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run code in 150+ php & hhvm versions
Bugs & Features
<?php function tagify($str, $baseUrl = '/board/') { $baseUrl = rtrim($baseUrl, '/'); return preg_replace('/ (?!<a[^<>]*>[^\#]*) # Dont match if there is an opening link tag and any chars after it. \#([-_\w]+\b) # Match the hashtag. (?![^<]*<\/a>) # Ignore any closing link tag including any chars before it not in hashtag. /ix', '<a href="'.$baseUrl.'/$1">#$1</a>', $str); } $str = <<<STR This is <a href="http://foo.com">This is #foo</a>. Simple #html-stuff text <a href="http://foobar.com#baz">#simple</a> <span class="simple">simple #simple text text</span> STR; echo tagify($str);
Output for 4.3.0 - 5.6.28, hhvm-3.10.0 - 3.12.0, 7.0.0 - 7.1.0
This is <a href="http://foo.com">This is #foo</a>. Simple <a href="/board/html-stuff">#html-stuff</a> text <a href="http://foobar.com#baz">#simple</a> <span class="simple">simple <a href="/board/simple">#simple</a> text text</span>