---
name: "Perl::Critic::Policy::Miscellanea::TextDomainUnused"
section: "3pm"
platform: "linux"
package: "libperl-critic-pulp-perl"
version: "99-1"
release: "Debian 13 (Trixie)"
platforms: ["linux"]
url: "https://new.carta.tech/Perl::Critic::Policy::Miscellanea::TextDomainUnused"
---

# Perl::Critic::Policy::Miscellanea::TextDomainUnused(3pm)

check for Locale::TextDomain imported but unused

## NAME

Perl::Critic::Policy::Miscellanea::TextDomainUnused - check for Locale::TextDomain imported but unused

## DESCRIPTION

This policy is part of the `"Perl::Critic::Pulp"` add-on.  It reports when you have `"Locale::TextDomain"` like

```
    use Locale::TextDomain ('MyMessageDomain');
```

but then don't use any of its functions or variables

```
    __ __x __n __nx __xn
    __p __px __np __npx
    N__ N__n N__p N__np
    %__ $__
```

`"Locale::TextDomain"` is not needed when not used, but it's also not actively harmful so this policy is only low severity and under the `"cosmetic"` theme (see "POLICY THEMES" in Perl::Critic).

The check is good if you've got `"Locale::TextDomain"` as boilerplate code in most of your program, but in some modules it's unused.  You can remove it entirely from non-interactive modules, or comment it out from modules which might have messages but don't yet.  The best thing picked up is when your boilerplate has got into a programmatic module which shouldn't say anything at the user level.

The saving from removing unused `"Locale::TextDomain"` is modest, just some imports and a hash entry holding the "textdomain" for the package.

It's easy to imagine a general kind of "module imported but unused" policy check, but in practice its hard for perlcritic to know the automatic imports of every module, and quite a few modules have side-effects, so this TextDomainUnused policy just starts with one case of an unused include.

### Interpolated Variables

The variables `"%__"` and `"$__"` are recognised in double-quote interpolated strings just by looking for a `"$__"` somewhere in the string, eg.

```
    print "*** $__{'A Message'} ***\n";  # ok
```

It's not hard to trick the recognition with escapes, or a hash slice style, but in general taking any `"$__"` to be a TextDomain use is close enough. (Perhaps in the future PPI will do a full parse of interpolated expressions.)

## SEE ALSO

Perl::Critic::Pulp, Perl::Critic, Locale::TextDomain, Perl::Critic::Policy::Miscellanea::TextDomainPlaceholders

## HOME PAGE

\<http://user42.tuxfamily.org/perl-critic-pulp/index.html\>

## COPYRIGHT

Copyright 2009, 2010, 2011, 2012, 2013, 2014, 2015, 2016, 2017, 2019, 2021 Kevin Ryde

Perl-Critic-Pulp is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation; either version 3, or (at your option) any later version.

Perl-Critic-Pulp is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for more details.

You should have received a copy of the GNU General Public License along with Perl-Critic-Pulp.  If not, see \<http://www.gnu.org/licenses/\>.