C API、lua_newtable(), lua_gettable(), lua_settable()

everyday Lua 
/*
 * $ gcc -Wall -W -I/usr/include/lua50 -o 2008102900 -llua50 2008102900.c
 */

#include <stdio.h>
#include <lua.h>

int main(void) {
  lua_State *L;

  L = lua_open();

  lua_newtable(L);

  lua_pushstring(L, "foo");
  lua_gettable(L, 1);
  printf("%d\n", lua_isnil(L, -1));
  lua_pop(L, 1);

  lua_pushstring(L, "foo");
  lua_pushnumber(L, 10);
  lua_settable(L, 1);

  lua_pushstring(L, "foo");
  lua_gettable(L, 1);
  printf("%s\n", lua_typename(L, lua_type(L, -1)));
  printf("%d\n", (int)lua_tonumber(L, -1));

  lua_close(L);

  return 0;
}

で、

1
number
10