in reply to simple regex help

hi nmerriweather,

i'd like to not use an html tree module to handle this -- and keep it all in regex. is this possible?
In a word yes. But, imo, very tricky.

You didn't say what exactly you're looking for. Perhaps some examples, including those nested <li>s?

It's very easy to "get at" all the html elements. I'd wager a solution could be found using something like the following. 

#!/usr/bin/perl

use strict;
use warnings;
use HTML::TokeParser::Simple;

my $html = do{local $/; <DATA>};

my $p = HTML::TokeParser::Simple->new(\$html)
 or die "can't parse string: $!\n";

while (my $t = $p->get_token){
  printf "*%s*\n", $t->as_is;
}

__DATA__
<li><span class="title">Title</span> MATCH HERE </li>

[download]
output: 
*<li>*
*<span class="title">*
*Title*
*</span>*
* MATCH HERE *
*</li>*
*
*

[download]

Replies are listed 'Best First'.
Re^2: simple regex help
by nmerriweather (Friar) on Apr 18, 2007 at 17:08 UTC
    <quote>You didn't say what exactly you're looking for. Perhaps some examples, including those nested
  • s?</quote>

    Well, anything in the 'match here' -- the content changes. the only given i know, is that the outermost match is this: 

    <li><span class="title">Title</span> MATCH HERE </li>

    [download]

    MATCH here could be a single letter, or it could be an html structure that potentially matches the regex

    i really need to keep this in regex if possible -- using the tree objects is a last resort

[reply]
[d/l]
      I've used a stack to keep track of opening/closing li tags. 
      #!/usr/bin/perl

use strict;
use warnings;
use HTML::TokeParser::Simple;

my $html = do{local $/; <DATA>};

my $p = HTML::TokeParser::Simple->new(\$html)
 or die "can't parse string: $!\n";

while (my $t = $p->get_token){
  last if $t->is_end_tag('span');
}

my ($match, @li_stack);

while (my $t = $p->get_token){
  if ($t->is_start_tag('li')){
    push @li_stack, 'li';
  }
  if ($t->is_end_tag('li')){
    if (@li_stack){
      pop @li_stack;
    }
    else{
      last;
    }
  }
  $match .= $t->as_is;
}

print "$match\n";

__DATA__
<li><span class="title">Title</span><ul><li>one</li><li>two</li></ul> 
+MATCH HERE </li>

      [download]
      output: 
      <ul><li>one</li><li>two</li> MATCH HERE

      [download]
      update:
      Added output.

      uptdate 2
      see ikegami's reply below.

[reply]
[d/l]
[select]
        __DATA__
<li><span class="title">Title</span><ul><li>one</ul> MATCH HERE </li> 
+this shouldn't match

        [download]

        outputs 

        <ul><li>one</ul> MATCH HERE </li> this shouldn't match

        [download]

        instead of the expected 

        <ul><li>one</ul> MATCH HERE

        [download]
[reply]
[d/l]
[select]

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