Yes and? Your qr// expression interpolated and then fixed the constant into place. Normally I'd just eschew that as a particularly ugly form of a regex though. In fact, I'd likely have written that as this instead. I'd be using the constant like its intended (as in, not like a cleverly named function) and I still get something reasonable. Now other people like Perrin have been convincing me that constant isn't all that great anyway especially given the bareword quoting rules with the => fat comma and interpolation (like you noticed).

use constant FOO => 'bar';
my $x = FOO;
$x = qr/$x/;

"somehting" =~ $x
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So actually, I wouldn't have written it at all like that. This is more likely. Though I wouldn't have gone out of my way to create a qr// object if I was only going to use it in one place anyway. That looks like something that'd be better written as merely "something" =~ $FOO.

our $FOO = 'bar';
my $x = qr/$FOO/;

"something" =~ $x;
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