NAME

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

VERSION

version 0.001

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 => [ has_module => 'CPAN::Meta', '2' ],
       prereqs => { Wuz => "1.6" },
     },
     {
       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_xs

This returns true if a compiler appears to be available.

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_module($module, $version = 0)

Returns true if a module is installed on the system. If a $version is given, it will also check if that version is provided. $version is interpreted exactly as in the CPAN::Meta spec.

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_interactive

Returns true if installed from a terminal that can answer prompts.

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.

prompt_default_no

This will ask a yes/no question to the user, defaulting to no.

prompt_default_yes

This will ask a yes/no question to the user, defaulting to yes.

want_pureperl

This returns true if the user has indicated they want a pure-perl build.

want_compiled

This returns true if the user has explicitly indicated they do not want a pure-perl build.

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.

cpanm CPAN::Requirements::Dynamic

perl -MCPAN -e shell
install CPAN::Requirements::Dynamic