In addition to back references, Perl also has forward and back assertions, IF/ELSE, and recursion IIRC. I'm not sure if anyone actually USES those features, but they are there.
Python adopted back references as well as forward and back assertions, but not the other stuff.
Perl really turned regular expressions into something else entirely...
Yes, I forgot about assertions. I've never _really_ used them, but I remember they were useful once or twice when wrangling with a particularly ugly format problem.
Python adopted back references as well as forward and back assertions, but not the other stuff.
Perl really turned regular expressions into something else entirely...