();
|
|
return x;
|
|
}
|
|
|
|
|
|
// ----------------------------------------------------------------------------
|
|
// Statements
|
|
|
|
func (P *Parser) ParseSimpleStat(range_ok bool) *AST.Stat {
|
|
P.Trace("SimpleStat");
|
|
|
|
s := AST.BadStat;
|
|
x := P.ParseExpressionList();
|
|
|
|
is_range := false;
|
|
if range_ok && P.tok == Scanner.COLON {
|
|
pos := P.pos;
|
|
P.Next();
|
|
y := P.ParseExpression(1);
|
|
if x.Len() == 1 {
|
|
x = P.NewExpr(pos, Scanner.COLON, x, y);
|
|
is_range = true;
|
|
} else {
|
|
P.Error(pos, "expected initialization, found ':'");
|
|
}
|
|
}
|
|
|
|
switch P.tok {
|
|
case Scanner.COLON:
|
|
// label declaration
|
|
s = AST.NewStat(P.pos, Scanner.COLON);
|
|
s.Expr = x;
|
|
if x.Len() != 1 {
|
|
P.Error(x.Pos, "illegal label declaration");
|
|
}
|
|
P.Next(); // consume ":"
|
|
P.opt_semi = true;
|
|
|
|
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();
|
|
y := AST.BadExpr;
|
|
if P.tok == Scanner.RANGE {
|
|
range_pos := P.pos;
|
|
P.Next();
|
|
y = P.ParseExpression(1);
|
|
y = P.NewExpr(range_pos, Scanner.RANGE, nil, y);
|
|
if tok != Scanner.DEFINE && tok != Scanner.ASSIGN {
|
|
P.Error(pos, "expected '=' or ':=', found '" + Scanner.TokenString(tok) + "'");
|
|
}
|
|
} else {
|
|
y = P.ParseExpressionList();
|
|
if is_range {
|
|
P.Error(y.Pos, "expected 'range', found expression");
|
|
}
|
|
if xl, yl := x.Len(), y.Len(); xl > 1 && yl > 1 && xl != yl {
|
|
P.Error(x.Pos, "arity of lhs doesn't match rhs");
|
|
}
|
|
}
|
|
s = AST.NewStat(x.Pos, Scanner.EXPRSTAT);
|
|
s.Expr = AST.NewExpr(pos, tok, x, y);
|
|
|
|
case Scanner.RANGE:
|
|
pos := P.pos;
|
|
P.Next();
|
|
y := P.ParseExpression(1);
|
|
y = P.NewExpr(pos, Scanner.RANGE, nil, y);
|
|
s = AST.NewStat(x.Pos, Scanner.EXPRSTAT);
|
|
s.Expr = AST.NewExpr(pos, Scanner.DEFINE, x, y);
|
|
|
|
default:
|
|
var pos, tok int;
|
|
if P.tok == Scanner.INC || P.tok == Scanner.DEC {
|
|
pos, tok = P.pos, P.tok;
|
|
P.Next();
|
|
} else {
|
|
pos, tok = x.Pos, Scanner.EXPRSTAT;
|
|
}
|
|
s = AST.NewStat(pos, tok);
|
|
s.Expr = x;
|
|
if x.Len() != 1 {
|
|
P.Error(x.Pos, "only one expression allowed");
|
|
}
|
|
}
|
|
|
|
P.Ecart();
|
|
return s;
|
|
}
|
|
|
|
|
|
func (P *Parser) ParseGoStat() *AST.Stat {
|
|
P.Trace("GoStat");
|
|
|
|
s := AST.NewStat(P.pos, Scanner.GO);
|
|
P.Expect(Scanner.GO);
|
|
s.Expr = P.ParseExpression(1);
|
|
|
|
P.Ecart();
|
|
return s;
|
|
}
|
|
|
|
|
|
func (P *Parser) ParseReturnStat() *AST.Stat {
|
|
P.Trace("ReturnStat");
|
|
|
|
s := AST.NewStat(P.pos, Scanner.RETURN);
|
|
P.Expect(Scanner.RETURN);
|
|
if P.tok != Scanner.SEMICOLON && P.tok != Scanner.RBRACE {
|
|
s.Expr = P.ParseExpressionList();
|
|
}
|
|
|
|
P.Ecart();
|
|
return s;
|
|
}
|
|
|
|
|
|
func (P *Parser) ParseControlFlowStat(tok int) *AST.Stat {
|
|
P.Trace("ControlFlowStat");
|
|
|
|
s := AST.NewStat(P.pos, tok);
|
|
P.Expect(tok);
|
|
if tok != Scanner.FALLTHROUGH && P.tok == Scanner.IDENT {
|
|
s.Expr = P.ParseIdent(P.top_scope);
|
|
}
|
|
|
|
P.Ecart();
|
|
return s;
|
|
}
|
|
|
|
|
|
func (P *Parser) ParseControlClause(keyword int) *AST.Stat {
|
|
P.Trace("ControlClause");
|
|
|
|
s := AST.NewStat(P.pos, keyword);
|
|
P.Expect(keyword);
|
|
if P.tok != Scanner.LBRACE {
|
|
prev_lev := P.expr_lev;
|
|
P.expr_lev = -1;
|
|
if P.tok != Scanner.SEMICOLON {
|
|
s.Init = P.ParseSimpleStat(keyword == Scanner.FOR);
|
|
// 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 {
|
|
s.Expr = P.ParseExpression(1);
|
|
}
|
|
if keyword == Scanner.FOR {
|
|
P.Expect(Scanner.SEMICOLON);
|
|
if P.tok != Scanner.LBRACE {
|
|
s.Post = P.ParseSimpleStat(false);
|
|
}
|
|
}
|
|
} else {
|
|
if s.Init != nil { // guard in case of errors
|
|
s.Expr, s.Init = s.Init.Expr, nil;
|
|
}
|
|
}
|
|
P.expr_lev = prev_lev;
|
|
}
|
|
|
|
P.Ecart();
|
|
return s;
|
|
}
|
|
|
|
|
|
func (P *Parser) ParseIfStat() *AST.Stat {
|
|
P.Trace("IfStat");
|
|
|
|
P.OpenScope();
|
|
s := P.ParseControlClause(Scanner.IF);
|
|
s.Block, s.End = P.ParseBlock();
|
|
if P.tok == Scanner.ELSE {
|
|
P.Next();
|
|
s1 := AST.BadStat;
|
|
if P.tok == Scanner.IF {
|
|
s1 = P.ParseIfStat();
|
|
} else if P.sixg {
|
|
s1 = P.ParseStatement();
|
|
if s1 != nil {
|
|
// not the empty statement
|
|
if s1.Tok != Scanner.LBRACE {
|
|
// wrap in a block if we don't have one
|
|
b := AST.NewStat(P.pos, Scanner.LBRACE);
|
|
b.Block = array.New(0);
|
|
b.Block.Push(s1);
|
|
s1 = b;
|
|
}
|
|
s.Post = s1;
|
|
}
|
|
} else {
|
|
s1 = AST.NewStat(P.pos, Scanner.LBRACE);
|
|
s1.Block, s1.End = P.ParseBlock();
|
|
}
|
|
s.Post = s1;
|
|
}
|
|
P.CloseScope();
|
|
|
|
P.Ecart();
|
|
return s;
|
|
}
|
|
|
|
|
|
func (P *Parser) ParseForStat() *AST.Stat {
|
|
P.Trace("ForStat");
|
|
|
|
P.OpenScope();
|
|
s := P.ParseControlClause(Scanner.FOR);
|
|
s.Block, s.End = P.ParseBlock();
|
|
P.CloseScope();
|
|
|
|
P.Ecart();
|
|
return s;
|
|
}
|
|
|
|
|
|
func (P *Parser) ParseCase() *AST.Stat {
|
|
P.Trace("Case");
|
|
|
|
s := AST.NewStat(P.pos, P.tok);
|
|
if P.tok == Scanner.CASE {
|
|
P.Next();
|
|
s.Expr = P.ParseExpressionList();
|
|
} else {
|
|
P.Expect(Scanner.DEFAULT);
|
|
}
|
|
P.Expect(Scanner.COLON);
|
|
|
|
P.Ecart();
|
|
return s;
|
|
}
|
|
|
|
|
|
func (P *Parser) ParseCaseClause() *AST.Stat {
|
|
P.Trace("CaseClause");
|
|
|
|
s := P.ParseCase();
|
|
if P.tok != Scanner.CASE && P.tok != Scanner.DEFAULT && P.tok != Scanner.RBRACE {
|
|
s.Block = P.ParseStatementList();
|
|
}
|
|
|
|
P.Ecart();
|
|
return s;
|
|
}
|
|
|
|
|
|
func (P *Parser) ParseSwitchStat() *AST.Stat {
|
|
P.Trace("SwitchStat");
|
|
|
|
P.OpenScope();
|
|
s := P.ParseControlClause(Scanner.SWITCH);
|
|
s.Block = array.New(0);
|
|
P.Expect(Scanner.LBRACE);
|
|
for P.tok != Scanner.RBRACE && P.tok != Scanner.EOF {
|
|
s.Block.Push(P.ParseCaseClause());
|
|
}
|
|
s.End = P.pos;
|
|
P.Expect(Scanner.RBRACE);
|
|
P.opt_semi = true;
|
|
P.CloseScope();
|
|
|
|
P.Ecart();
|
|
return s;
|
|
}
|
|
|
|
|
|
func (P *Parser) ParseCommCase() *AST.Stat {
|
|
P.Trace("CommCase");
|
|
|
|
s := AST.NewStat(P.pos, P.tok);
|
|
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 = AST.NewExpr(pos, tok, x, y);
|
|
} else {
|
|
P.Expect(Scanner.ARROW); // use Expect() error handling
|
|
}
|
|
}
|
|
s.Expr = x;
|
|
} else {
|
|
P.Expect(Scanner.DEFAULT);
|
|
}
|
|
P.Expect(Scanner.COLON);
|
|
|
|
P.Ecart();
|
|
return s;
|
|
}
|
|
|
|
|
|
func (P *Parser) ParseCommClause() *AST.Stat {
|
|
P.Trace("CommClause");
|
|
|
|
s := P.ParseCommCase();
|
|
if P.tok != Scanner.CASE && P.tok != Scanner.DEFAULT && P.tok != Scanner.RBRACE {
|
|
s.Block = P.ParseStatementList();
|
|
}
|
|
|
|
P.Ecart();
|
|
return s;
|
|
}
|
|
|
|
|
|
func (P *Parser) ParseSelectStat() *AST.Stat {
|
|
P.Trace("SelectStat");
|
|
|
|
s := AST.NewStat(P.pos, Scanner.SELECT);
|
|
s.Block = array.New(0);
|
|
P.Expect(Scanner.SELECT);
|
|
P.Expect(Scanner.LBRACE);
|
|
for P.tok != Scanner.RBRACE && P.tok != Scanner.EOF {
|
|
s.Block.Push(P.ParseCommClause());
|
|
}
|
|
P.Expect(Scanner.RBRACE);
|
|
P.opt_semi = true;
|
|
|
|
P.Ecart();
|
|
return s;
|
|
}
|
|
|
|
|
|
func (P *Parser) ParseRangeStat() *AST.Stat {
|
|
P.Trace("RangeStat");
|
|
|
|
s := AST.NewStat(P.pos, Scanner.RANGE);
|
|
P.Expect(Scanner.RANGE);
|
|
P.ParseIdentList();
|
|
P.Expect(Scanner.DEFINE);
|
|
s.Expr = P.ParseExpression(1);
|
|
s.Block, s.End = P.ParseBlock();
|
|
|
|
P.Ecart();
|
|
return s;
|
|
}
|
|
|
|
|
|
func (P *Parser) ParseStatement() *AST.Stat {
|
|
P.Trace("Statement");
|
|
indent := P.indent;
|
|
|
|
s := AST.BadStat;
|
|
switch P.tok {
|
|
case Scanner.CONST, Scanner.TYPE, Scanner.VAR:
|
|
s = AST.NewStat(P.pos, P.tok);
|
|
s.Decl = 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
|
|
s = P.ParseSimpleStat(false);
|
|
case Scanner.GO:
|
|
s = P.ParseGoStat();
|
|
case Scanner.RETURN:
|
|
s = P.ParseReturnStat();
|
|
case Scanner.BREAK, Scanner.CONTINUE, Scanner.GOTO, Scanner.FALLTHROUGH:
|
|
s = P.ParseControlFlowStat(P.tok);
|
|
case Scanner.LBRACE:
|
|
s = AST.NewStat(P.pos, Scanner.LBRACE);
|
|
s.Block, s.End = P.ParseBlock();
|
|
case Scanner.IF:
|
|
s = P.ParseIfStat();
|
|
case Scanner.FOR:
|
|
s = P.ParseForStat();
|
|
case Scanner.SWITCH:
|
|
s = P.ParseSwitchStat();
|
|
case Scanner.RANGE:
|
|
s = P.ParseRangeStat();
|
|
case Scanner.SELECT:
|
|
s = P.ParseSelectStat();
|
|
default:
|
|
// empty statement
|
|
s = nil;
|
|
}
|
|
|
|
if indent != P.indent {
|
|
panic("imbalanced tracing code (Statement)");
|
|
}
|
|
P.Ecart();
|
|
return s;
|
|
}
|
|
|
|
|
|
// ----------------------------------------------------------------------------
|
|
// Declarations
|
|
|
|
func (P *Parser) ParseImportSpec(pos int) *AST.Decl {
|
|
P.Trace("ImportSpec");
|
|
|
|
d := AST.NewDecl(pos, Scanner.IMPORT, false);
|
|
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
|
|
val := AST.NewObject(P.pos, AST.NONE, P.val);
|
|
d.Val = AST.NewLit(Scanner.STRING, val);
|
|
P.Next();
|
|
} else {
|
|
P.Expect(Scanner.STRING); // use Expect() error handling
|
|
}
|
|
|
|
if d.Ident != nil {
|
|
P.Declare(d.Ident, AST.PACKAGE);
|
|
}
|
|
|
|
P.Ecart();
|
|
return d;
|
|
}
|
|
|
|
|
|
func (P *Parser) ParseConstSpec(exported bool, pos int) *AST.Decl {
|
|
P.Trace("ConstSpec");
|
|
|
|
d := AST.NewDecl(pos, Scanner.CONST, exported);
|
|
d.Ident = P.ParseIdentList();
|
|
d.Typ = P.TryType();
|
|
if P.tok == Scanner.ASSIGN {
|
|
P.Next();
|
|
d.Val = P.ParseExpressionList();
|
|
}
|
|
|
|
P.Declare(d.Ident, AST.CONST);
|
|
P.VerifyExport(d.Ident, exported);
|
|
|
|
P.Ecart();
|
|
return d;
|
|
}
|
|
|
|
|
|
func (P *Parser) ParseTypeSpec(exported bool, pos int) *AST.Decl {
|
|
P.Trace("TypeSpec");
|
|
|
|
d := AST.NewDecl(pos, Scanner.TYPE, exported);
|
|
d.Ident = P.ParseIdent(nil);
|
|
d.Typ = P.ParseType();
|
|
P.opt_semi = true;
|
|
|
|
P.VerifyExport(d.Ident, exported);
|
|
|
|
P.Ecart();
|
|
return d;
|
|
}
|
|
|
|
|
|
func (P *Parser) ParseVarSpec(exported bool, pos int) *AST.Decl {
|
|
P.Trace("VarSpec");
|
|
|
|
d := AST.NewDecl(pos, Scanner.VAR, exported);
|
|
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();
|
|
}
|
|
}
|
|
|
|
P.Declare(d.Ident, AST.VAR);
|
|
P.VerifyExport(d.Ident, exported);
|
|
|
|
P.Ecart();
|
|
return d;
|
|
}
|
|
|
|
|
|
// TODO replace this by using function pointers derived from methods
|
|
func (P *Parser) ParseSpec(exported bool, pos int, keyword int) *AST.Decl {
|
|
switch keyword {
|
|
case Scanner.IMPORT: return P.ParseImportSpec(pos);
|
|
case Scanner.CONST: return P.ParseConstSpec(exported, pos);
|
|
case Scanner.TYPE: return P.ParseTypeSpec(exported, pos);
|
|
case Scanner.VAR: return P.ParseVarSpec(exported, pos);
|
|
}
|
|
panic("UNREACHABLE");
|
|
return nil;
|
|
}
|
|
|
|
|
|
func (P *Parser) ParseDecl(exported bool, keyword int) *AST.Decl {
|
|
P.Trace("Decl");
|
|
|
|
d := AST.BadDecl;
|
|
pos := P.pos;
|
|
P.Expect(keyword);
|
|
if P.tok == Scanner.LPAREN {
|
|
P.Next();
|
|
d = AST.NewDecl(pos, keyword, exported);
|
|
d.List = array.New(0);
|
|
for P.tok != Scanner.RPAREN && P.tok != Scanner.EOF {
|
|
d.List.Push(P.ParseSpec(exported, pos, keyword));
|
|
if P.tok == Scanner.SEMICOLON {
|
|
P.Next();
|
|
} else {
|
|
break;
|
|
}
|
|
}
|
|
d.End = P.pos;
|
|
P.Expect(Scanner.RPAREN);
|
|
P.opt_semi = true;
|
|
|
|
} else {
|
|
d = P.ParseSpec(exported, pos, keyword);
|
|
}
|
|
|
|
P.Ecart();
|
|
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(exported bool) *AST.Decl {
|
|
P.Trace("FunctionDecl");
|
|
|
|
d := AST.NewDecl(P.pos, Scanner.FUNC, exported);
|
|
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");
|
|
}
|
|
}
|
|
|
|
d.Ident = P.ParseIdent(nil);
|
|
d.Typ = P.ParseFunctionType();
|
|
d.Typ.Key = recv;
|
|
|
|
if P.tok == Scanner.LBRACE {
|
|
P.scope_lev++;
|
|
d.List, d.End = P.ParseBlock();
|
|
P.scope_lev--;
|
|
}
|
|
|
|
if recv == nil || exported {
|
|
P.VerifyExport(d.Ident, exported);
|
|
}
|
|
|
|
P.Ecart();
|
|
return d;
|
|
}
|
|
|
|
|
|
func (P *Parser) ParseExportDecl() *AST.Decl {
|
|
P.Trace("ExportDecl");
|
|
|
|
d := AST.NewDecl(P.pos, Scanner.EXPORT, false);
|
|
d.Ident = P.ParseIdentList();
|
|
|
|
P.Ecart();
|
|
return d;
|
|
}
|
|
|
|
|
|
func (P *Parser) ParseDeclaration() *AST.Decl {
|
|
P.Trace("Declaration");
|
|
indent := P.indent;
|
|
|
|
d := AST.BadDecl;
|
|
exported := false;
|
|
// TODO don't use bool flag for export
|
|
if P.tok == Scanner.EXPORT || P.tok == Scanner.PACKAGE {
|
|
if P.scope_lev == 0 {
|
|
exported = true;
|
|
} else {
|
|
P.Error(P.pos, "local declarations cannot be exported");
|
|
}
|
|
P.Next();
|
|
}
|
|
|
|
switch P.tok {
|
|
case Scanner.CONST, Scanner.TYPE, Scanner.VAR:
|
|
d = P.ParseDecl(exported, P.tok);
|
|
case Scanner.FUNC:
|
|
d = P.ParseFunctionDecl(exported);
|
|
case Scanner.EXPORT:
|
|
if exported {
|
|
P.Error(P.pos, "cannot mark export declaration for export");
|
|
}
|
|
P.Next();
|
|
d = P.ParseExportDecl();
|
|
default:
|
|
if exported && (P.tok == Scanner.IDENT || P.tok == Scanner.LPAREN) {
|
|
d = P.ParseExportDecl();
|
|
} else {
|
|
P.Error(P.pos, "declaration expected");
|
|
P.Next(); // make progress
|
|
}
|
|
}
|
|
|
|
if indent != P.indent {
|
|
panic("imbalanced tracing code (Declaration)");
|
|
}
|
|
P.Ecart();
|
|
return d;
|
|
}
|
|
|
|
|
|
// ----------------------------------------------------------------------------
|
|
// Program
|
|
|
|
func (P *Parser) ParseProgram() *AST.Program {
|
|
P.Trace("Program");
|
|
|
|
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(false, 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();
|
|
|
|
P.Ecart();
|
|
return p;
|
|
}
|