Banana NoMake，只需一个.h文件，直接使用C语言写脚本，取代那些令人生厌的gmake、nmake、cmake......

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项目地址：https://github.com/shajunxing/banana-nomake

我不喜欢那些构建系统，我认为他们带头违反了他们自己制定的“机制优于策略”和“KISS”原则。为什么要学习那些丑陋死板的规则？图灵完备的编程语言不更好吗？既然C编译器是必备的，那么把必要的功能封装进一个头文件里面，我总结最核心的就这几条：一、递归遍历文件目录；二、比较文件时间；三、串行、并行执行命令，不就能开心地用C语言写脚本了？客户也很高兴，因为他们完全不需要安装额外的构建系统，只需要键入gcc 脚本.c && ./a.out或者cl 脚本.c && 脚本.exe就行了，多方便？

简要指南：用listdir批量处理目录下面多个文件，用max mtime比较文件修改时间，用append concat endswith equals format join startswith处理字符串，用async await run执行命令。

比如某个项目，源代码位于src目录，编译生成的中间文件位于build目录，目标文件位于bin目录，因为C语言的字符串字面量支持直接拼接，所以可以很方便地定义出各文件、目录和命令行。

#define bin_dir "bin" pathsep
// ...
#define example_exe bin_dir "example" exeext
// ...
#ifdef _MSC_VER
    #define cc "cl /nologo /c /W3 /MD /Zp /utf-8 /std:clatest /O2 /Fo"
    #define ld "link /nologo /incremental:no /nodefaultlib /out:"
// ...

传统makefile的依赖关系，比如example_exe: example_obj var_h js_data_h js_common_h，其实就是比较冒号前后的文件的修改时间，如果前面的小于后面的，则执行接下来的命令，那么直接用C写出来，语义更清晰直观。

if (mtime(example_exe) < mtime(example_obj, var_h, js_data_h, js_common_h)) {
    run(link_example);
}

因为C是图灵完备的编程语言，可以轻松实现更复杂更灵活的逻辑，这是那些make系统完全无法比的。以下是完整的例子，其中用到async() await()多核并发执行命令，用C写起来所见即所得。而那些make系统即使能够实现，配置规则也会晦涩难懂。

#define bin_dir "bin" pathsep
#define build_dir "build" pathsep
#define src_dir "src" pathsep
#define banana_script_src_dir ".." pathsep "banana-script" pathsep "src" pathsep
#define js_common_h banana_script_src_dir "js-common.h"
#define js_common_c banana_script_src_dir "js-common.c"
#define js_common_obj build_dir "js_common" objext
#define js_data_h banana_script_src_dir "js-data.h"
#define js_data_c banana_script_src_dir "js-data.c"
#define js_data_obj build_dir "js_data" objext
#define var_h src_dir "var.h"
#define var_c src_dir "var.c"
#define var_obj build_dir "var" objext
#define example_c src_dir "example.c"
#define example_obj build_dir "example" objext
#define example_exe bin_dir "example" exeext
#ifdef _MSC_VER
    #define cc "cl /nologo /c /W3 /MD /Zp /utf-8 /std:clatest /O2 /Fo"
    #define ld "link /nologo /incremental:no /nodefaultlib /out:"
    #define extra_libs " msvcrt.lib libvcruntime.lib ucrt.lib kernel32.lib user32.lib"
#elif defined(__GNUC__)
    #define cc "gcc -c -Wall -O3 -o "
    #define ld "gcc -fvisibility=hidden -fvisibility-inlines-hidden -static -static-libgcc -s -Wl,--exclude-all-symbols -o "
    #define extra_libs ""
#else
    #error Only msvc and gcc are supported
#endif
#define compile_js_common cc js_common_obj " " js_common_c
#define compile_js_data cc js_data_obj " " js_data_c
#define compile_var cc var_obj " " var_c
#define compile_example cc example_obj " " example_c
#define link_example ld example_exe " " example_obj " " var_obj " " js_data_obj " " js_common_obj extra_libs

void build() {
    mkdir(bin_dir);
    mkdir(build_dir);
    // DON'T compare obj because it is generated asynchronously
    if (mtime(js_common_obj) < mtime(js_common_h, js_common_c)) {
        async(compile_js_common);
    }
    if (mtime(js_data_obj) < mtime(js_data_h, js_data_c, js_common_h)) {
        async(compile_js_data);
    }
    if (mtime(var_obj) < mtime(var_h, var_c, js_data_h js_common_h)) {
        async(compile_var);
    }
    if (mtime(example_obj) < mtime(example_c, var_h, js_data_h js_common_h)) {
        async(compile_example);
    }
    await();
    if (mtime(example_exe) < mtime(example_obj, var_h, js_data_h, js_common_h)) {
        run(link_example);
    }
}

void cleanup(const char *dir, const char *base, const char *ext) {
    if (base) {
        char *file_name = concat(dir, base, ext);
        remove(file_name);
        free(file_name);
    } else {
        listdir(dir, cleanup);
        rmdir(dir);
    }
}

int main(int argc, char **argv) {
    if (argc == 1) {
        build();
        return EXIT_SUCCESS;
    } else if (argc == 2) {
        if (equals(argv[1], "clean")) {
            listdir(bin_dir, cleanup);
            listdir(build_dir, cleanup);
            return EXIT_SUCCESS;
        } else if (equals(argv[1], "-h", "--help")) {
            ;
        } else {
            printf("Invalid target: %s\n", argv[1]);
        }
    } else {
        printf("Too many arguments\n");
    }
    printf("Usage: %s [clean|-h|--help]\n", argv[0]);
    return EXIT_FAILURE;
}

以下是详细的API定义：

Constants	Description
const enum compiler_type compiler	Compiler type, can be one of msvc gcc.
#define dllext	File extension of shared library, e.g ".dll" ".so"
#define exeext	File extension of executable, e.g ".exe"
#define libext	File extension of library, e.g ".lib" ".a"
#define objext	File extension of compiled object, e.g ".obj" ".o"
const enum os_type os	Operating system type, can be one of windows posix.
#define pathsep	File system path seperator, , e.g "\\" "/"

Functions	Description
void append(char **dest, ...)	Append multiple strings sequentially to end of dest, dest must be dynamically allocated.
void async(const char *cmd)	Parallel run command line cmd. Maximum number of workers equals to num of cpu cores. If return value is not 0, print error message and exit program.
void await()	Wait for all workers to finish.
char *concat(...)	Concatenate multiple strings, return string should be freed when used up.
bool endswith(const char *str, ...)	Determine whether str ends with any of rest parameters.
bool equals(const char *str, ...)	Determine whether str are equal to any of rest parameters.
char *format(const char *fmt, ...)	Format string like printf, return string should be freed when used up.
char *join(char *sep, ...)	Join multiple strings by given seperator sep, return string should be freed when used up.
void listdir(const char *dir, void (*callback)(const char *dir, const char *base, const char *ext))	Iterate all items in directory dir, whether dir ends with or without path seperator doesn't matter, for each item invoke callback, set 3 parameters: dir always ends with path seperator. If item is file, combination is complete file path, ext will be "" if file has no extension. If is directory, dir will be subdirectory's full path, base and ext will be NULL.
double max(...)	Take one or more double values, returns maximum one.
double mtime(...)	Get one or more file modification utc time and returns latest one, value for non-existent file is -DBL_MAX
void run(const char *cmd)	Run command line cmd. If return value is not 0, print error message and exit program.
bool startswith(const char *str, ...)	Determine whether str starts with any of rest parameters.