[jamienicol]

It could be because it matches the order of glsl's `mix()`. Not sure why glsl chose that order, though perhaps you might find it less unintuitive for an interpolation than a select. (Mix acts as a select rather than interpolation when the third argument is a boolean)

[skinner_]

That makes much sense, thanks! But then why didn't they call it mix() or lerp() or interpolate()? I would have immediately spotted the logic behind it.

EDIT: I think I get it, there also a mix() with a different type signature but same parameter order.