I find that anything involving a lot of regular expressions is easier to write in Perl than in Python. Perl and JavaScript are the only two mainstream languages I know of where regular expressions are first-class citizens (compared to Python, where you need to do `re.compile(r'...')` and store that somewhere).
Regexes are really easy in Ruby as well (which cribbed a lot from Perl). There's an OO syntax, but also support for the Perl built-ins so this works fine in Ruby:
print "match" if something =~ /thing/i
Captures with $1 etc. are there as are named captures using the same syntax in the regex.
The regex sublanguages and engines in Ruby and Python are knockoffs of the equivalents in earlier Perls.
But this thread really ought to be focused on Perl 6.
In Perl 6 one can write:
print "match" if something ~~ /<thing>/
It looks superficially similar. But it's a scalable parsing feature, not a mere regex. That line of code will work when `something` is ten thousand lines of complex Perl 6 code and `thing` is the top rule in a grammar for parsing Perl 6 code.
I was showing Ruby code to show how its regex handling is much like Perl 5 - Perl 5 would use a sigil on 'something'. Ruby is less like Perl 6 regex-wise due to the smart match (among many other things).
> Ruby is less like Perl 6 regex-wise due to the smart match (among many other things).
In both Perl 5 and Perl 6, smart match (`~~`) with a regex on the right hand side is just an alternate spelling (Perl 5) or correct spelling (Perl 6) for `=~`. It's a tiny, trivial difference.
But a Perl 6 "regex" can be an arbitrary full blown parser or compiler. And it assumes character=grapheme. In these two regards, as in several others, Perl 6 is quite unlike Perl 5 and other langs that adopted Perl 5 regexes and/or that adopted Unicode codepoints (or worse) rather than graphemes as their fundamental "character" unit.
You don't have to compile and store regexes in python. re.match(pattern, string) can be used right away and it will internally cache the compiled version of your most recently used patterns.
I'm also curious in which type of application regex is so important that it will be a deciding factor of language choice. I mean, if you have a regex in one out of 100 files, does it really matter if you have to write 2 lines instead of one.
