prefix.h

c/c++ win32/linux 通用的宏定义头文件，在不影响代码执行效率的前提下，用来美化代码的，整理了一下，个人感觉挺好用的。

源码如下：

prefix.h

//
//  prefix.h
//  otest
//
//  Created by leo_zhengyu on 2017/8/24.
//  Copyright © 2017年 cy0104. All rights reserved.
//
#ifndef prefix_h
#define prefix_h
#define cstr const char*
#define num double

//brief log
#ifdef DEBUG
#define PRINT(s) printf("%s\n",s)
#define LOG(s) printf("%s",s)
#define LOGI(s) printf("%d",s)
#else
#define PRINT(s)
#define LOG(s)
#endif

//start a varied array defination
#define ARR_START {
//end of array defination
#define ARR_END 0}

//a multi-lined string
#define TEXT(...) #__VA_ARGS__

//let <vn> from <start> to <end>
#define FOR(vn,start,end) {for(int vn=start;vn<=end;vn++){
//foreach <c> in string <s>
#define FOR_C_IN_S(s,c) {for(char* p##c = (char*)s;*p##c;p##c++){ char c = *pc;
//foreach <c> in string <s> including /0
#define FOR_C_IN_S_0(s,c) {for(char* p##c = (char*)s;p##c==s||*(p##c-1);p##c++){ char c = *pc;
//for <idx> in <arr>
#define FOR_I_IN_ARR(arr,idx) {for(int idx=0;idx<sizeof(arr)/sizeof(arr[0]);idx++){
//for <idx>:<ele> in <arr>
#define FOR_ELE_IN_ARR(arr,ele,idx) {for(int idx=0;idx<sizeof(arr)/sizeof(arr[0]);idx++){ typeof(arr[0]) ele = arr[idx];
//end block
#define END }}

//switch <fac>
#define SELECT(fac) {{typeof(fac) factor = fac;
//save as <tar>,use <typename _> if you dont need target varient
#define TO(tar) tar = (0)?0
//WARNING: invalid in stdc
#define ROW(k,v) :__IS_EQUAL(factor,v)
//a number case
#define ROW_I(k,v) :factor==k?(v)
//a string case
#define ROW_CS(k,v) :strcmp(factor,k)==0?(v)
//a default case,necessary
#define ROW_DEFAULT(v) :(v);

//macro alias
#define text TEXT
#define for_i FOR
#define for_c_in_s FOR_C_IN_S
#define for_c_in_s_0 FOR_C_IN_S_0
#define for_i_in_arr FOR_I_IN_ARR
#define for_ele_in_arr FOR_ELE_IN_ARR
#define end END
#define select SELECT
#define tab_k SELECT
#define to TO
#define row_cs ROW_CS
#define kv ROW_CS
#define row_i ROW_I
#define iv ROW_I
#define row_def ROW_DEFAULT
#define other(v) :(v);}}

//run a code-line.To run multi-lined codes,use || to combine.
#define eval(codes) (codes)*0

/*in c++ environment:
1.you are suggested to
use std::string instead of c-style string
and use kv instead of iv.
2.foreach ele in arr has a defer,which ele is a referance now.
*/
#if defined(__cplusplus) || defined(c_plusplus)
#define kv iv
#undef iv
#define FOR_ELE_IN_ARR(arr,ele,idx) {for(int idx=0;idx<sizeof(arr)/sizeof(arr[0]);idx++){ auto ele = arr[idx];
#endif

#endif /* prefix_h */

 主要的功能：
    0.复杂的字符串常量书写简化了，输入特殊字符不需要转义，默认忽略换行。

比如：

cstr s = text(name="leo");

    1.可以自己决定代码块缩进,排版更美观。

不缩进写法：

for_i(i,1,10)
...
end

 

缩进写法：

for_i(i,1,10)
{
    ...
}
end

 

或者:

{
    for_i(i,1,10)
    ...
    end
}

    2.for循环简化了，代码块结束配合关键字end。 
　　for以闭包方式执行，也就是说循环变量不会影响之后的代码，比以前更合理了。
　　for可以用最少的代码循环单个循环变量、遍历定长数组、遍历可变长数组。

例子：

for_i(i,1,10)//变量i只作用于代码段内
...
end
int j = i;//报错，i未定义

    3. switch／if else简化，代码更精简，映射关系一目了然,新的名字叫做tab_k。

例子：

tab_k(kname) to(target)
iv("1","one")
...
other("zero")

    在标准C下，可以使用iv和kv，kv用来方便的匹配char*;
    在cpp下，只有kv，k可以是任何类型，建议使用std::string代替char* 。
    另外， 如果想在v中执行代码，则需要配合eval关键字。
    匹配成功时，eval会执行括号内的代码。
    多条eval须使用||连接。
    4.变长数组初始化写法标准化，总是以0结尾，需要配合ARR_START和ARR_END。

下面这个是栗子，喜欢的话，快烤烤吃了吧。

    /*
     0.test of tab_k
     */
    int a=2;
    cstr b;
    
    tab_k(a) to(b)
    iv(0,"zero")
    iv(1,"one")
    iv(2,"two")
    iv(3,"three")
    other("number");
    
    cstr star;
    cstr sfac = "leo";
    
    tab_k(sfac) to(star)
    kv("leo",    "lzy")
    kv("wang","wh")
    kv("lee",    "lb")
    other("unknown");
    
    LOG(b);      //two
    LOG(star);  //lzy
    
    /*
     1.test of tab_k with eval
     */
    int c;
    
    tab_k(a) to(num _)//we dont care target varient
    iv(0,c=1)
    iv(1,eval(c=10)
       ||  eval(foo(c))
       )
    iv(2,eval(printf("first,"))
       ||  eval(c=100)
       ||  eval(printf("second,"))
       )
    iv(3,c=1000)
    other(0);
    //first,second,
    
    LOGI(c);    //100
    
    /*
     2.test of muti-lined string defination
     */
    char s[32] = text(
          {
              name:"leo",
              age:18,
          }
      );
    LOG(s);     //{ name:"leo", age:18, }
    
    /*
     3.test of brief for block
     */
    for_i(i,1,5)
    LOGI(i);
    end
    //12345
    
#pragma pack(4)
    typedef struct Player{
        cstr name;
        int  age;
        //align & bit-check
        int  suffix;
    }Player,*lpPlayer;
    
    Player players[4] =
    ARR_START
    {"l" "zy",  18, 1},
    {"w" "h",  56, 1},
    ARR_END;//end with 0
    
    for_ele_in_arr(players,p,i)
    LOG(p.name);
    end
    //lzy wh
    
    for_c_in_s(text(name="leo"),c)
    printf("%c",c);
    end
    //name="leo"