#include <iostream>
#include <lua.hpp>
using namespace std;

int mywrite(lua_State * L)
{
    int argc = lua_gettop(L);

    for ( int n = 1; n <= argc; ++n )
    {
        cout << lua_tostring(L, n);
    }

    return 0;
}

int val_handler(lua_State * L)
{
    int argc = lua_gettop(L);

    cout << "val_handler(): argc = " << argc << endl;
    lua_getfield(L, -1, "val");
    int the_val = lua_tointeger(L, -1);
    lua_pop(L, 1);

    cout << "val_handler(): the_val = " << the_val << endl;

    return 0;
}

int my_function(lua_State * L)
{
    int argc = lua_gettop(L);

    cerr << "-- my_function() called with " << argc
         << " arguments:" << endl;

    for ( int n = 1; n <= argc; ++n )
    {
        cerr << "-- argument " << n << ": "
             << lua_tostring(L, n) << endl;
    }

    /* construct return value */
    lua_newtable(L);
    lua_pushinteger(L, 42);
    lua_setfield(L, -2, "val");
    lua_pushcfunction(L, val_handler);
    lua_setfield(L, -2, "func");
    return 1; // number of return values
}

void report_errors(lua_State *L, int status)
{
    if ( status!=0 )
    {
        cerr << "-- " << lua_tostring(L, -1) << endl;
        lua_pop(L, 1); // remove error message
    }
}

int main(int argc, char ** argv)
{
    for ( int n = 1; n < argc; ++n )
    {
        const char * file = argv[n];

        lua_State * L = lua_open();

//        luaL_openlibs(L);
        luaL_Reg io_functions[] = {
            { "write", mywrite },
            { NULL, NULL }
        };
        luaL_register(L, "io", io_functions);

        // make my_function() available to Lua programs
        lua_register(L, "my_function", my_function);

        cerr << "-- Loading file: " << file << endl;

        int s = luaL_loadfile(L, file);

        if ( s == 0 )
        {
            // execute Lua program
            s = lua_pcall(L, 0, LUA_MULTRET, 0);
        }

        report_errors(L, s);
        lua_close(L);
        cerr << endl;
    }

    return 0;
}