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 #include <luabind/luabind.hpp>
  23 #include <luabind/detail/convert_to_lua.hpp>
  24 #include <boost/any.hpp>
  25
  26 template<class T>
  27 struct convert_any
  28 {
  29         static void convert(lua_State* L, const boost::any& a)
  30         {
  31                 luabind::detail::convert_to_lua(L, *boost::any_cast<T>(&a));
  32         }
  33 };
  34
  35 std::map<const std::type_info*, void(*)(lua_State*, const boost::any&)> any_converters;
  36
  37 template<class T>
  38 void register_any_converter()
  39 {
  40         any_converters[&typeid(T)] = convert_any<T>::convert;
  41 }
  42
  43 namespace luabind
  44 {
  45         namespace converters
  46         {
  47                 yes_t is_user_defined(by_value<boost::any>);
  48                 yes_t is_user_defined(by_const_reference<boost::any>);
  49
  50                 void convert_cpp_to_lua(lua_State* L, const boost::any& a)
  51                 {
  52                         typedef void(*conv_t)(lua_State* L, const boost::any&);
  53                         conv_t conv = any_converters[&a.type()];
  54                         conv(L, a);
  55                 }
  56         }
  57 }
  58
  59 boost::any f(bool b)
  60 {
  61         if (b) return "foobar";
  62         else return 3.5f;
  63 }
  64
  65 int main()
  66 {
  67         register_any_converter<int>();
  68         register_any_converter<float>();
  69         register_any_converter<const char*>();
  70         register_any_converter<std::string>();
  71
  72         lua_State* L = lua_open();
  73 #if LUA_VERSION_NUM >= 501
  74         luaL_openlibs(L);
  75 #else
  76         lua_baselibopen(L);
  77 #endif
  78
  79         using namespace luabind;
  80
  81         open(L);
  82         module(L)
  83         [
  84                 def("f", &f)
  85         ];
  86
  87         dostring(L, "print( f(true) )");
  88         dostring(L, "print( f(false) )");
  89         dostring(L, "function update(p) print(p) end");
  90
  91         boost::any param = std::string("foo");
  92
  93         luabind::call_function<void>(L, "update", param);
  94
  95         lua_close(L);
  96 }
  97