examples/any_converter/any_converter.cpp

   1 #include <iostream>
   2
   3 extern "C"
   4 {
   5         #include "lua.h"
   6         #include "lauxlib.h"
   7         #include "lualib.h"
   8 }
   9
  10 bool dostring(lua_State* L, const char* str)
  11 {
  12         if (luaL_loadbuffer(L, str, std::strlen(str), str) || lua_pcall(L, 0, 0, 0))
  13         {
  14                 const char* a = lua_tostring(L, -1);
  15                 std::cout << a << "\n";
  16                 lua_pop(L, 1);
  17                 return true;
  18         }
  19         return false;
  20 }
  21
  22 #define LUABIND_NO_HEADERS_ONLY
  23
  24 #include <luabind/luabind.hpp>
  25 #include <boost/any.hpp>
  26
  27 template<class T>
  28 struct convert_any
  29 {
  30         static void convert(lua_State* L, const boost::any& a)
  31         {
  32                 typename luabind::detail::default_policy::template generate_converter<T, luabind::detail::cpp_to_lua>::type conv;
  33
  34                 conv.apply(L, *boost::any_cast<T>(&a));
  35         }
  36 };
  37
  38 std::map<const std::type_info*, void(*)(lua_State*, const boost::any&)> any_converters;
  39
  40 template<class T>
  41 void register_any_converter()
  42 {
  43         any_converters[&typeid(T)] = convert_any<T>::convert;
  44 }
  45
  46 namespace luabind
  47 {
  48         namespace converters
  49         {
  50                 yes_t is_user_defined(by_value<boost::any>);
  51                 yes_t is_user_defined(by_const_reference<boost::any>);
  52
  53                 void convert_cpp_to_lua(lua_State* L, const boost::any& a)
  54                 {
  55                         typedef void(*conv_t)(lua_State* L, const boost::any&);
  56                         conv_t conv = any_converters[&a.type()];
  57                         conv(L, a);
  58                 }
  59         }
  60 }
  61
  62 boost::any f(bool b)
  63 {
  64         if (b) return "foobar";
  65         else return "3.5f";
  66 }
  67
  68 int main()
  69 {
  70         register_any_converter<int>();
  71         register_any_converter<float>();
  72         register_any_converter<const char*>();
  73         register_any_converter<std::string>();
  74
  75         lua_State* L = lua_open();
  76         lua_baselibopen(L);
  77
  78         luabind::open(L);
  79         luabind::function(L, "f", &f);
  80
  81         dostring(L, "print( f(true) )");
  82         dostring(L, "print( f(false) )");
  83
  84         dostring(L, "function update(p) print(p) end");
  85
  86         boost::any param = std::string("foo");
  87
  88         luabind::call_function<void>(L, "update", param);
  89
  90         lua_close(L);
  91 }
  92