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CPAN::Meta::Spec(3perl)Perl Programmers Reference GuideCPAN::Meta::Spec(3perl)

       CPAN::Meta::Spec - specification for CPAN distribution metadata

       version 2.120921

	 my $distmeta = {
	   name => 'Module-Build',
	   abstract => 'Build and install Perl modules',
	   description =>  "Module::Build is a system for "
	     . "building, testing, and installing Perl modules. "
	     . "It is meant to ... blah blah blah ...",
	   version  => '0.36',
	   release_status => 'stable',
	   author   => [
	     'Ken Williams <>',
	     'Module-Build List <>', # additional contact
	   license  => [ 'perl_5' ],
	   prereqs => {
	     runtime => {
	       requires => {
		 'perl'	  => '5.006',
		 'ExtUtils::Install' => '0',
		 'File::Basename' => '0',
		 'File::Compare'  => '0',
		 'IO::File'   => '0',
	       recommends => {
		 'Archive::Tar' => '1.00',
		 'ExtUtils::Install' => '0.3',
		 'ExtUtils::ParseXS' => '2.02',
	     build => {
	       requires => {
		 'Test::More' => '0',
	   resources => {
	     license => [''],
	   optional_features => {
	     domination => {
	       description => 'Take over the world',
	       prereqs	   => {
		 develop => { requires => { 'Genius::Evil'     => '1.234' } },
		 runtime => { requires => { 'Machine::Weather' => '2.0'	  } },
	   dynamic_config => 1,
	   keywords => [ qw/ toolchain cpan dual-life / ],
	   'meta-spec' => {
	     version => '2',
	     url     => '',
	   generated_by => 'Module::Build version 0.36',

       This document describes version 2 of the CPAN distribution metadata
       specification, also known as the "CPAN Meta Spec".

       Revisions of this specification for typo corrections and prose
       clarifications may be issued as CPAN::Meta::Spec 2.x.  These revisions
       will never change semantics or add or remove specified behavior.

       Distribution metadata describe important properties of Perl
       distributions. Distribution building tools like Module::Build,
       Module::Install, ExtUtils::MakeMaker or Dist::Zilla should create a
       metadata file in accordance with this specification and include it with
       the distribution for use by automated tools that index, examine,
       package or install Perl distributions.

	   This is the primary object described by the metadata. In the
	   context of this document it usually refers to a collection of
	   modules, scripts, and/or documents that are distributed together
	   for other developers to use.	 Examples of distributions are
	   "Class-Container", "libwww-perl", or "DBI".

	   This refers to a reusable library of code contained in a single
	   file.  Modules usually contain one or more packages and are often
	   referred to by the name of a primary package that can be mapped to
	   the file name. For example, one might refer to "File::Spec" instead
	   of File/

	   This refers to a namespace declared with the Perl "package"
	   statement.  In Perl, packages often have a version number property
	   given by the $VERSION variable in the namespace.

	   This refers to code that reads a metadata file, deserializes it
	   into a data structure in memory, or interprets a data structure of
	   metadata elements.

	   This refers to code that constructs a metadata data structure,
	   serializes into a bytestream and/or writes it to disk.

       must, should, may, etc.
	   These terms are interpreted as described in IETF RFC 2119.

       Fields in the "STRUCTURE" section describe data elements, each of which
       has an associated data type as described herein.	 There are four
       primitive types: Boolean, String, List and Map.	Other types are
       subtypes of primitives and define compound data structures or define
       constraints on the values of a data element.

       A Boolean is used to provide a true or false value.  It must be
       represented as a defined value.

       A String is data element containing a non-zero length sequence of
       Unicode characters, such as an ordinary Perl scalar that is not a

       A List is an ordered collection of zero or more data elements.
       Elements of a List may be of mixed types.

       Producers must represent List elements using a data structure which
       unambiguously indicates that multiple values are possible, such as a
       reference to a Perl array (an "arrayref").

       Consumers expecting a List must consider a String as equivalent to a
       List of length 1.

       A Map is an unordered collection of zero or more data elements
       ("values"), indexed by associated String elements ("keys").  The Map's
       value elements may be of mixed types.

   License String
       A License String is a subtype of String with a restricted set of
       values.	Valid values are described in detail in the description of the
       "license" field.

       URL is a subtype of String containing a Uniform Resource Locator or
       Identifier.  [ This type is called URL and not URI for historical
       reasons. ]

       A Version is a subtype of String containing a value that describes the
       version number of packages or distributions.  Restrictions on format
       are described in detail in the "Version Formats" section.

   Version Range
       The Version Range type is a subtype of String.  It describes a range of
       Versions that may be present or installed to fulfill prerequisites.  It
       is specified in detail in the "Version Ranges" section.

       The metadata structure is a data element of type Map.  This section
       describes valid keys within the Map.

       Any keys not described in this specification document (whether top-
       level or within compound data structures described herein) are
       considered custom keys and must begin with an "x" or "X" and be
       followed by an underscore; i.e. they must match the pattern:
       "qr{\Ax_}i".  If a custom key refers to a compound data structure,
       subkeys within it do not need an "x_" or "X_" prefix.

       Consumers of metadata may ignore any or all custom keys.	 All other
       keys not described herein are invalid and should be ignored by
       consumers.  Producers must not generate or output invalid keys.

       For each key, an example is provided followed by a description.	The
       description begins with the version of spec in which the key was added
       or in which the definition was modified, whether the key is required or
       optional and the data type of the corresponding data element.  These
       items are in parentheses, brackets and braces, respectively.

       If a data type is a Map or Map subtype, valid subkeys will be described
       as well.

       Some fields are marked Deprecated.  These are shown for historical
       context and must not be produced in or consumed from any metadata
       structure of version 2 or higher.



	 abstract => 'Build and install Perl modules'

       (Spec 1.2) [required] {String}

       This is a short description of the purpose of the distribution.



	 author => [ 'Ken Williams <>' ]

       (Spec 1.2) [required] {List of one or more Strings}

       This List indicates the person(s) to contact concerning the
       distribution. The preferred form of the contact string is:

	 contact-name <email-address>

       This field provides a general contact list independent of other
       structured fields provided within the "resources" field, such as
       "bugtracker".  The addressee(s) can be contacted for any purpose
       including but not limited to (security) problems with the distribution,
       questions about the distribution or bugs in the distribution.

       A distribution's original author is usually the contact listed within
       this field.  Co-maintainers, successor maintainers or mailing lists
       devoted to the distribution may also be listed in addition to or
       instead of the original author.



	 dynamic_config => 1

       (Spec 2) [required] {Boolean}

       A boolean flag indicating whether a Build.PL or Makefile.PL (or
       similar) must be executed to determine prerequisites.

       This field should be set to a true value if the distribution performs
       some dynamic configuration (asking questions, sensing the environment,
       etc.) as part of its configuration.  This field should be set to a
       false value to indicate that prerequisites included in metadata may be
       considered final and valid for static analysis.

       This field explicitly does not indicate whether installation may be
       safely performed without using a Makefile or Build file, as there may
       be special files to install or custom installation targets (e.g. for
       dual-life modules that exist on CPAN as well as in the Perl core).
       This field only defines whether prerequisites are complete as given in
       the metadata.



	 generated_by => 'Module::Build version 0.36'

       (Spec 1.0) [required] {String}

       This field indicates the tool that was used to create this metadata.
       There are no defined semantics for this field, but it is traditional to
       use a string in the form "Generating::Package version 1.23" or the
       author's name, if the file was generated by hand.



	 license => [ 'perl_5' ]

	 license => [ 'apache_2', 'mozilla_1_0' ]

       (Spec 2) [required] {List of one or more License Strings}

       One or more licenses that apply to some or all of the files in the
       distribution.  If multiple licenses are listed, the distribution
       documentation should be consulted to clarify the interpretation of
       multiple licenses.

       The following list of license strings are valid:

	string		description
	-------------	-----------------------------------------------
	agpl_3		GNU Affero General Public License, Version 3
	apache_1_1	Apache Software License, Version 1.1
	apache_2_0	Apache License, Version 2.0
	artistic_1	Artistic License, (Version 1)
	artistic_2	Artistic License, Version 2.0
	bsd		BSD License (three-clause)
	freebsd		FreeBSD License (two-clause)
	gfdl_1_2	GNU Free Documentation License, Version 1.2
	gfdl_1_3	GNU Free Documentation License, Version 1.3
	gpl_1		GNU General Public License, Version 1
	gpl_2		GNU General Public License, Version 2
	gpl_3		GNU General Public License, Version 3
	lgpl_2_1	GNU Lesser General Public License, Version 2.1
	lgpl_3_0	GNU Lesser General Public License, Version 3.0
	mit		MIT (aka X11) License
	mozilla_1_0	Mozilla Public License, Version 1.0
	mozilla_1_1	Mozilla Public License, Version 1.1
	openssl		OpenSSL License
	perl_5		The Perl 5 License (Artistic 1 & GPL 1 or later)
	qpl_1_0		Q Public License, Version 1.0
	ssleay		Original SSLeay License
	sun		Sun Internet Standards Source License (SISSL)
	zlib		zlib License

       The following license strings are also valid and indicate other
       licensing not described above:

	string		description
	-------------	-----------------------------------------------
	open_source	Other Open Source Initiative (OSI) approved license
	restricted	Requires special permission from copyright holder
	unrestricted	Not an OSI approved license, but not restricted
	unknown		License not provided in metadata

       All other strings are invalid in the license field.



	 'meta-spec' => {
	   version => '2',
	   url	   => '',

       (Spec 1.2) [required] {Map}

       This field indicates the version of the CPAN Meta Spec that should be
       used to interpret the metadata.	Consumers must check this key as soon
       as possible and abort further metadata processing if the meta-spec
       version is not supported by the consumer.

       The following keys are valid, but only "version" is required.

	   This subkey gives the integer Version of the CPAN Meta Spec against
	   which the document was generated.

       url This is a URL of the metadata specification document corresponding
	   to the given version.  This is strictly for human-consumption and
	   should not impact the interpretation of the document.



	 name => 'Module-Build'

       (Spec 1.0) [required] {String}

       This field is the name of the distribution.  This is often created by
       taking the "main package" in the distribution and changing "::" to "-",
       but the name may be completely unrelated to the packages within the
       distribution.  C.f. <>.



	 release_status => 'stable'

       (Spec 2) [required] {String}

       This field provides the	release status of this distribution.  If the
       "version" field contains an underscore character, then "release_status"
       must not be "stable."

       The "release_status" field must have one of the following values:

	   This indicates an ordinary, "final" release that should be indexed
	   by PAUSE or other indexers.

	   This indicates a "beta" release that is substantially complete, but
	   has an elevated risk of bugs and requires additional testing.  The
	   distribution should not be installed over a stable release without
	   an explicit request or other confirmation from a user.  This
	   release status may also be used for "release candidate" versions of
	   a distribution.

	   This indicates an "alpha" release that is under active development,
	   but has been released for early feedback or testing and may be
	   missing features or may have serious bugs.  The distribution should
	   not be installed over a stable release without an explicit request
	   or other confirmation from a user.

       Consumers may use this field to determine how to index the distribution
       for CPAN or other repositories in addition to or in replacement of
       heuristics based on version number or file name.



	 version => '0.36'

       (Spec 1.0) [required] {Version}

       This field gives the version of the distribution to which the metadata
       structure refers.



	   description =>  "Module::Build is a system for "
	     . "building, testing, and installing Perl modules. "
	     . "It is meant to ... blah blah blah ...",

       (Spec 2) [optional] {String}

       A longer, more complete description of the purpose or intended use of
       the distribution than the one provided by the "abstract" key.



	 keywords => [ qw/ toolchain cpan dual-life / ]

       (Spec 1.1) [optional] {List of zero or more Strings}

       A List of keywords that describe this distribution.  Keywords must not
       include whitespace.



	 no_index => {
	   file	     => [ 'My/' ],
	   directory => [ 'My/Private' ],
	   package   => [ 'My::Module::Secret' ],
	   namespace => [ 'My::Module::Sample' ],

       (Spec 1.2) [optional] {Map}

       This Map describes any files, directories, packages, and namespaces
       that are private to the packaging or implementation of the distribution
       and should be ignored by indexing or search tools.

       Valid subkeys are as follows:

	   A List of relative paths to files.  Paths must be specified with
	   unix conventions.

	   A List of relative paths to directories.  Paths must be specified
	   with unix conventions.

	   [ Note: previous editions of the spec had "dir" instead of
	   "directory" ]

	   A List of package names.

	   A List of package namespaces, where anything below the namespace
	   must be ignored, but not the namespace itself.

	   In the example above for "no_index", "My::Module::Sample::Foo"
	   would be ignored, but "My::Module::Sample" would not.



	 optional_features => {
	   sqlite => {
	     description => 'Provides SQLite support',
	     prereqs => {
	       runtime => {
		 requires => {
		   'DBD::SQLite' => '1.25'

       (Spec 2) [optional] {Map}

       This Map describes optional features with incremental prerequisites.
       Each key of the "optional_features" Map is a String used to identify
       the feature and each value is a Map with additional information about
       the feature.  Valid subkeys include:

	   This is a String describing the feature.  Every optional feature
	   should provide a description

	   This entry is required and has the same structure as that of the
	   "prereqs" key.  It provides a list of package requirements that
	   must be satisfied for the feature to be supported or enabled.

	   There is one crucial restriction:  the prereqs of an optional
	   feature must not include "configure" phase prereqs.

       Consumers must not include optional features as prerequisites without
       explicit instruction from users (whether via interactive prompting, a
       function parameter or a configuration value, etc. ).

       If an optional feature is used by a consumer to add additional
       prerequisites, the consumer should merge the optional feature
       prerequisites into those given by the "prereqs" key using the same
       semantics.  See "Merging and Resolving Prerequisites" for details on
       merging prerequisites.

       Suggestion for disuse: Because there is currently no way for a
       distribution to specify a dependency on an optional feature of another
       dependency, the use of "optional_feature" is discouraged.  Instead,
       create a separate, installable distribution that ensures the desired
       feature is available.  For example, if "Foo::Bar" has a "Baz" feature,
       release a separate "Foo-Bar-Baz" distribution that satisfies
       requirements for the feature.



	 prereqs => {
	   runtime => {
	     requires => {
	       'perl'	       => '5.006',
	       'File::Spec'    => '0.86',
	       'JSON'	       => '2.16',
	     recommends => {
	       'JSON::XS'      => '2.26',
	     suggests => {
	       'Archive::Tar'  => '0',
	   build => {
	     requires => {
	       'Alien::SDL'    => '1.00',
	   test => {
	     recommends => {
	       'Test::Deep'    => '0.10',

       (Spec 2) [optional] {Map}

       This is a Map that describes all the prerequisites of the distribution.
       The keys are phases of activity, such as "configure", "build", "test"
       or "runtime".  Values are Maps in which the keys name the type of
       prerequisite relationship such as "requires", "recommends", or
       "suggests" and the value provides a set of prerequisite relations.  The
       set of relations must be specified as a Map of package names to version

       The full definition for this field is given in the "Prereq Spec"



	 provides => {
	   'Foo::Bar' => {
	     file    => 'lib/Foo/',
	     version => 0.27_02
	   'Foo::Bar::Blah' => {
	     file    => 'lib/Foo/Bar/',
	   'Foo::Bar::Baz' => {
	     file    => 'lib/Foo/Bar/',
	     version => 0.3,

       (Spec 1.2) [optional] {Map}

       This describes all packages provided by this distribution.  This
       information is used by distribution and automation mechanisms like
       PAUSE, CPAN, and to build indexes saying in which
       distribution various packages can be found.

       The keys of "provides" are package names that can be found within the
       distribution.  The values are Maps with the following valid subkeys:

	   This field is required.  The value must contain a Unix-style
	   relative file path from the root of the distribution to the module
	   containing the package.

	   This field contains a Version String for the package, if one



	 resources => {
	   license     => [ '' ],
	   homepage    => '',
	   bugtracker  => {
	     web    => '',
	     mailto => '',
	   repository  => {
	     url  => 'git://',
	     web  => '',
	     type => 'git',
	   x_twitter   => '',

       (Spec 2) [optional] {Map}

       This field describes resources related to this distribution.

       Valid subkeys include:

	   The official home of this project on the web.

	   A List of URL's that relate to this distribution's license.	As
	   with the top-level "license" field, distribution documentation
	   should be consulted to clarify the interpretation of multiple
	   licenses provided here.

	   This entry describes the bug tracking system for this distribution.
	   It is a Map with the following valid keys:

	     web    - a URL pointing to a web front-end for the bug tracker
	     mailto - an email address to which bugs can be sent

	   This entry describes the source control repository for this
	   distribution.  It is a Map with the following valid keys:

	     url  - a URL pointing to the repository itself
	     web  - a URL pointing to a web front-end for the repository
	     type - a lowercase string indicating the VCS used

	   Because a url like "" is ambiguous as to
	   type, producers should provide a "type" whenever a "url" key is
	   given.  The "type" field should be the name of the most common
	   program used to work with the repository, e.g. git, svn, cvs,
	   darcs, bzr or hg.


       (Deprecated in Spec 2) [optional] {String}

       Replaced by "prereqs"


       (Deprecated in Spec 2) [optional] {String}

       Replaced by "prereqs"


       (Deprecated in Spec 2) [optional] {String}

       Replaced by "prereqs"


       (Deprecated in Spec 2) [optional] {String}

       This field indicated 'module' or 'script' but was considered
       meaningless, since many distributions are hybrids of several kinds of


       (Deprecated in Spec 1.2) [optional] {URL}

       Replaced by "license" in "resources"


       (Deprecated in Spec 1.2) [optional] {Map}

       This field has been renamed to "no_index".


       (Deprecated in Spec 2) [optional] {String}

       Replaced by "prereqs"


       (Deprecated in Spec 2) [optional] {String}

       Replaced by "prereqs"

   Version Formats
       This section defines the Version type, used by several fields in the
       CPAN Meta Spec.

       Version numbers must be treated as strings, not numbers.	 For example,
       1.200 must not be serialized as 1.2.  Version comparison should be
       delegated to the Perl version module, version 0.80 or newer.

       Unless otherwise specified, version numbers must appear in one of two

       Decimal versions
	   Decimal versions are regular "decimal numbers", with some
	   limitations.	 They must be non-negative and must begin and end with
	   a digit.  A single underscore may be included, but must be between
	   two digits.	They must not use exponential notation ("1.23e-2").

	      version => '1.234'       # OK
	      version => '1.23_04'     # OK

	      version => '1.23_04_05'  # Illegal
	      version => '1.'	       # Illegal
	      version => '.1'	       # Illegal

       Dotted-integer versions
	   Dotted-integer (also known as dotted-decimal) versions consist of
	   positive integers separated by full stop characters (i.e. "dots",
	   "periods" or "decimal points").  This are equivalent in format to
	   Perl "v-strings", with some additional restrictions on form.	 They
	   must be given in "normal" form, which has a leading "v" character
	   and at least three integer components.  To retain a one-to-one
	   mapping with decimal versions, all components after the first
	   should be restricted to the range 0 to 999.	The final component
	   may be separated by an underscore character instead of a period.

	      version => 'v1.2.3'      # OK
	      version => 'v1.2_3'      # OK
	      version => 'v1.2.3.4'    # OK
	      version => 'v1.2.3_4'    # OK
	      version => 'v2009.10.31' # OK

	      version => 'v1.2'		 # Illegal
	      version => '1.2.3'	 # Illegal
	      version => 'v1.2_3_4'	 # Illegal
	      version => 'v1.2009.10.31' # Not recommended

   Version Ranges
       Some fields (prereq, optional_features) indicate the particular
       version(s) of some other module that may be required as a prerequisite.
       This section details the Version Range type used to provide this

       The simplest format for a Version Range is just the version number
       itself, e.g. 2.4.  This means that at least version 2.4 must be
       present.	 To indicate that any version of a prerequisite is okay, even
       if the prerequisite doesn't define a version at all, use the version 0.

       Alternatively, a version range may use the operators < (less than), <=
       (less than or equal), > (greater than), >= (greater than or equal), ==
       (equal), and != (not equal).  For example, the specification "< 2.0"
       means that any version of the prerequisite less than 2.0 is suitable.

       For more complicated situations, version specifications may be AND-ed
       together using commas.  The specification ">= 1.2, != 1.5, < 2.0"
       indicates a version that must be at least 1.2, less than 2.0, and not
       equal to 1.5.

   Prereq Spec
       The "prereqs" key in the top-level metadata and within
       "optional_features" define the relationship between a distribution and
       other packages.	The prereq spec structure is a hierarchical data
       structure which divides prerequisites into Phases of activity in the
       installation process and Relationships that indicate how prerequisites
       should be resolved.

       For example, to specify that "Data::Dumper" is "required" during the
       "test" phase, this entry would appear in the distribution metadata:

	 prereqs => {
	   test => {
	     requires => {
	       'Data::Dumper' => '2.00'


       Requirements for regular use must be listed in the "runtime" phase.
       Other requirements should be listed in the earliest stage in which they
       are required and consumers must accumulate and satisfy requirements
       across phases before executing the activity. For example, "build"
       requirements must also be available during the "test" phase.

	 before action	     requirements that must be met
	 ----------------    --------------------------------
	 perl Build.PL	     configure
	 perl Makefile.PL

	 make		     configure, runtime, build

	 make test	     configure, runtime, build, test
	 Build test

       Consumers that install the distribution must ensure that runtime
       requirements are also installed and may install dependencies from other

	 after action	     requirements that must be met
	 ----------------    --------------------------------
	 make install	     runtime
	 Build install

	   The configure phase occurs before any dynamic configuration has
	   been attempted.  Libraries required by the configure phase must be
	   available for use before the distribution building tool has been

	   The build phase is when the distribution's source code is compiled
	   (if necessary) and otherwise made ready for installation.

	   The test phase is when the distribution's automated test suite is
	   run.	 Any library that is needed only for testing and not for
	   subsequent use should be listed here.

	   The runtime phase refers not only to when the distribution's
	   contents are installed, but also to its continued use.  Any library
	   that is a prerequisite for regular use of this distribution should
	   be indicated here.

	   The develop phase's prereqs are libraries needed to work on the
	   distribution's source code as its author does.  These tools might
	   be needed to build a release tarball, to run author-only tests, or
	   to perform other tasks related to developing new versions of the


	   These dependencies must be installed for proper completion of the

	   Recommended dependencies are strongly encouraged and should be
	   satisfied except in resource constrained environments.

	   These dependencies are optional, but are suggested for enhanced
	   operation of the described distribution.

	   These libraries cannot be installed when the phase is in operation.
	   This is a very rare situation, and the "conflicts" relationship
	   should be used with great caution, or not at all.

   Merging and Resolving Prerequisites
       Whenever metadata consumers merge prerequisites, either from different
       phases or from "optional_features", they should merged in a way which
       preserves the intended semantics of the prerequisite structure.
       Generally, this means concatenating the version specifications using
       commas, as described in the "Version Ranges" section.

       Another subtle error that can occur in resolving prerequisites comes
       from the way that modules in prerequisites are indexed to distribution
       files on CPAN.  When a module is deleted from a distribution,
       prerequisites calling for that module could indicate an older
       distribution should installed, potentially overwriting files from a
       newer distribution.

       For example, as of Oct 31, 2009, the CPAN index file contained these
       module-distribution mappings:

	 Class::MOP		      0.94  D/DR/DROLSKY/Class-MOP-0.94.tar.gz
	 Class::MOP::Class	      0.94  D/DR/DROLSKY/Class-MOP-0.94.tar.gz
	 Class::MOP::Class::Immutable 0.04  S/ST/STEVAN/Class-MOP-0.36.tar.gz

       Consider the case where "Class::MOP" 0.94 is installed.	If a
       distribution specified "Class::MOP::Class::Immutable" as a
       prerequisite, it could result in Class-MOP-0.36.tar.gz being installed,
       overwriting any files from Class-MOP-0.94.tar.gz.

       Consumers of metadata should test whether prerequisites would result in
       installed module files being "downgraded" to an older version and may
       warn users or ignore the prerequisite that would cause such a result.

       Distribution metadata should be serialized (as a hashref) as JSON-
       encoded data and packaged with distributions as the file META.json.

       In the past, the distribution metadata structure had been packed with
       distributions as META.yml, a file in the YAML Tiny format (for which,
       see YAML::Tiny).	 Tools that consume distribution metadata from disk
       should be capable of loading META.yml, but should prefer META.json if
       both are found.

   Extracting Version Numbers from Perl Modules
       To get the version number from a Perl module, consumers should use the
       "MM->parse_version($file)" method provided by ExtUtils::MakeMaker or
       Module::Metadata.  For example, for the module given by $mod, the
       version may be retrieved in one of the following ways:

	 # via ExtUtils::MakeMaker
	 my $file = MM->_installed_file_for_module($mod);
	 my $version = MM->parse_version($file)

       The private "_installed_file_for_module" method may be replaced with
       other methods for locating a module in @INC.

	 # via Module::Metadata
	 my $info = Module::Metadata->new_from_module($mod);
	 my $version = $info->version;

       If only a filename is available, the following approach may be used:

	 # via Module::Build
	 my $info = Module::Metadata->new_from_file($file);
	 my $version = $info->version;

   Comparing Version Numbers
       The version module provides the most reliable way to compare version
       numbers in all the various ways they might be provided or might exist
       within modules.	Given two strings containing version numbers, $v1 and
       $v2, they should be converted to "version" objects before using
       ordinary comparison operators.  For example:

	 use version;
	 if ( version->new($v1) <=> version->new($v2) ) {
	   print "Versions are not equal\n";

       If the only comparison needed is whether an installed module is of a
       sufficiently high version, a direct test may be done using the string
       form of "eval" and the "use" function.  For example, for module $mod
       and version prerequisite $prereq:

	 if ( eval "use $mod $prereq (); 1" ) {
	   print "Module $mod version is OK.\n";

       If the values of $mod and $prereq have not been scrubbed, however, this
       presents security implications.

       CPAN, <>, <>

       CPANPLUS, <>

       ExtUtils::MakeMaker, <>

       Module::Build, <>

       Module::Install, <>

       JSON, <>

       YAML, <>

       Ken Williams wrote the original CPAN Meta Spec (also known as the
       "META.yml spec") in 2003 and maintained it through several revisions
       with input from various members of the community.  In 2005, Randy Sims
       redrafted it from HTML to POD for the version 1.2 release.  Ken
       continued to maintain the spec through version 1.4.

       In late 2009, David Golden organized the version 2 proposal review
       process.	 David and Ricardo Signes drafted the final version 2 spec in
       April 2010 based on the version 1.4 spec and patches contributed during
       the proposal process.

       Several others have contributed patches over the years.	The full list
       of contributors in the repository history currently includes:

	 Avar Arnfjord Bjarmason
	 Christopher J. Madsen
	 Damyan Ivanov
	 David Golden
	 Eric Wilhelm
	 Ken Williams
	 Michael G. Schwern
	 Randy Sims
	 Ricardo Signes

       ·   David Golden <>

       ·   Ricardo Signes <>

       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.

perl v5.18.2			  2014-01-06	       CPAN::Meta::Spec(3perl)

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