Thread:Project:Support desk/php code in wiki/reply

I do not completely understand, what you want to do:

Do you want to display PHP code on one page in your wiki?

This works with the extension SyntaxHighlight_GeSHi. With it you can use

Or do you want to execute some PHP code, when a user of your wiki triggers a special action (like when he saves a page)?

This can be done using one of the hooks, which MediaWiki provides.