Re: [RFC] Interval Comparison

Hi, Fleshgrinder wrote:

It is not very readable and repetitive. It would be interesting to support a more mathematical notation for this:

if (0 < $x < 42) {
     echo 'x is in (0, 42)';
}

if (0 <= $x <= 42) {
     echo 'x is in [0, 42]';
}

I cannot judge how complicated it is to extend the Bison definitions to allow this. However, if there is interest I'm sure there is a way. :)

Python supports this, I believe it lets you use arbitrary chains of comparisons. PHP is in the fortunate position where the associativity of the comparison operators is undefined. That is, 0 < $x < 42 is currently invalid syntax. Some other languages made the (in my view) mistake of defining a precedence here, so that it gets interpreted as `(0 < $x) < 42`, which is (generally?) useless. PHP doesn't have this problem. I've wanted to do this myself, but figuring out how to implement it was tricky, so I didn't spend much time on it. But it's certainly possible, and I'd appreciate this if it was added. Thanks for bringing it up! -- Andrea Faulds https://ajf.me/