Center paragraphs
Mostly for examples, it can be of interest that it is easy to center a paragraph. Just add ||c|| to the paragraph.
| ||c|| $rc=function($arg); | 
This is called a PerlPoint paragraph filter. Please note that the paragraph itself (after the filter prefix) should begin as usual - the example paragraph needs to start with whitespaces, still.
Several filters can be chained:
| 
  ||co|c||  # call the function
    $rc=function($arg);
    #  | 
Index-related:
