Writing mediawiki extensions

Here is the simplest mediawiki extension you can write:

• in LocalSettings.php, add

include("extensions/circlextension.php");

• create a file extensions/circlextension.php:

<?php

$wgExtensionFunctions[] = "wfcirclextension";

function wfcirclextension()
{
  global $wgParser;
  $wgParser->setHook("circle", "circlehtml");
}

function circlehtml($code, $argv)
{
  $result="<svg><circle r=50 /></svg>";
  return $result;
}

• Now you can create a mediawiki page with the content

This is mediawiki-syntax
<circle this goes into argv >
this goes into code
</circle>

• And you will see a circle on the resulting wiki page. Note the circle may not be complete.

Version 2

Version 2 could look like this:

<?php

$wgExtensionFunctions[] = "wfcirclextension";

function wfcirclextension()
{
  global $wgParser;
  $wgParser->setHook("circle", "circlehtml");
}

function circlehtml($code, $argv)
{
  $param=reset($argv); # get first value of array
  if (!is_numeric($param)) {$param=20;};
  $result="
<svg width=".round($param*2)." height=".round($param*2).">
  <circle r=$param cx=$param cy=$param />
</svg>";
  $result=preg_replace("/\n/","",$result);
  return $result;
}