- implode: documentation ( source)
- explode: documentation ( source)
- sort: documentation ( source)
<?php
$a= explode ('|' , 'intro|chorus|verses?|chords|main|riff|bridge|pre|solo|legend|duration|misc|tablature|section|outro|middle|part|finish|once|twice|first|second|third|note|again|end(ing)?|start(ing)?|guitar|then|one|two|three|lyrics|pattern');
sort($a);
echo "'".implode("\n'",$a)."'";