Filtering imported examples

Paragraph filters can be applied to examples that were imported from files, which allows to show up to date source code highlighted automatically. To achive this, one could use the filter from the previous section and write

||cp|c||\INCLUDE{ type=parsedexample file="source.pl"}

Please note that it is required to set the type option of \INCLUDE to parsedexample, not example. The reason for this is that example includes the file as a verbatim block. Filters are applied to verbatim blocks, too, but our filter does not change the paragraph type, which means the highlightning tags are included - but not processed after filtering. Of course, one could avoid this by making the filter transform verbatim blocks into parsed example blocks - but it is simpler to use parsedexample.