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// 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 ast
// A Scope maintains the set of identifiers visible
// in the scope and a link to the immediately surrounding
// (outer) scope.
//
// NOTE: WORK IN PROGRESS
//
type Scope struct {
Outer *Scope;
Names map[string]*Ident;
}
// NewScope creates a new scope nested in the outer scope.
func NewScope(outer *Scope) *Scope { return &Scope{outer, make(map[string]*Ident)} }
// Declare inserts an identifier into the scope s. If the
// declaration succeeds, the result is true, if the identifier
// exists already in the scope, the result is false.
//
func (s *Scope) Declare(ident *Ident) bool {
if _, found := s.Names[ident.Value]; found {
return false
}
s.Names[ident.Value] = ident;
return true;
}
// Lookup looks up an identifier in the current scope chain.
// If the identifier is found, it is returned; otherwise the
// result is nil.
//
func (s *Scope) Lookup(name string) *Ident {
for ; s != nil; s = s.Outer {
if ident, found := s.Names[name]; found {
return ident
}
}
return nil;
}
// TODO(gri) Uncomment once this code is needed.
/*
var Universe = Scope {
Names: map[string]*Ident {
// basic types
"bool": nil,
"byte": nil,
"int8": nil,
"int16": nil,
"int32": nil,
"int64": nil,
"uint8": nil,
"uint16": nil,
"uint32": nil,
"uint64": nil,
"float32": nil,
"float64": nil,
"string": nil,
// convenience types
"int": nil,
"uint": nil,
"uintptr": nil,
"float": nil,
// constants
"false": nil,
"true": nil,
"iota": nil,
"nil": nil,
// functions
"cap": nil,
"len": nil,
"new": nil,
"make": nil,
"panic": nil,
"panicln": nil,
"print": nil,
"println": nil,
}
}
*/
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