[wp-trac] [WordPress Trac] #10702: Support for complex nested shorttags

[WordPress Trac]

#10702: Support for complex nested shorttags
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 Reporter:  pepijndevos              |       Owner:
     Type:  enhancement              |      Status:  new
 Priority:  normal                   |   Milestone:  Future Release
Component:  Shortcodes               |     Version:  2.9
 Severity:  normal                   |  Resolution:
 Keywords:  has-patch needs-testing  |
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Changes (by kovshenin):

 * keywords:  needs-patch => has-patch needs-testing


Comment:

 Hi there! My name is Konstantin and I love regular expressions (not!).
 Everybody says we should not parse HTML using a regular expression, and
 they're right. However, nobody said anything about using ''two'' (or more)
 regular expressions to parse HTML, so let's just do a bunch of loops :)

 [attachment:10702.diff] is an attempt to allow proper nested shortcodes in
 WordPress. The regex pattern has changed to use a positive lookahead and
 match the opening shortcode tag only if it's followed by its closing tag,
 meaning the search will match the inner tags first, which is why a loop
 has been introduced in `do_shortcode` and `strip_shortcodes` which will
 loop from the inner tags to the outer tags. This means that
 `preg_replace_callback` will run at least twice if a shortcode is present.

 [attachment:10702.unit-tests.diff] adds some test coverage.

 [attachment:10702.performance.csv] shows that there's a slight performance
 hit when the content has a lot of shortcodes. The "no shortcodes" and
 "some shortcodes" gains are probably due to the `strstr( $content, '[' )`
 short circuit in `do_shortcode`. The plugin that ran these tests can be
 found [https://gist.github.com/4016443 here].

 This is a draft and has room for improvement. Whatever we end up doing in
 `do_shortcode` should be equally done in `strip_shortcodes`. Also,
 escaping shortcodes might look a little weird with that string
 replacement, but since we're now replacing in a loop several times,
 replacing `[[` with `[` will no longer work. If you can think of a smarter
 way, I'm all ears!

 Your feedback is highly appreciated :)

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Ticket URL: <http://core.trac.wordpress.org/ticket/10702#comment:13>
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