---
name: "Perl::Critic::Policy::ValuesAndExpressions::ProhibitBarewordDoubleColon"
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::ValuesAndExpressions::ProhibitBarewordDoubleColon"
---

# Perl::Critic::Policy::ValuesAndExpressions::ProhibitBarewordDoubleColon(3pm)

don't use Foo:: style barewords

## NAME

Perl::Critic::Policy::ValuesAndExpressions::ProhibitBarewordDoubleColon - don't use Foo:: style barewords

## DESCRIPTION

This policy is part of the `"Perl::Critic::Pulp"` add-on.  It asks you not to use the double-colon bareword like

```
    $class = Foo::Bar::;     # bad
```

but instead a plain string

```
    $class = 'Foo::Bar';     # ok
```

This is intended as a building block for a restricted coding style, or a matter of personal preference if you think the `"::"` is a bit obscure and that it's clearer to write a string when you mean a string.  On that basis the policy is lowest severity and under the "cosmetic" theme (see "POLICY THEMES" in Perl::Critic).

### Indirect Object Syntax

By default a double-colon is allowed in the indirect object syntax (see "Indirect Object Syntax" in perlobj).

```
    my $obj = new Foo::Bar:: $arg1,$arg2;   # ok
```

This is because `"::"` there is important to disambiguate a class name `"Foo::Bar"` from a function `"Foo::Bar()"`, ie. function `"Bar()"` in package `"Foo"`.

Whether you actually want indirect object syntax is a matter for other policies, like `"ProhibitIndirectSyntax"`. If you don't want the double-colon bareword then change to arrow style `"Foo::Bar->new($arg,...)"`.

### Double-Colon Advantages

The `"::"` bareword is for use on package names, not general bareword quoting.  If there's no such package at compile time a warning is given (see "Bareword "%s" refers to nonexistent package" in perldiag)

```
    my $class = No::Such::Package::;  # Perl warning
```

This warning can help pick up typos, though it relies on relevant packages being loaded at compile-time (ie. `"BEGIN"`).  If the package is loaded by a `"require"` at runtime then the warning fires even though the code runs correctly.  For reference, a warning isn't given for the indirect object syntax, which rather limits its benefit.

### Disabling

If you don't care about this you can always disable `"ProhibitBarewordDoubleColon"` from your *.perlcriticrc* in the usual way (see "CONFIGURATION" in Perl::Critic),

```
    [-ValuesAndExpressions::ProhibitBarewordDoubleColon]
```

## CONFIGURATION

- "allow\_indirect\_syntax" (boolean, default true)

  If true then allow double-colon in the indirect object syntax as shown above.  If false then report double-colons everywhere as violations

  ```
      # bad under allow_indirect_syntax=false
      my $obj = new Foo::Bar:: $arg1,$arg2;
  ```

  This can be controlled from your *~/.perlcriticrc* in the usual way.  For example

  ```
      [ValuesAndExpressions::ProhibitBarewordDoubleColon]
      allow_indirect_syntax=no
  ```

## SEE ALSO

Perl::Critic::Pulp, Perl::Critic, Perl::Critic::Policy::Objects::ProhibitIndirectSyntax

"`"Foo::"` can be used as implicitly quoted package name" in perl5005delta

## HOME PAGE

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

## COPYRIGHT

Copyright 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\>.