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| | | | |               | ___ \ ___ \
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ULuaPP

Ubpa Lua++ (Lua & C++)

Auto register C++ class to Lua with sol2 and USRefl

Example

Suppose you have a class Vec, what you need to do are

• write TypeInfo<Vec> (you can use USRefl::AutoRefl to generate)
• register : Ubpa::ULuaPP::Register<Vec>(lua_State*)

That's all.

#include <ULuaPP/ULuaPP.h>
#include <iostream>

struct Vec {
  Vec(float x, float y) : x{ x }, y{ y } {}
  float x;
  float y;
  void Add(float dx = 1.f, float dy = 1.f) {
    x += dx;
    y += dy;
  }
};

template<>
struct Ubpa::USRefl::TypeInfo<Vec> :
  TypeInfoBase<Vec>
{
#ifdef UBPA_USREFL_NOT_USE_NAMEOF
  static constexpr char name[4] = "Vec";
#endif
  static constexpr AttrList attrs = {};
  static constexpr FieldList fields = {
    Field {TSTR(UMeta::constructor), WrapConstructor<Type(float, float)>()},
    Field {TSTR("x"), &Type::x},
    Field {TSTR("y"), &Type::y},
    Field {TSTR("Add"), &Type::Add, AttrList {
      Attr {TSTR(UMeta::default_functions), std::tuple {
        [](Type* __this, float dx) { return __this->Add(std::forward<float>(dx)); },
        [](Type* __this) { return __this->Add(); }
      }},
    }},
  };
};

int main() {
  lua_State* L = luaL_newstate(); /* opens Lua */
  luaL_openlibs(L); /* opens the standard libraries */

  // you just need to write a line of code
  Ubpa::ULuaPP::Register<Vec>(L);
	
  {
    sol::state_view lua(L);
    const char code[] = R"(
v = Vec.new(1, 2)
print(v.x, v.y)
v.x = 3
v.y = 4
print(v.x, v.y)
v:Add(1, 2)
v:Add(3)
v:Add()
print(v.x, v.y)
)";
    lua.script(code);
  }
  lua_close(L);
  return 0;
}