A little googling for "source filter" mod_perl uncovered this gem from a few years ago: http://www.issociate.de/board/post/363951/Using_%22switch%22_in_%3CPerl%3E_section..html. Search page for "source filter".

In reply to Re^3: Filtering failing under Apache & mod_perl? by kennethk
in thread Filtering failing under Apache & mod_perl? by clueless newbie

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