builtin regular expressions?

[Mirco Wahab]

Thus spoke Jorge Godoy (on 2006-09-30 14:37):
> Antoine De Groote <antoine at vo.lu> writes:
>> I'm sure there are good reasons, but I just don't see them.
>> Python Culture says: 'Explicit is better than implicit'. May it be related to
>> this?
> 
> See if this isn't better to read:
> 
> def print_message(some_str):
>     if some_str.startswith('track='):
>         print "Your track is", some_str[6:]
>     elif some_str.startswith('title='):
>         print "It's a title of", some_str[6:]
>     elif some_str.startswith('artist='):
>         print "It was played by", some_str[7:]
>     else:
>         print "Oops, I dunno the pattern for this line..."
>     return
> 
> for line in ['track="My favorite track"', 'title="My favorite song"',
>              'artist="Those Dudes"', 'Something else']:
>     print_message(line)

I don't see the point here, this example can be
translated amost 1:1 to Perl and gets much more
readable in the end, consider:


sub print_message {
   if   (/^(track=)/ ){ print 'Your track is '   .substr($_, length $1)."\n" }
   elsif(/^(title=)/ ){ print 'It\'s a title of '.substr($_, length $1)."\n" }
   elsif(/^(artist=)/){ print 'It was played by '.substr($_, length $1)."\n" }
   else               { print "Oops, I dunno the pattern for this line...\n" }
}

print_message for ( 'track="My favorite track"', 'title="My favorite song"',
                    'artist="Those Dudes"',      'Something else' );


Now one could argue if simple Regexes like
   /^track=/ are much worse compared to
more explicit formulations, like
   str.startswith('track=')

> I came from Perl and was used to think with regular expressions for
> everything.  Now I rarely use them.  They aren't needed to solve 
> most of the problems. 

OK, I do Perl and Python side by side and didn't reach
that point so far, maybe beause I read the Friedel-Book
 ( http://www.oreilly.com/catalog/regex2/reviews.html )
sometimes and actually *like* the concept of regular expressions.


Regards

Mirco