/*
 * test.c
 * Example of a C program that interfaces with Lua.
 * Based on Lua 5.0 code by Pedro Martelletto in November, 2003.
 * Updated to Lua 5.1. David Manura, January 2007.
 */

#include <lua.h>
#include <lualib.h>
#include <lauxlib.h>
#include <stdlib.h>
#include <stdio.h>

static void dumpstack (lua_State *L) {
  int top=lua_gettop(L);
  printf("top is %i\n", top);
  for (int i=1; i <= top; i++) {
    printf("%d\t%s\t", i, luaL_typename(L,i));
    switch (lua_type(L, i)) {
      case LUA_TNUMBER:
        printf("%g\n",lua_tonumber(L,i));
        break;
      case LUA_TSTRING:
        printf("%s\n",lua_tostring(L,i));
        break;
      case LUA_TBOOLEAN:
        printf("%s\n", (lua_toboolean(L, i) ? "true" : "false"));
        break;
      case LUA_TNIL:
        printf("%s\n", "nil");
        break;
      default:
        printf("%p\n",lua_topointer(L,i));
        break;
    }
  }
}


int
main(void)
{
    int status, result, i;
    double sum;
    lua_State *L;

    /*
     * All Lua contexts are held in this structure. We work with it almost
     * all the time.
     */
    L = luaL_newstate();

    luaL_openlibs(L); /* Load Lua libraries */

  int top=lua_gettop(L);
  printf("top is %i\n", top);
    /* Load the file containing the script we are going to run */
    status = luaL_loadfile(L, "script2.lua");
    if (status) {
        /* If something went wrong, error message is at the top of */
        /* the stack */
        fprintf(stderr, "Couldn't load file: %s\n", lua_tostring(L, -1));
        exit(1);
    }
    lua_setglobal(L,"myFunc");

    /*
     * Ok, now here we go: We pass data to the lua script on the stack.
     * That is, we first have to prepare Lua's virtual stack the way we
     * want the script to receive it, then ask Lua to run it.
     */
    lua_newtable(L);    /* We will pass a table */

    /*
     * To put values into the table, we first push the index, then the
     * value, and then call lua_rawset() with the index of the table in the
     * stack. Let's see why it's -3: In Lua, the value -1 always refers to
     * the top of the stack. When you create the table with lua_newtable(),
     * the table gets pushed into the top of the stack. When you push the
     * index and then the cell value, the stack looks like:
     *
     * <- [stack bottom] -- table, index, value [top]
     *
     * So the -1 will refer to the cell value, thus -3 is used to refer to
     * the table itself. Note that lua_rawset() pops the two last elements
     * of the stack, so that after it has been called, the table is at the
     * top of the stack.
     */
    for (i = 1; i <= 5; i++) {
        lua_pushnumber(L, i);   /* Push the table index */
        lua_pushnumber(L, i*2); /* Push the cell value */
        lua_rawset(L, -3);      /* Stores the pair in the table */
    }

    /* By what name is the script going to reference our table? */
    lua_setglobal(L, "foo");

    /* Ask Lua to run our little script */
    dumpstack(L);
    lua_getglobal(L,"myFunc");
    dumpstack(L);
    result = lua_pcall(L, 0, 0, 0);
    if (result) {
        fprintf(stderr, "Failed to run script: %s\n", lua_tostring(L, -1));
        exit(1);
    }

    lua_newtable(L);    /* We will pass a table */

    /*
     * To put values into the table, we first push the index, then the
     * value, and then call lua_rawset() with the index of the table in the
     * stack. Let's see why it's -3: In Lua, the value -1 always refers to
     * the top of the stack. When you create the table with lua_newtable(),
     * the table gets pushed into the top of the stack. When you push the
     * index and then the cell value, the stack looks like:
     *
     * <- [stack bottom] -- table, index, value [top]
     *
     * So the -1 will refer to the cell value, thus -3 is used to refer to
     * the table itself. Note that lua_rawset() pops the two last elements
     * of the stack, so that after it has been called, the table is at the
     * top of the stack.
     */
    for (i = 1; i <= 5; i++) {
        lua_pushnumber(L, i);   /* Push the table index */
        lua_pushnumber(L, i*3); /* Push the cell value */
        lua_rawset(L, -3);      /* Stores the pair in the table */
    }

    /* By what name is the script going to reference our table? */
    lua_setglobal(L, "foo");
    lua_getglobal(L,"myFunc");
    result = lua_pcall(L, 0, 0, 0);
  lua_close(L);   /* Cya, Lua */

    return 0;
}