Rexexp on part of a string

[Ovid]

--- virtualsue <virtuallysue at gmail.com> wrote:

> >> I would like to restrict the part of a string a regexp is allowed
> >> to operate on, For example I would like to ignore comments.
> >> I would like
> >>
> >>   $x = " andrew andrew   # andrew " ;
> >>   $x =~ s/andrew/black/g ;
> >> to produce " black black   # andrew "
<snip>
> > you could simply split() on #, s/andrew/black/g and rejoin
> > or use a lookahead
> > s/andrew(?=.*\#)/black/g;
> 
> If I split on # then what happens if $x contains 'print
> "==#andrew#andrew#===\n"  # more andrew'?
> 
> Maybe the data would never look like that, but calling them comments
> and using the '#' to delineate them makes you wonder.

I think the problem here is that we have an example of the data rather
than a specification of it.  The latter would make the question far
easier to answer :)

And if splitting the data makes sense, my Data::Record might come in
handy (http://search.cpan.org/dist/Data-Record/) because it gives the
programmer very fine-grained control over how to split data:

  use Regexp::Common;
  use Data::Record;
  my $record = Data::Record->new({
    split  => "\n",
    unless => $RE{quoted},
  });
  my @data = $record->records($data);

Cheers,
Ovid

--
Buy the book  - http://www.oreilly.com/catalog/perlhks/
Perl and CGI  - http://users.easystreet.com/ovid/cgi_course/
Personal blog - http://publius-ovidius.livejournal.com/
Tech blog     - http://use.perl.org/~Ovid/journal/