golang map 代码
文件路径：/src/go/types/map.go
/ Copyright 2011 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 types
/ A Map represents a map type.
type Map struct {
key, elem Type
}
/ NewMap returns a new map for the given key and element types.
func NewMap(key, elem Type) *Map {
return &Map{key: key, elem: elem}
}
/ Key returns the key type of map m.
func (m *Map) Key() Type { return m.key }
/ Elem returns the element type of map m.
func (m *Map) Elem() Type { return m.elem }
func (t *Map) Underlying() Type { return t }
func (t *Map) String() string { return TypeString(t, nil) }