TWiki Plugins

• DefaultPlugin? : Optionally handles some legacy variables from older versions of TWiki. You can control this option from TWikiPreferences. (Perl programmers can also add rules for simple custom processing.)
• EmptyPlugin: Is a fully functional module, minus active code; it does nothing and serves as a template for new Plugin development.
• InterwikiPlugin: Use it for shorthand linking to remote sites, ex: TWiki:Plugins expands to TWiki:Plugins on TWiki.org. You can edit the predefined set of of Wiki-related sites, and add your own.
• EditTablePlugin: Edit TWiki tables using edit fields, date pickers and drop down boxes
• RenderListPlugin: Render bullet lists in a variety of formats
• SlideShowPlugin: Create web based presentations based on topics with headings.
• SmiliesPlugin: Render smilies as icons, like for  :-) or for  :eek:
• SpreadSheetPlugin: Add spreadsheet calculation like "$SUM( $ABOVE() )" to TWiki tables and other topic text
• TablePlugin: Control attributes of tables and sorting of table columns

A Note on Plugin Performance

• commonTagsHandler: Use it to expand %XYZPLUGIN% and %XYZPLUGIN{...}% variables
• startRenderingHandler: Use it for your own rendering rules or to overload TWiki's internal rendering like [[links]]

TWiki:Codev/StepByStepRenderingOrder helps you decide which rendering handler to use.

Hints on Writing Fast Plugins

• Delay the Plugin initialization to the actual function which is handling the tag. This way all the expensive initialization is done only when needed.
• For example, use an eval block like:
  eval { require IPC::Run }
return "<font color=\"red\">SamplePlugin: Can't load required modules ($@)</font>" if $@;
• You could return errors as strings to show what happened
• You can use a flag to avoid running the initialization twice