Vector2 and Vector3 should implement __idiv

[osyrisrblx]

Vector2 and Vector3 currently do not support the // operator in Lune, but they do in Roblox.

Should allow:

• Vector2 // Vector2 -> Vector2
• Vector2 // number -> Vector2
• Vector3 // Vector3 -> Vector3
• Vector3 // number -> Vector3

Pseudo code in Lua:

function Vector2:__idiv(other)
    if type(other) == "number" then
        return Vector2.new(
            math.floor(self.X / other),
            math.floor(self.Y / other)
        )
    else
        return Vector2.new(
            math.floor(self.X / other.X),
            math.floor(self.Y / other.Y)
        )
    end
end

function Vector3:__idiv(other)
    if type(other) == "number" then
        return Vector3.new(
            math.floor(self.X / other),
            math.floor(self.Y / other),
            math.floor(self.Z / other),
        )
    else
        return Vector3.new(
            math.floor(self.X / other.X),
            math.floor(self.Y / other.Y),
            math.floor(self.Z / other.Z),
        )
    end
end

[CompeyDev]

Floored division isn't a feature of luau, IIRC.

EDIT: Yes, turns out this is true. As per mlua docs, the IDiv metamethod can only be implemented for vanilla lua 5.x.

[CompeyDev]

Considering this is fairly simple to be implemented in pure luau, I question the requirement of having to implement this on Rust-side (i.e., providing a convenience function), especially considering the fact that it wouldn't integrate into luau well.

[LouieK22]

@CompeyDev As I understand Lune's Vector datatypes, they should support the same API surface as Roblox's Vector datatypes (https://github.com/lune-org/lune/blob/main/src/roblox/datatypes/types/vector3.rs#L19-L20). While not documented on their official docs, Roblox does support integer division for both Vector datatypes, so Lune should as well:

[CompeyDev]

We would need to implement a custom metamethod or something similar, no clue how that could be approached in mlua. Will update if there is a straightforward way to do it.

[LouieK22]

Presumably this should be escalated to an issue in mlua? The luau spec specifies that Luau supports the __idiv metamethod.

[CompeyDev]

You're correct, I'm able to use floored division in the vanilla luau REPL, but not in lune. That's odd.

[CompeyDev]

I've created an issue: mlua-rs/mlua#383.