Re: [css-values] [css-color] XSL-FO and CSS - expression languages compared

On Wed, Nov 16, 2016 at 9:05 PM, Florian Rivoal <florian@rivoal.net> wrote:
> It's been a while since I last though seriously about that, but I seem to remember that
> as long as we had something which was continuous, piece-wise linear, and strictly monotonic, we were good,
> and that breaking any of the three could mean complications.
>
> mod is piecewise linear, but not continuous or monotonic
> abs is piecewise linear and continuous, but not monotonic
> floor, ceiling, min and max are piecewise linear and continuous, and monotonic but not strictly monotonic
> round is piecewise linear but not continuous, and monotonic but not strictly monotonic
>
> I may be misremembering the criteria, and they may not all be of equal difficulty, though. I seem to remember this discussion being raised by dbaron, so maybe he remembers better.

I think you got it right. Point is that it needs to be invertible to
be usable in several spots in CSS, which those criteria satisfy.

~TJ