[chaosfox]

for those wondering, perl has this source filter feature [0] that allows implementation of these things, see also bleach [1] and ook [2] modules.

0. https://perldoc.perl.org/perlfilter.html

1. https://metacpan.org/pod/Acme::Bleach

2. https://metacpan.org/pod/Acme::Ook

[autarch]

Ook isn't a source filter, it's just the interpreter. But building a source filter on top of it would be pretty easy.