mirror of
https://github.com/golang/go
synced 2024-10-04 20:11:22 -06:00
9211a7d413
pointer types, supports literals, identifiers, type-checking most unary and binary operators, "compiling" a few unary and binary operators, and assignment and declaration statements. R=rsc APPROVED=rsc DELTA=1751 (1751 added, 0 deleted, 0 changed) OCL=31309 CL=31691
55 lines
1016 B
Go
55 lines
1016 B
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 eval
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import (
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"eval";
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)
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func NewRootScope() *Scope {
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return &Scope{nil, make(map[string] Def), 0};
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}
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func (s *Scope) Fork() *Scope {
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return &Scope{s, make(map[string] Def), 0};
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}
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func (s *Scope) DefineVar(name string, t Type) *Variable {
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if _, ok := s.defs[name]; ok {
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return nil;
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}
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v := &Variable{s.numVars, t};
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s.numVars++;
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s.defs[name] = v;
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return v;
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}
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func (s *Scope) DefineConst(name string, v Value) *Constant {
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if _, ok := s.defs[name]; ok {
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return nil;
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}
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c := &Constant{v.Type(), v};
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s.defs[name] = c;
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return c;
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}
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func (s *Scope) DefineType(name string, t Type) bool {
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if _, ok := s.defs[name]; ok {
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return false;
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}
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s.defs[name] = t;
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return true;
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}
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func (s *Scope) Lookup(name string) (Def, *Scope) {
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for s != nil {
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if d, ok := s.defs[name]; ok {
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return d, s;
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}
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s = s.outer;
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}
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return nil, nil;
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}
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