How to access vector components?

[Ono-Sendai]

If I pass a vector to a Luau script with lua_pushvector(script.thread_state, 1.0, 2.0, 3.0);
How can I access the vector components in Lua?

v.x etc. doesn't work.

[Ono-Sendai]

Ok looks like v.x does work usually, there is some issue when accessing a global vector (sandboxing?)
The error message does seem to be deceptive

[vegorov-rbx]

Currently, Luau doesn't come with a full vector library/metatable setup.
Only one access method has a fast-path included in the interpreter loop for performance.

To setup basic x/y/z access, you can do the following:

static int lua_vector_index(lua_State* L)
{
    const float* v = luaL_checkvector(L, 1);
    const char* name = luaL_checkstring(L, 2);

    int ic = (name[0]) - 'x';

    if (unsigned(ic) < 3 && name[1] == '\0')
    {
        lua_pushnumber(L, v[ic]);
        return 1;
    }

    luaL_error(L, "%s is not a valid member of vector", name);
}

static int lua_vector_namecall(lua_State* L)
{
    luaL_error(L, "%s is not a valid method of vector", luaL_checkstring(L, 1));
}

void setupVectorHelpers(lua_State* L)
{
    lua_pushvector(L, 0.0f, 0.0f, 0.0f);
    luaL_newmetatable(L, "vector");

    lua_pushcfunction(L, lua_vector_index, nullptr);
    lua_setfield(L, -2, "__index");

    lua_pushcfunction(L, lua_vector_namecall, nullptr);
    lua_setfield(L, -2, "__namecall");

    lua_setreadonly(L, -1, true);
    lua_setmetatable(L, -2);
    lua_pop(L, 1);
}

Index and namecall handlers can be extended with additional properties and methods.

[Ono-Sendai]

So what access method is the fast-path?

[vegorov-rbx]

.x/y/z on a local.

[Ono-Sendai]

Ok, thanks.