---
name: "CPAN::Requirements::Dynamic"
section: "3pm"
platform: "linux"
package: "perl-cpan-requirements-dynamic"
version: "0.003-1"
release: "Arch Linux 2026-11-01"
platforms: ["linux"]
url: "https://new.carta.tech/CPAN::Requirements::Dynamic"
---

# CPAN::Requirements::Dynamic(3pm)

Dynamic prerequisites in meta files

## NAME

CPAN::Requirements::Dynamic - Dynamic prerequisites in meta files

## VERSION

version 0.003

## SYNOPSIS

```
 my $result = $dynamic->evaluate({
   expressions => [
     {
       condition => [ 'has_perl' => 'v5.20.0' ],
       prereqs => { Bar => "1.3" },
     },
     {
       condition => [ is_os => 'linux' ],
       prereqs => { Baz => "1.4" },
     },
     {
       condition => [ config_defined => 'usethreads' ],
       prereqs => { Quz => "1.5" },
     },
     {
       condition => [ and =>
         [ config_defined => 'usethreads' ],
         [ is_os => 'openbsd' ],
       ],
       prereqs => { Euz => "1.7" },
     },
     {
       condition => [ not => is_os_type => 'Unix'],
       error => 'OS unsupported',
     },
   ],
 });
```

## DESCRIPTION

This module implements a format for describing dynamic prerequisites of a distribution.

## METHODS

### new(%options)

This constructor takes two (optional but recommended) named arguments

- •

  config

  This is an ExtUtils::Config (compatible) object for reading configuration.

- •

  pureperl\_only

  This should be the value of the `"pureperl-only"` flag.

### evaluate(%options)

This takes a hash with two named arguments: `"version"` and `"expressions"`. The former is the version of the format, it currently defaults to 1. The latter is a list of hashes that can contain the following keys:

- •

  condition

  The condition of the dynamic requirement. This is an array with a name as first values and zero or more arguments following it. The semantics are described below under "Conditions"

- •

  prereqs

  The prereqs is a hash with modules for keys and the required version as values (e.g. `"{ Foo => '1.234' }"`).

- •

  phase

  The phase of the requirements. This defaults to `'runtime'`. Other valid values include `'build'` and `'test'`.

- •

  relation

  The relation of the requirements. This defaults to `'requires'`, but other valid values include `'recommends'`, `'suggests'` and `'conflicts'`.

- •

  error

  It will die with this error if set. The two messages `"No support for OS"` and `"OS unsupported"` have special meaning to CPAN Testers and are generally encouraged for situations that indicate not a failed build but an impossibility to build.

`"condition"` and one of `"prereqs"` or `"error"` are mandatory.

### evaluate\_file($filename)

This takes a filename, that can be either a YAML file or a JSON file, and evaluates it.

### Conditions

*can\_run($command)*

Returns true if a `$command` can be run.

*config\_defined($variable)*

This returns true if a specific configuration variable is defined.

*has\_env($variable)*

This returns true if the environmental variable with the name in `$variable` is true.

*has\_perl($version)*

Returns true if the perl version satisfies `$version`. `$version` is interpreted exactly as in the CPAN::Meta spec (e.g. `1.2` equals `'>= 1.2'`).

*is\_extended*

Returns true if extended testing is asked for.

*is\_os(@systems)*

Returns true if the OS name equals any of `@systems`.

*is\_os\_type($type)*

Returns true if the OS type equals `$type`. Typical values of `$type` are `'Unix'` or `'Windows'`.

*is\_smoker*

Returns true when running on a smoker.

*has\_env*

This returns true if the given environmental variable is true.

*want\_xs*

This returns true if a compiler appears to be available, and the `"pureperl_only"` option has not been set.

*not*

This takes an expression and negates its value.

*or*

This takes list of arrayrefs, each containing a condition expression. If at least one of the conditions is true this will also return true.

*and*

This takes a list of arrayrefs, each containing a condition expression. If all of the conditions are true this will also return true.

## AUTHOR

Leon Timmermans \<fawaka@gmail.com\>

## COPYRIGHT AND LICENSE

This software is copyright (c) 2023 by Leon Timmermans.

This is free software; you can redistribute it and/or modify it under the same terms as the Perl 5 programming language system itself.