Re^2: Disable Perl warning

Occasionally, in very rare cases, a certain command may cause a warning that is spurious but unavoidable. In that case, you can enclose just the offending command in a lexical block and silence the warnings there only...

This is a necessary evil. While 99% of the time it's possible to, without jumping through coding hoops, code in such a way that produces no warnings, there is the 1% where the warning comes with the simplest use case:

use strict;
use warnings;

use List::Util qw( reduce );

print factorial(5), "\n";

sub factorial {
  return reduce { $a * $b } 1 .. $_[0] || 1;
}
__END__
__OUTPUT__
Name "main::a" used only once: possible typo at mytest.pl line 10.
Name "main::b" used only once: possible typo at mytest.pl line 10.
120
[download]

The only reasonable way to squelch that pair of warnings is to put "no warnings;" inside reduce's code block, and yet we're not doing anything even mildly devious.

Dave

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Re^3: Disable Perl warning by choroba (Cardinal) on Nov 27, 2012 at 10:37 UTC
The only reasonable way to squelch that pair of warnings is to put "no warnings;" inside reduce's code block Well, the other reasonable way is to put `no warnings 'once';` into the block. لսႽ† ᥲᥒ⚪⟊Ⴙᘓᖇ Ꮅᘓᖇ⎱ Ⴙᥲ𝇋ƙᘓᖇ	[reply] [d/l]
Re^4: Disable Perl warning by tobyink (Canon) on Nov 27, 2012 at 10:53 UTC
Within the scope of `use strict qw(subs vars)` the `once` warning is about a hundred times more annoying than it is useful. `void` and `uninitialized` are also of questionable value, and although the idea of `numeric` warnings is good, the details are silly... `use feature qw(say); use warnings qw(numeric); my $foo = ""; say $foo+1; # why does this warn, my $bar = []; say $bar+1; # when this does not?` [download] `perl -E'sub Monkey::do{say$_,for@_,do{($monkey=[caller(0)]->[3])=~s{::}{ }and$monkey}}"Monkey say"->Monkey::do'`	[reply] [d/l] [select]