apparently NUL is mostly whitespace in Perl?

This post will be short but baffling.

In the following snippet, the ^@ sequences indicate literal NUL bytes in the source document.

use v5.36.0;
my $i = ^@ 1;
sub foo () {
 say q^@Hell0, w0rld.^@;


say ^@$i;

This program will run and print:

Hell0, w0rld.

The NUL bytes are all ignored… except for the two that act as the string delimiters for the q-operator. As near as I can tell without reading any of the source for the perl tokenizer (or related code), NUL is treated like whitespace. I am gobsmacked. I know all kinds of weird stuff about Perl, but this one surprised me.

It came up when I tried to run a bunch of small programs through perltidy, and it refused to process just one file, because it was “binary”. There was a NUL after a subroutine’s opening brace. I removed it out, but not because it was a syntax error. Just because it was not in good taste to leave it there.

Written on July 9, 2024
🐪 perl
🧑🏽‍💻 programming