[RFC] Interval Comparison

Validating whether a number is within a closed or open interval is currently possible only via a construct like the following: ``` if (0 < $x && $x < 42) { echo 'x is in (0, 42)'; } if (0 <= $x && $x <= 42) { echo 'x is in [0, 42]'; } ``` 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. :) -- Richard "Fleshgrinder" Fussenegger