luaembed

#include <stdlib.h>
#include <stdio.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <unistd.h>
#include <lua.h>
#include <lauxlib.h>
#include <lualib.h>

/*
print("Hello from Lua")
print("Lua code is capable of reading the value set from C++:",cppvar)
luavar = cppvar * 3

function myluafunction(times)
  return string.rep("(-)", times)
end

function myfunction(arg)
  return cppfunction(arg)
end

print("this string come from the lua script ö");
*/

static int l_cppfunction(lua_State *L) {
    double arg = luaL_checknumber(L,1);
    lua_pushnumber(L, arg * 0.5);
    return 1;
}

int main(int argc, char** argv)
{

  int outfile = open("luaoutput.txt", O_RDWR | O_CREAT, S_IRUSR | S_IWUSR);

  int ret = dup2(outfile, 1);
  if (ret == -1)
    perror("dup2");

  lua_State *L;
  L = luaL_newstate();
  luaL_openlibs(L);
  
  if (luaL_loadfile(L, "luas.lua")) {

    fprintf(stderr, "*** Something went wrong loading the chunk (syntax error?)\n");
    fprintf(stderr, "*** %s\n", lua_tostring(L, -1));
    lua_pop(L,1);
  }

  printf("iyed bennour\n");
  
  lua_pushnumber(L, 3.14);
  lua_setglobal(L, "cppvar");
  
  
  if (lua_pcall(L,0, LUA_MULTRET, 0)) {
    fprintf(stderr, "*** Something went wrong during execution\n");
    fprintf(stderr, "*** %s\n", lua_tostring(L, -1));
    lua_pop(L,1);
    exit(EXIT_FAILURE);
  }
  

  lua_getglobal(L, "luavar");
  double luavar = lua_tonumber(L,-1);
  lua_pop(L,1);
  fprintf(stderr, "*** C++ can read the value set from Lua luavar = = %f\n", luavar);
  
  fprintf(stderr, "*** Execute a Lua function from C++\n");
  lua_getglobal(L, "myluafunction");
  lua_pushnumber(L, 5);
  lua_pcall(L, 1, 1, 0);
  fprintf(stderr, "*** The return value of the function was %s\n", lua_tostring(L, -1));
  lua_pop(L,1);
  
  fprintf(stderr, "*** Execute a C++ function from Lua\n");
  fprintf(stderr, "*** First register the function in Lua\n");
  lua_pushcfunction(L, l_cppfunction);
  lua_setglobal(L, "cppfunction");
  
  fprintf(stderr, "*** Call a Lua function that uses the C++ function\n");
  lua_getglobal(L, "myfunction");
  lua_pushnumber(L, 5);
  lua_pcall(L, 1, 1, 0);
  fprintf(stderr, "*** The return value of the function was %f\n", lua_tonumber(L, -1));
  lua_pop(L,1);
  
  fprintf(stderr, "*** Release the Lua enviroment\n");
  lua_close(L);
  
}