golang objset 代码
文件路径：/src/cmd/compile/internal/types2/objset.go
/ Copyright 2013 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.
/ This file implements objsets.
/
/ An objset is similar to a Scope but objset elements
/ are identified by their unique id, instead of their
/ object name.
package types2
/ An objset is a set of objects identified by their unique id.
/ The zero value for objset is a ready-to-use empty objset.
type objset map[string]Object / initialized lazily
/ insert attempts to insert an object obj into objset s.
/ If s already contains an alternative object alt with
/ the same name, insert leaves s unchanged and returns alt.
/ Otherwise it inserts obj and returns nil.
func (s *objset) insert(obj Object) Object {
id := obj.Id()
if alt := (*s)[id]; alt != nil {
return alt
}
if *s == nil {
*s = make(map[string]Object)
}
(*s)[id] = obj
return nil
}