如何防止List :: MoreUtils警告仅使用$ a和$ b一次? [英] How do I prevent List::MoreUtils from warning about using $a and $b only once?

问题描述

List::MoreUtils 模块指示您使用了变量$a提供与pairwise功能一起提供的BLOCK时的$b和$b.例如:

The List::MoreUtils module indicates that you use the variables $a and $b when supplying the BLOCK that goes with the pairwise function. For example:

use strict;
use warnings;
use List::MoreUtils qw'pairwise';

my @x = ( 1 ..  5);
my @y = (11 .. 15);
my @sums = pairwise { $a + $b } @x, @y;

但是当我这样做时，我会收到如下警告:

But when I do that, I get warnings like this:

Name "main::b" used only once: possible typo at try.pl line 7.
Name "main::a" used only once: possible typo at try.pl line 7.

有没有一种优雅的方法来解决这个问题?

Is there an elegant way to deal with this problem?

更新:

有关Perl v5.19.6及更高版本，请参见以太坊的答案:问题已解决.

See the answer by Ether for perl v5.19.6 and beyond: problem solved.

推荐答案

取决于您认为优雅的东西.

Depends on what you consider elegant.

no warnings qw(once);
our ($a, $b);

这两个就足够了.您甚至可以很容易地限制它们的范围.

One of these two will suffice. You can even limit their scope pretty easily.

my @sums = pairwise { no warnings qw(once); $a + $b } @x, @y;
my @sums = pairwise { our $a + our $b } @x, @y;

明确指定软件包也会抑制该警告.如果您在main，

Explicitly specifying the package will suppress the warning too. If you're in main,

my @sums = pairwise { $::a + $::b } @x, @y;

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