From: Jeff 'japhy' Pinyan <jeffp@...>
Date: 2002-02-14T00:54:33+09:00
Subject: Re: simple XML parsing (greedy / non-greedy

[posted & mailed]

On Feb 13, Ron Jeffries said:

>Suppose I had this text
>
>	'<a>this is a</a><a>this is a also</a>'
>
>and I wanted to write a regexp that would match the tag <a>..</a> and

No one has told you yet that regexes are a bad idea here.  I'm *sure* Ruby
has XML-parsing libraries.  Using regexes here will be more work than
you'd like.  Consider:

  <a>this <a>that</a> those</a>

What does your non-greedy regex match now?  It matches from <a> to the
first </a>, which happens to INCLUDE an <a>.  So now you've matched

  <a>this <a>that</a>

and you have icky stuff left.

>(I do know I could go to a real XML parser, and maybe I will. Right now
>I'm just looking to extract some moderately simple stuff ...

I hope it's *very* simple and *very* predictable.  Otherwise, you'll be in
for some unpleasant surprises.

-- 
Jeff "japhy" Pinyan      japhy@pobox.com      http://www.pobox.com/~japhy/
RPI Acacia brother #734   http://www.perlmonks.org/   http://www.cpan.org/
** Look for "Regular Expressions in Perl" published by Manning, in 2002 **
<stu> what does y/// stand for?  <tenderpuss> why, yansliterate of course.
[  I'm looking for programming work.  If you like my work, let me know.  ]