Lua and C language call each other

#include <stdio.h>

#include <string.h>

#include <math.h>

#include <lua.h>

#include <lauxlib.h>

#include <lualib.h>

#include <stdarg.h>

#include <stdlib.h>

#define MAX_COLOR 255

static void stackDump(lua_State *L);

static int l_split(lua_State *L)

{

    const char *s = luaL_checkstring(L, 1);

    const char *sep = luaL_checkstring(L, 2);

    const char *e;

    int i = 1;

    lua_newtable(L);

    while ((e = strchr(s, *sep)) != NULL)

    {

        lua_pushlstring(L, s, e-s);

        lua_rawseti(L, -2, i ++);

        s = e + 1;

    }

    lua_pushstring(L, s);

    lua_rawseti(L, -2, i);

    return 1;

}

int l_map(lua_State *L)

{

    int i, n;

    luaL_checktype(L, 1, LUA_TTABLE);

    luaL_checktype(L, 2, LUA_TFUNCTION);

    n = lua_objlen(L, 1);

    for (i = 1; i <= n; i ++)

    {

        //stackDump(L);

        //printf("=====1=====\n");

        lua_pushvalue(L, 2);

        //stackDump(L);

        //printf("=====2=====\n");

        lua_rawgeti(L, 1, i);

        //stackDump(L);

        //printf("=====3=====\n");

        lua_call(L, 1, 1);

        //stackDump(L);

        //printf("=====4=====\n");

        lua_rawseti(L, 1, i);

        //stackDump(L);

        //printf("=====5=====\n");

    }

    return 0;

}

// 通过Lua调用的c函数，通过打印栈说明每个函数有独立的栈

// 将c函数注册到lua中，从而被lua调用。

static int l_sin(lua_State *L)

{

    double d = lua_tonumber(L, 1);

    lua_pushnumber(L, sin(d));

    // stackDump(L);

    // printf("====l_sin===\n");

    return 1;

}

// c 调用lua 函数

// 从Lua中得到函数，在c语言中传入参数。

double f(lua_State *L,double x, double y)

{

    double z;

    lua_getglobal(L, "f");

    lua_pushnumber(L, x);

    lua_pushnumber(L, y);

    // table function 1.1 2.2 说明c语言调用Lua会共享相同的栈.

    // stackDump(L);

    // printf("=====f=====\n");

    if (lua_pcall(L, 2, 1, 0) != 0)

        printf("call f error\n");

    if (!lua_isnumber(L, -1))

        printf("function f must return a number\n");

    z = lua_tonumber(L, -1);

    lua_pop(L, 1);

    return z;

}

int getfield(lua_State *L, const char *key)

{

    int result;

    // stackDump(L);

    // printf("==1==\n");

    lua_getfield(L, -1, key);

    // stackDump(L);

    // printf("==2==\n");

    if (!lua_isnumber(L, -1))

        printf("invalid component\n");

    result = lua_tonumber(L, -1);

    lua_pop(L, 1);

    // stackDump(L);

    // printf("==4==\n");

    return result;

}

static void stackDump(lua_State *L)

{

    int i;

    int top = lua_gettop(L);

    for (i = 1; i <= top; ++ i)

    {

        int t = lua_type(L, i);

        switch(t) {

        case LUA_TSTRING:

            printf("'%s'", lua_tostring(L, i));

            break;

        case LUA_TBOOLEAN:

            printf(lua_toboolean(L, i) ? "true" : "false");

            break;

        case LUA_TNUMBER:

            printf("%g", lua_tonumber(L, i));

            break;

        default:

            printf("%s", lua_typename(L, t));

            break;

        }

        printf(" ");

    }

    printf("\n");

}

void load(lua_State *L, const char *fname, int *w, int *h) {

    if (luaL_loadfile(L, fname) || lua_pcall(L, 0, 0, 0))

            printf("cannot run config.file\n");

    /*lua_getglobal(L, "height");

    lua_getglobal(L, "width");

    if (!lua_isnumber(L, -2))

        printf("width should be a number\n");

    if (!lua_isnumber(L, -1))

        printf("height should be a number\n");

    *w = lua_tointeger(L, -2);

    *h = lua_tointeger(L, -1);*/

    lua_getglobal(L, "table");

    if (!lua_istable(L, -1))

        printf("background should be table\n");

    printf("%f\n", f(L, 1.1, 2.2));

    float red = getfield(L, "r");

    float green = getfield(L, "g");

    float blue = getfield(L, "b");

    printf("%f, %f, %f\n", red, green, blue);

}

// lua 调用c代码可以模仿这里的格式

const char* testfunc = "t = mysplit(\"hi, hello\", \",\"); print(t[1], t[2])";

int main(void)

{

    char buff[256];

    int error;

    lua_State *L = luaL_newstate();

    luaL_openlibs(L);

    int w, h;

    // load(L, "test.lua", &w, &h);

    lua_pushcfunction(L, l_sin);

    lua_setglobal(L, "mysin");

    lua_pushcfunction(L, l_map);

    lua_setglobal(L, "mymap");

    lua_pushcfunction(L, l_split);

    lua_setglobal(L, "mysplit");

    if (luaL_dostring(L, testfunc))

        fprintf(stderr, "%s", lua_tostring(L, -1));

    /*

    while (fgets(buff, sizeof(buff), stdin) != NULL)

    {

        error = luaL_loadbuffer(L, buff, strlen(buff), "line");

        stackDump(L);

        error = error || lua_pcall(L, 0, 0, 0);

        stackDump(L);

    }

    if (error) {

        fprintf(stderr, "%s", lua_tostring(L, -1));

        lua_pop(L, 1);

    }*/

    lua_close(L);

    return 0;

}

BULE = {r = 0, g = 0, b = 1}

table = {["r"] = 10, ["g"] = 23, ["b"] = 33}

function f(x, y)

    return x + y

end