Function trymt

third-party/lua-5.5.0/src/lstrlib.c:279–287

** To be here, either the first operand was a string or the first ** operand didn't have a corresponding metamethod. (Otherwise, that ** other metamethod would have been called.) So, if this metamethod ** doesn't work, the only other option would be for the second ** operand to have a different metamethod. */

** operand to have a different metamethod.
*/
static void trymt (lua_State *L, const char *mtkey, const char *opname) {
  lua_settop(L, 2);  /* back to the original arguments */
  if (l_unlikely(lua_type(L, 2) == LUA_TSTRING ||
                 !luaL_getmetafield(L, 2, mtkey)))
    luaL_error(L, "attempt to %s a '%s' with a '%s'", opname,
                  luaL_typename(L, -2), luaL_typename(L, -1));
  lua_insert(L, -3);  /* put metamethod before arguments */
  lua_call(L, 2, 1);  /* call metamethod */
}


static int arith (lua_State *L, int op, const char *mtname) {