Why does Perl's string multiplication not warn on undef?

Question

Under

use strict;
use warnings;
my $foo = undef;

the expressions

$foo . ''

and

"$foo"

both produce

Use of uninitialized value $foo in ... at ...

but the following expression gives the empty string without warning:

$foo x 1

Anyone knows why? I mean, it's cool to have a nice stringification idiom ($_ x 1 is quite much shorter than defined ? "$_" : ''), but it feels a bit weird.

Pride

I'm sure it wasn't intentional, at least not initially. – Wehrle

perldoc perlop (search for "Multiplicative Operators") doesn't say anything about the behavior of x with an undef left operand. I agree it's probably unintentional. – Pillbox

Answer 1

I once saw a show with a scene in a law school class. The instructor presented two similar cases to his students and asked why did they result in different rulings. It's because the rulings were made by judges, and judges are people, he eventually explained.

That should warn. The developers that work on Perl are people. Run perlbug to send a bug report if you wish.

Wehrle