administrators (intermediate)
PmWiki's markup translation engine is handled by a set of rules; each rule searches for a specific pattern in the markup text and replaces it with some replacement text. Internally, this is accomplished by using PHP's "preg_replace" function.
Introduction
Rules are added to the translation engine via PmWiki's Markup() function, which looks like
Markup($name, $when, $pattern, $replace); # if no evaluation is needed, or if PHP < 5.5
match not begin/end of strings but also begin/end of lines (i.e., right before/after a newline). Also make sure your markup is executed during the fulltext phase.
How can the text returned by my markup function be re-processed by the markup engine?
If the result of your markup contains more markup that should be processed, you have two options. First is to select a "when" argument that is processed earlier than the markup in your result. For example, if your markup may return [[links]], your "when" argument could be "<links" and your markup will be processed before the links markup. The second option is to call the PRR() function in your markup definition or inside your markup function. In this case, after your markup is processed, PmWiki will restart all markups from the beginning.
How do I get started writing recipes and creating my own custom markup?
(alternate) Introduction to custom markup for Beginners
How do I make a rule that runs once at the end of all other rule processing?
Use this statement instead of the usual Markup() call:
$MarkupFrameBase['posteval']['myfooter'] = "\$out = onetimerule(\$out);";
This page may have a more recent version on pmwiki.org: PmWiki:CustomMarkup, and a talk page: PmWiki:CustomMarkup-Talk.
