CODEWITHSUNDEEP
c++lua
akaltar
akaltar

Reputation: 1097

Lua in-place initialized table order

I want to be able to do the following:

MyObject:SetSize( { 10.0, 20.0 } )

But when I iterate over this on the C-side (SetSize is a C function). The order of the parameters is random.

This is the C++ side processing the table:

glm::vec2 State::PopVec2()
{
    glm::vec2 v();

    lua_pushnil( ls ); // first key

    int i = 0;
    while( lua_next( ls, -2 ) ) // pops key and pushes next key and value
    {
        // v[0] is x coordinate. v[1] is y coordinate.
        v[i] = (float)lua_tonumber( ls, -1 ); // get number

        lua_pop( ls, 1 );// pop value but leave next key.

        ++i;
    }

    lua_pop( ls, 1 ); // pop table

    return v;
}

How could I ensure consistent order without having to mess up the code on the lua side? (So basically solve this on the C++ side)

Or alternatively, what should I use as a "Vec2" equivalent on the lua side?

Upvotes: 2

Views: 325

Answers (1)

Puppy
Puppy

Reputation: 146968

You should push 1 and 2 on to the stack (or 0,1 if tables are 0indexed) and use lua_geti instead of iterating over the table with lua_next. Another example of how your current code is incorrect is what happens if the Lua user passes {1, 2, 3}? You would be accessing the 3rd element of a 2-element vector.

Upvotes: 3

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