LUA_TFUNCTION
luaL_checktype(L, 1, LUA_TFUNCTION);
#define ttisfunction(o) checktype(o, LUA_TFUNCTION)
#define ttisclosure(o) ((rttype(o) & 0x1F) == LUA_TFUNCTION)
#define LUA_TLCL (LUA_TFUNCTION | (0 << 4)) /* Lua closure */
#define LUA_TLCF (LUA_TFUNCTION | (1 << 4)) /* light C function */
#define LUA_TCCL (LUA_TFUNCTION | (2 << 4)) /* C closure */
check_exp(novariant((o)->gch.tt) == LUA_TFUNCTION, &((o)->cl))
luaL_checktype(L, 1, LUA_TFUNCTION);
case LUA_TFUNCTION: {
tr == LUA_TFUNCTION || tr == LUA_TTABLE, 3,
luaL_checktype(L, 2, LUA_TFUNCTION);
#define lua_isfunction(L,n) (lua_type(L, (n)) == LUA_TFUNCTION)