- added missing file

R=r
OCL=21384
CL=21384

usr/gri/pretty/typechecker.go

@@ -0,0 +1,100 @@
+// 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 TypeChecker
+
+import (
+	AST "ast";
+	Universe "universe";
+	Globals "globals";
+	Object "object";
+	Type "type";
+)
+
+
+type State struct {
+	level int;
+	top_scope *Globals.Scope;
+}
+
+
+// ----------------------------------------------------------------------------
+// Support
+
+func (s *State) Error(pos int, msg string) {
+	panicln("error:" + msg);
+}
+
+
+// ----------------------------------------------------------------------------
+// Scopes
+
+func (s *State) OpenScope() {
+	s.top_scope = Globals.NewScope(s.top_scope);
+}
+
+
+func (s *State) CloseScope() {
+	s.top_scope = s.top_scope.parent;
+}
+
+
+func (s *State) Lookup(ident string) *Globals.Object {
+	for scope := s.top_scope; scope != nil; scope = scope.parent {
+		obj := scope.Lookup(ident);
+		if obj != nil {
+			return obj;
+		}
+	}
+	return nil;
+}
+
+
+func (s *State) DeclareInScope(scope *Globals.Scope, obj *Globals.Object) {
+	if s.level > 0 {
+		panic("cannot declare objects in other packages");
+	}
+	obj.pnolev = s.level;
+	if scope.Lookup(obj.ident) != nil {
+		s.Error(obj.pos, `"` + obj.ident + `" is declared already`);
+		return;  // don't insert it into the scope
+	}
+	scope.Insert(obj);
+}
+
+
+func (s *State) Declare(obj *Globals.Object) {
+	s.DeclareInScope(s.top_scope, obj);
+}
+
+
+// ----------------------------------------------------------------------------
+// Common productions
+
+func (s *State) DeclareIdent(kind int) {
+	obj := Globals.NewObject(0, kind, "");
+	s.Declare(obj);
+}
+
+
+// ----------------------------------------------------------------------------
+
+func (s *State) CheckProgram(p *AST.Program) {
+	s.OpenScope();
+	
+	{	s.OpenScope();
+	
+		s.CloseScope();
+	}
+	
+	s.CloseScope();
+}
+
+
+// ----------------------------------------------------------------------------
+
+export func CheckProgram(p *AST.Program) {
+	var s State;
+	s.CheckProgram(p);
+}