Loki系列一：优雅的Typelist

Typelist定义：

template

struct Typelist

{

typedef T Head;

typedef U Tail;

};

约定为Typelist的最后一个元素 : NullType 定义class NullType {};

约定Tail可以为另一个Typelist，这样就可以无限扩充，管理任意多的类型了

MakeTypelist定义：（为18个类型以内的Typelist提供帮助，足够用了）

template

<

typename T1  = NullType, typename T2  = NullType, typename T3  = NullType,

typename T4  = NullType, typename T5  = NullType, typename T6  = NullType,

typename T7  = NullType, typename T8  = NullType, typename T9  = NullType,

typename T10 = NullType, typename T11 = NullType, typename T12 = NullType,

typename T13 = NullType, typename T14 = NullType, typename T15 = NullType,

typename T16 = NullType, typename T17 = NullType, typename T18 = NullType

>

struct MakeTypelist

{

private:

typedef typename MakeTypelist

<

T2 , T3 , T4 ,

T5 , T6 , T7 ,

T8 , T9 , T10,

T11, T12, T13,

T14, T15, T16,

T17, T18

>

::Result TailResult;

public:

typedef Typelist Result;

};

template<>

struct MakeTypelist<>

{

typedef NullType Result;

};

如下使用：

typedef MakeTypelist::ResultIntegerTypes;

Typelist可以管理一堆型别，下篇再说下加于其上的一系列优雅的操作