[golang]让golang支持泛型编程的一种方案

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总所周知，golang现在不支持泛型编程，对于习惯了C++泛型编程思想的程序员来说无疑是一个硬伤。
虽然golang interface{}多少可以满足一些泛型需求，但是无论在效率和编程手法上，都无法达到C++template那样的灵活性。出于对编译器效率的考虑，官方暂时还没有golang支持泛型的方案。
根据C++泛型的基本思路，我实现了一个名为gpg[1]的工具，使用工具通过文字替换的方式生成需要的.go代码，解决维护多个相似代码的尴尬，通过配置.gpg（ini）实例化模板文件(.gp)，替换相关模板参数
达到维护一份代码(.gp)，实现类型无关的编程思想。

如源码中example所示，假如需要实现一个未知类型的全局变量，需要在get和set的时候自动加锁，解决不同goroutine访问全局变量时的冲突。按照现有go规则，使用interface{}每次进行类型断言是一个办法，但是应用起来代码不好看，执行效率也没有原生类型快。
还有一个办法是用到什么类型，就把已经实现的代码拷贝一份改一改类型，这样一旦算法有修改，需要修改所有的实现代码，很不靠谱。
gpg可以解决以上所有问题. gpg的使用方法如下：
gpg tool 使用方法:
gpg-h 显示帮助
gpg 遍历当前目录所有.gpg文件 用同名的.gp文件作为模板生成.go代码文件
gpg 遍历path目录所有.gpg文件 用同名的.gp文件作为模板生成.go代码文件
//////////////////////////////////////////example.gp

//This is an example of using gpg tool forgeneric-programming

//this is an example of using gpg to define an auto-lock globalvalue with generic type

//it will be realized to real go code by gpg tool through the .gpgfile with the same name

package example
import (

"sync"

)
//auto locked global value

type AutoLockGbl struct {

val

lock sync.RWMutex

}
//new and init a global value

func New(val ) *AutoLockGbl{

p := &AutoLockGbl{}

p.val = val

return p

}
//get value, if modify is disable, lock is unneeded

func (me *AutoLockGbl) Get() (r ) {

me.lock.RLock()

defer me.lock.RUnlock()

r = me.val

return

}
//set value, if modify is disable, delete this function

func (me *AutoLockGbl) Set(val ) (r ) {

me.lock.Lock()

defer me.lock.Unlock()

r = me.val

me.val = val

return

}

//////////////////////////////////////////example.gpg
//分别用int,string,uint64实例化example.gp

;this is exactlly an ini file

;it is used to generate code from .gp file

[int]

TYPE_NAME=Int

VALUE_TYPE=int

LOCK_COMMENT=

;禁止修改，不需要锁

[const_str]

TYPE_NAME=ConstStr

VALUE_TYPE=string

LOCK_COMMENT=//

;禁止修改，不需要锁
[const_u64]

TYPE_NAME=ConstU64

VALUE_TYPE=uint64

LOCK_COMMENT=//

可以得到形如以下的代码文件
/////////////////////////////////example_gpg_int.go

// This file was auto-generated by [gpg] tool

// Last modify at: 2014-01-21 13:06:46.6378366 +0800 +0800

// !!!!!!!!!NEVER MODIFY IT MANUALLY!!!!!!!!!
//Copyright @Ally 2014. All rights reserved.

//Version: 1.0.0

//Author: vipally@gmail.com

//Blog site: http://blog.sina.com.cn/ally2014
//This is an example of using gpg tool forgeneric-programming

//this is an example of using gpg to define an auto-lock globalvalue with generic type

//it will be realized to real go code by gpg tool through the .gpgfile with the same name

package example
import (

"sync"

)
//auto locked global value

type AutoLockGblInt struct {

val int

lock sync.RWMutex

}
//new and init a global value

func NewInt(val int) *AutoLockGblInt{

p := &AutoLockGblInt{}

p.val = val

return p

}
//get value, if modify is disable, lock is unneeded

func (me *AutoLockGblInt) Get() (r int) {

me.lock.RLock()

defer me.lock.RUnlock()

r = me.val

return

}
//set value, if modify is disable, delete this function

func (me *AutoLockGblInt) Set(val int) (r int) {

me.lock.Lock()

defer me.lock.Unlock()

r = me.val

me.val = val

return

}

/////////////////////////////////example_gpg_const_str.go
// This file was auto-generated by [gpg] tool

// Last modify at: 2014-01-21 13:06:46.6408372 +0800 +0800

// !!!!!!!!!NEVER MODIFY IT MANUALLY!!!!!!!!!
//Copyright @Ally 2014. All rights reserved.

//Version: 1.0.0

//Author: vipally@gmail.com

//Blog site: http://blog.sina.com.cn/ally2014
//This is an example of using gpg tool forgeneric-programming

//this is an example of using gpg to define an auto-lock globalvalue with generic type

//it will be realized to real go code by gpg tool through the .gpgfile with the same name

package example
import (

//"sync"

)
//auto locked global value

type AutoLockGblConstStr struct {

val string

//lock sync.RWMutex

}
//new and init a global value

func NewConstStr(val string) *AutoLockGblConstStr{

p := &AutoLockGblConstStr{}

p.val = val

return p

}
//get value, if modify is disable, lock is unneeded

func (me *AutoLockGblConstStr) Get() (r string) {

// me.lock.RLock()

// defer me.lock.RUnlock()

r = me.val

return

}
//set value, if modify is disable, delete this function

//func (me *AutoLockGblConstStr) Set(val string) (r string) {

// me.lock.Lock()

// defer me.lock.Unlock()

// r = me.val

// me.val = val

// return

//}

这样基本可以满足golang对泛型的需求，而不需要付出额外代价。

本博客原创博文版权所有 @Allyvipally@gmail.com
仅供交流学习使用用于商业用途请联系原作者
转载请注明出处：http://blog.sina.com.cn/ally2014

[1] gpg源码 https://github.com/vipally/gpg