---
name: "Perl::Critic::Policy::BuiltinFunctions::ProhibitReverseSortBlock"
section: "3pm"
platform: "linux"
package: "perl-perl-critic"
version: "1.156-3"
release: "Arch Linux 2026-11-01"
platforms: ["linux"]
url: "https://new.carta.tech/Perl::Critic::Policy::BuiltinFunctions::ProhibitReverseSortBlock"
---

# Perl::Critic::Policy::BuiltinFunctions::ProhibitReverseSortBlock(3pm)

Forbid $b before $a in sort blocks.

## NAME

Perl::Critic::Policy::BuiltinFunctions::ProhibitReverseSortBlock - Forbid $b before $a in sort blocks.

## AFFILIATION

This Policy is part of the core Perl::Critic distribution.

## DESCRIPTION

Conway says that it is much clearer to use `"reverse"` than to flip `$a` and `$b` around in a `"sort"` block.  He also suggests that, in newer perls, `"reverse"` is specifically looked for and optimized, and in the case of a simple reversed string `"sort"`, using `"reverse"` with a `"sort"` with no block is faster even in old perls.

```
    my @foo = sort { $b cmp $a } @bar;         #not ok
    my @foo = reverse sort @bar;               #ok
    my @foo = sort { $b <=> $a } @bar;         #not ok
    my @foo = reverse sort { $a <=> $b } @bar; #ok
```

## CONFIGURATION

This Policy is not configurable except for the standard options.

## AUTHOR

Chris Dolan \<cdolan@cpan.org\>

## COPYRIGHT

Copyright (c) 2006-2011 Chris Dolan.

This program is free software; you can redistribute it and/or modify it under the same terms as Perl itself.