int w_ChainShape_setPreviousVertex(lua_State *L) { ChainShape *c = luax_checkchainshape(L, 1); if (lua_isnoneornil(L, 2)) c->setPreviousVertex(); else { float x = (float)luaL_checknumber(L, 2); float y = (float)luaL_checknumber(L, 3); luax_catchexcept(L, [&](){ c->setPreviousVertex(x, y); }); } return 0; }