I use a little mini language I wrote with the preprocessor. You can figure out your own way of doing it , but I've included the whole thing below because it's so simple. In terms of usage it goes like this:
You can also add support for passing custom data objects like point's or whatever. Experiment with your own system and find something that works. My code is pretty ugly but it works fine, and contrary to orthodoxy, macro's when used purposefully, are not evil!
//
// CHECK
//
template<typename T> T _ark_lua_check (lua_State*, int&);
template<> int _ark_lua_check (lua_State* ls, int& n)
{
luaL_checktype(ls, n, LUA_TNUMBER);
return (int)(lua_tointeger(ls, n++));
}
template<> float _ark_lua_check (lua_State* ls, int& n)
{
luaL_checktype(ls, n, LUA_TNUMBER);
return (float)(lua_tonumber(ls, n++));
}
template<> bool _ark_lua_check (lua_State* ls, int& n)
{
luaL_checktype(ls, n, LUA_TBOOLEAN);
return lua_toboolean(ls, n++);
}
template<> std::string _ark_lua_check (lua_State* ls, int& n)
{
luaL_checktype(ls, n, LUA_TSTRING);
return lua_tostring(ls, n++);
}
template<> void * _ark_lua_check (lua_State* ls, int& n)
{
if(lua_type(ls, n) != LUA_TUSERDATA &&
lua_type(ls, n) != LUA_TLIGHTUSERDATA)
{
// Force informative error.
luaL_checktype(ls, n, LUA_TUSERDATA);
}
return lua_touserdata(ls, n++);
}
inline void my_checktable (lua_State * ls, int n)
{
if(lua_type(ls, n) != LUA_TTABLE)
{
cerr << "C function expected a table, got a "
<< lua_typename(ls, n) << endl;
luaL_checktype(ls, n, LUA_TTABLE); // force error
}
}
//
// TYPE
//
bool _ark_lua_is_Int (lua_State* ls, int n)
{ return lua_isnumber(ls, n); }
bool _ark_lua_is_Float (lua_State* ls, int n)
{ return lua_isnumber(ls, n); }
bool _ark_lua_is_Bool (lua_State* ls, int n)
{ return lua_isboolean(ls, n); }
bool _ark_lua_is_String (lua_State* ls, int n)
{ return lua_isstring(ls, n); }
bool _ark_lua_is_Data (lua_State* ls, int n)
{
return lua_type(ls, n) == LUA_TUSERDATA ||
lua_type(ls, n) == LUA_TLIGHTUSERDATA;
}
//
// GET
//
template<typename T> T _ark_lua_get (lua_State*, int);
template<> int _ark_lua_get (lua_State* ls, int n)
{ return (int)(lua_tointeger(ls, n)); }
template<> float _ark_lua_get (lua_State* ls, int n)
{ return (float)(lua_tonumber(ls, n)); }
template<> bool _ark_lua_get (lua_State* ls, int n)
{ return lua_toboolean(ls, n); }
template<> std::string _ark_lua_get<std::string> (lua_State* ls, int n)
{ return lua_tostring(ls, n); }
template<> void * _ark_lua_get (lua_State* ls, int n)
{ return lua_touserdata(ls, n); }
//
// PUSH
//
template<typename T> int _ark_lua_push (lua_State*, T);
template<> int _ark_lua_push (lua_State* ls, int v)
{ lua_pushnumber(ls, v); return 1; }
template<> int _ark_lua_push (lua_State* ls, float v)
{ lua_pushnumber(ls, v); return 1; }
template<> int _ark_lua_push (lua_State* ls, bool v)
{ lua_pushboolean(ls, v); return 1; }
template<> int _ark_lua_push (lua_State* ls, std::string v)
{ lua_pushstring(ls, v.c_str()); return 1; }
template<> int _ark_lua_push (lua_State* ls, void * v)
{
if(v)
lua_pushlightuserdata(ls, v);
else
lua_pushnil(ls);
return 1;
}
typedef int Param_Int;
typedef float Param_Float;
typedef bool Param_Bool;
typedef std::string Param_String;
typedef void * Param_Data;
#define Lparm(TypeName, parm) \
Param_##TypeName parm = _ark_lua_check<Param_##TypeName>(ls, _arg_count);
#define Lopts(TypeName, parm, def) \
Param_##TypeName parm = def; \
if(_ark_lua_is_##TypeName(ls, _arg_count)) { \
parm = _ark_lua_get<Param_##TypeName>(ls, _arg_count++); }
#define Lself(type) \
my_checktable(ls, 1); \
lua_pushstring(ls, "core"); \
lua_gettable(ls, 1); \
lua_insert(ls, 2); \
++_arg_count; \
type * self = (type*) _ark_lua_check<Param_Data>(ls, _arg_count); (void)self;
#ifdef Lfunc
#undef Lfunc
#endif
#define Lfunc(fun) \
extern "C" int fun (lua_State* ls) { \
int _arg_count = 1; (void)_arg_count; try {
#define Lmeth(type, fun) \
extern "C" int type##_##fun (lua_State* ls) \
{ int _arg_count = 1; Lself(type) try {
#define Lload(fun) \
lua_register(ls, #fun, fun);
#define Lret0 \
lua_settop(ls, 0); } ARK_CATCH; \
return 0; }
#define Lretv(ret) \
lua_settop(ls, 0); \
return _ark_lua_push(ls, ret); \
} ARK_CATCH; return 0; }
#define Lret1 \
lua_insert(ls, 1); \
lua_settop(ls, 1); \
return 1; } ARK_CATCH; return 0; }
#define Lret2 \
lua_insert(ls, 1); \
lua_insert(ls, 2); \
lua_settop(ls, 2); \
return 2; } ARK_CATCH; return 0; }
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