Category Archives: fixed feature

Perl 5.30 fixes single quoted qr” with \N{}

The qr// operator allows you to compile a regular expression without applying it to anything. You get the pattern without the match, and you can reuse the pattern as often as you like. Before v5.30, it had an inconsistency with \N{} sequences, but that’s fixed now.

In Perl v5.12, length(undef) returns undef.

Starting with v5.12, the length of an undefined value is undefined itself. Instead of converting the undef to the empty string then taking the length of that string, v5.12 returns undef: