---
name: "Perl::Critic::Policy::BuiltinFunctions::ProhibitComplexMappings"
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::ProhibitComplexMappings"
---

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

Map blocks should have a single statement.

## NAME

Perl::Critic::Policy::BuiltinFunctions::ProhibitComplexMappings - Map blocks should have a single statement.

## AFFILIATION

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

## DESCRIPTION

The map function can be confusing to novices in the best of circumstances.  Mappings with multiple statements are even worse. They're also a maintainer's nightmare because any added complexity decreases readability precipitously.  Why?  Because map is traditionally a one-liner converting one array to another.  Trying to cram lots of functionality into a one-liner is a bad idea in general.

The best solutions to a complex mapping are: 1) write a subroutine that performs the manipulation and call that from map; 2) rewrite the map as a for loop.

## CAVEATS

This policy currently misses some compound statements inside of the map.  For example, the following code incorrectly does not trigger a violation:

```
    map { do { foo(); bar() } } @list
```

## CONFIGURATION

By default this policy flags any mappings with more than one statement.  While we do not recommend it, you can increase this limit as follows in a *.perlcriticrc* file:

```
    [BuiltinFunctions::ProhibitComplexMappings]
    max_statements = 2
```

## AUTHOR

Chris Dolan \<cdolan@cpan.org\>

## CREDITS

Initial development of this policy was supported by a grant from the Perl Foundation.

## COPYRIGHT

Copyright (c) 2007-2011 Chris Dolan.

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