(!) The following four chapters are about advanced details. If you don't care about this, you can just skip them.

MoinMoin is built in a quite modular way, so its functions are expandable by using plug-ins. Macros, parsers, actions, etc. can either be built-in, included, or installed as a plug-in.

A macro is entered as wiki markup and it processes a few parameters to generate an output, which is displayed in the content area.

A parser is entered as wiki markup and it processes a few parameters and a multiline block of text data to generate an output, which is displayed in the content area.

An action is mostly called using the menu (or a macro) and generates a complete HTML page on its own.