NAME

       CPAN::Meta::Requirements - a set of version requirements for a CPAN dist

VERSION

       version 2.122

SYNOPSIS

         use CPAN::Meta::Requirements;

         my $build_requires = CPAN::Meta::Requirements->new;

         $build_requires->add_minimum('Library::Foo' => 1.208);

         $build_requires->add_minimum('Library::Foo' => 2.602);

         $build_requires->add_minimum('Module::Bar'  => 'v1.2.3');

         $METAyml->{build_requires} = $build_requires->as_string_hash;

DESCRIPTION

       A CPAN::Meta::Requirements object models a set of version constraints like those specified
       in the META.yml or META.json files in CPAN distributions.  It can be built up by adding
       more and more constraints, and it will reduce them to the simplest representation.

       Logically impossible constraints will be identified immediately by thrown exceptions.

METHODS

   new
         my $req = CPAN::Meta::Requirements->new;

       This returns a new CPAN::Meta::Requirements object.  It takes an optional hash reference
       argument.  The following keys are supported:

       •   <bad_version_hook> -- if provided, when a version cannot be parsed into

           a version object, this code reference will be called with the invalid version string
           as an argument.  It must return a valid version object.

       All other keys are ignored.

   add_minimum
         $req->add_minimum( $module => $version );

       This adds a new minimum version requirement.  If the new requirement is redundant to the
       existing specification, this has no effect.

       Minimum requirements are inclusive.  $version is required, along with any greater version
       number.

       This method returns the requirements object.

   add_maximum
         $req->add_maximum( $module => $version );

       This adds a new maximum version requirement.  If the new requirement is redundant to the
       existing specification, this has no effect.

       Maximum requirements are inclusive.  No version strictly greater than the given version is
       allowed.

       This method returns the requirements object.

   add_exclusion
         $req->add_exclusion( $module => $version );

       This adds a new excluded version.  For example, you might use these three method calls:

         $req->add_minimum( $module => '1.00' );
         $req->add_maximum( $module => '1.82' );

         $req->add_exclusion( $module => '1.75' );

       Any version between 1.00 and 1.82 inclusive would be acceptable, except for 1.75.

       This method returns the requirements object.

   exact_version
         $req->exact_version( $module => $version );

       This sets the version required for the given module to exactly the given version.  No
       other version would be considered acceptable.

       This method returns the requirements object.

   add_requirements
         $req->add_requirements( $another_req_object );

       This method adds all the requirements in the given CPAN::Meta::Requirements object to the
       requirements object on which it was called.  If there are any conflicts, an exception is
       thrown.

       This method returns the requirements object.

   accepts_module
         my $bool = $req->accepts_modules($module => $version);

       Given an module and version, this method returns true if the version specification for the
       module accepts the provided version.  In other words, given:

         Module => '>= 1.00, < 2.00'

       We will accept 1.00 and 1.75 but not 0.50 or 2.00.

       For modules that do not appear in the requirements, this method will return true.

   clear_requirement
         $req->clear_requirement( $module );

       This removes the requirement for a given module from the object.

       This method returns the requirements object.

   requirements_for_module
         $req->requirements_for_module( $module );

       This returns a string containing the version requirements for a given module in the format
       described in CPAN::Meta::Spec or undef if the given module has no requirements. This
       should only be used for informational purposes such as error messages and should not be
       interpreted or used for comparison (see "accepts_module" instead.)

   required_modules
       This method returns a list of all the modules for which requirements have been specified.

   clone
         $req->clone;

       This method returns a clone of the invocant.  The clone and the original object can then
       be changed independent of one another.

   is_simple
       This method returns true if and only if all requirements are inclusive minimums -- that
       is, if their string expression is just the version number.

   is_finalized
       This method returns true if the requirements have been finalized by having the "finalize"
       method called on them.

   finalize
       This method marks the requirements finalized.  Subsequent attempts to change the
       requirements will be fatal, if they would result in a change.  If they would not alter the
       requirements, they have no effect.

       If a finalized set of requirements is cloned, the cloned requirements are not also
       finalized.

   as_string_hash
       This returns a reference to a hash describing the requirements using the strings in the
       META.yml specification.

       For example after the following program:

         my $req = CPAN::Meta::Requirements->new;

         $req->add_minimum('CPAN::Meta::Requirements' => 0.102);

         $req->add_minimum('Library::Foo' => 1.208);

         $req->add_maximum('Library::Foo' => 2.602);

         $req->add_minimum('Module::Bar'  => 'v1.2.3');

         $req->add_exclusion('Module::Bar'  => 'v1.2.8');

         $req->exact_version('Xyzzy'  => '6.01');

         my $hashref = $req->as_string_hash;

       $hashref would contain:

         {
           'CPAN::Meta::Requirements' => '0.102',
           'Library::Foo' => '>= 1.208, <= 2.206',
           'Module::Bar'  => '>= v1.2.3, != v1.2.8',
           'Xyzzy'        => '== 6.01',
         }

   add_string_requirement
         $req->add_string_requirement('Library::Foo' => '>= 1.208, <= 2.206');

       This method parses the passed in string and adds the appropriate requirement for the given
       module.  It understands version ranges as described in the "Version Ranges" in
       CPAN::Meta::Spec. For example:

       1.3
       >= 1.3
       <= 1.3
       == 1.3
       != 1.3
       > 1.3
       < 1.3
       >= 1.3, != 1.5, <= 2.0
           A version number without an operator is equivalent to specifying a minimum (">=").
           Extra whitespace is allowed.

   from_string_hash
         my $req = CPAN::Meta::Requirements->from_string_hash( \%hash );

       This is an alternate constructor for a CPAN::Meta::Requirements object.  It takes a hash
       of module names and version requirement strings and returns a new CPAN::Meta::Requirements
       object.

SUPPORT

   Bugs / Feature Requests
       Please report any bugs or feature requests through the issue tracker at
       <http://rt.cpan.org/Public/Dist/Display.html?Name=CPAN-Meta-Requirements>.  You will be
       notified automatically of any progress on your issue.

   Source Code
       This is open source software.  The code repository is available for public review and
       contribution under the terms of the license.

       <https://github.com/dagolden/cpan-meta-requirements>

         git clone https://github.com/dagolden/cpan-meta-requirements.git

AUTHORS

       •   David Golden <dagolden@cpan.org>

       •   Ricardo Signes <rjbs@cpan.org>

COPYRIGHT AND LICENSE

       This software is copyright (c) 2010 by David Golden and Ricardo Signes.

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