This is a PHP port of the python module for writing pandoc filters found at https://github.com/jgm/pandocfilters

The purpose is simply to make it easier to write filters in PHP

#!/usr/bin/env php <?php require_once __DIR__ . '/../pandocfilters.php'; Pandoc_Filter::toJSONFilter(function ($type, $value, $format, $meta) { if ('Str' == $type) { // use mb_convert_case instead of ucwords so filter works with unicode return mb_convert_case($value, MB_CASE_TITLE, "UTF-8"); } });

More examples and more information can be found in the original repository. Dave Jarvis has opened a PR with a bit more information. Until it is merged it can be found here:
https://github.com/DaveJarvis/pandocfilters/tree/patch-1

Thanks to John MacFarlane for pandoc.