Version::Requirements(3perl)				 Perl Programmers Reference Guide			      Version::Requirements(3perl)

NAME

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

VERSION

       version 0.101020

SYNOPSIS

	 use Version::Requirements;

	 my $build_requires = Version::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 Version::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 = Version::Requirements->new;

       This returns a new Version::Requirements object.  It ignores any arguments given.

   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 Version::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.

   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 = Version::Requirements->new;

	 $req->add_minimum('Version::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:

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

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

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

AUTHOR

	 Ricardo Signes <rjbs@cpan.org>

COPYRIGHT AND LICENSE

       This software is copyright (c) 2010 by 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.

perl v5.14.2							    2011-09-19					      Version::Requirements(3perl)