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NAME

       CPAN::Meta::History::Meta_1_4 - Version 1.4 metadata specification for META.yml

PREFACE

       This is a historical copy of the version 1.4 specification for META.yml files, copyright
       by Ken Williams and licensed under the same terms as Perl itself.

       Modifications from the original:

       •   Various spelling corrections

       •   Include list of valid licenses from Module::Build 0.2807 rather than linking to the
           module, with minor updates to text and links to reflect versions at the time of
           publication.

       •   Fixed some dead links to point to active resources.

SYNOPSIS

        --- #YAML:1.0
        name: Module-Build
        abstract: Build and install Perl modules
        version: 0.20
        author:
          - Ken Williams <kwilliams@cpan.org>
        license: perl
        distribution_type: module
        requires:
          Config: 0
          Cwd: 0
          Data::Dumper: 0
          ExtUtils::Install: 0
          File::Basename: 0
          File::Compare: 0
          File::Copy: 0
          File::Find: 0
          File::Path: 0
          File::Spec: 0
          IO::File: 0
          perl: 5.005_03
        recommends:
          Archive::Tar: 1.00
          ExtUtils::Install: 0.3
          ExtUtils::ParseXS: 2.02
          Pod::Text: 0
          YAML: 0.35
        build_requires:
          Test: 0
        resources:
          license: http://dev.perl.org/licenses/
        meta-spec:
          version: 1.4
          url: http://module-build.sourceforge.net/META-spec-v1.3.html
        generated_by: Module::Build version 0.20

DESCRIPTION

       This document describes version 1.4 of the META.yml specification.

       The META.yml file describes important properties of contributed Perl distributions such as
       the ones found on CPAN.  It is typically created by tools like Module::Build,
       Module::Install, and ExtUtils::MakeMaker.

       The fields in the META.yml file are meant to be helpful for people maintaining module
       collections (like CPAN), for people writing installation tools (like CPAN.pm or CPANPLUS),
       or just for people who want to know some stuff about a distribution before downloading it
       and starting to install it.

       Note: The latest stable version of this specification can always be found at
       <http://module-build.sourceforge.net/META-spec-current.html>, and the latest development
       version (which may include things that won't make it into the stable version) can always
       be found at <http://module-build.sourceforge.net/META-spec-blead.html>.

FORMAT

       META.yml files are written in the YAML format (see <http://www.yaml.org/>).

       See the following links to learn why we chose YAML instead of, say, XML or Data::Dumper:

       •   Module::Build design plans
           <http://www.nntp.perl.org/group/perl.makemaker/2002/04/msg407.html>

       •   Not keen on YAML <http://www.nntp.perl.org/group/perl.module-
           authors/2003/11/msg1353.html>

       •   META Concerns <http://www.nntp.perl.org/group/perl.module-
           authors/2003/11/msg1385.html>

TERMINOLOGY

       distribution
           This is the primary object described by the META.yml specification. 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".

       module
           This refers to a reusable library of code typically contained in a single file.
           Currently, we primarily talk of perl modules, but this specification should be open
           enough to apply to other languages as well (ex. python, ruby).  Examples of modules
           are "Class::Container", "LWP::Simple", or "DBD::File".

HEADER

       The first line of a META.yml file should be a valid YAML document header like "---
       #YAML:1.0".

FIELDS

       The rest of the META.yml file is one big YAML mapping whose keys are described here.

   meta-spec
       Example:

        meta-spec:
          version: 1.4
          url: http://module-build.sourceforge.net/META-spec-v1.3.html

       (Spec 1.1) [required] {URL} This field indicates the location of the version of the
       META.yml specification used.

   name
       Example:

         name: Module-Build

       (Spec 1.0) [required] {string} The name of the distribution which is often created by
       taking the "main module" in the distribution and changing "::" to "-".  Sometimes it's
       completely different, however, as in the case of the libwww-perl distribution (see
       <http://search.cpan.org/dist/libwww-perl/>).

   version
       Example:

         version: 0.20

       (Spec 1.0) [required] {version} The version of the distribution to which the META.yml file
       refers.

   abstract
       Example:

         abstract: Build and install Perl modules.

       (Spec 1.1) [required] {string} A short description of the purpose of the distribution.

   author
       Example:

         author:
           - Ken Williams <kwilliams@cpan.org>

       (Spec 1.1) [required] {list of strings} A YAML sequence indicating the author(s) of the
       distribution. The preferred form is author-name <email-address>.

   license
       Example:

         license: perl

       (Spec 1.0) [required] {string} The license under which this distribution may be used and
       redistributed.

       Must be one of the following licenses:

       apache
           The distribution is licensed under the Apache Software License version 1.1
           (<http://opensource.org/licenses/Apache-1.1>).

       artistic
           The distribution is licensed under the Artistic License version 1, as specified by the
           Artistic file in the standard perl distribution
           (<http://opensource.org/licenses/Artistic-Perl-1.0>).

       bsd The distribution is licensed under the BSD 3-Clause License
           (<http://opensource.org/licenses/BSD-3-Clause>).

       gpl The distribution is distributed under the terms of the GNU General Public License
           version 2 (<http://opensource.org/licenses/GPL-2.0>).

       lgpl
           The distribution is distributed under the terms of the GNU Lesser General Public
           License version 2 (<http://opensource.org/licenses/LGPL-2.1>).

       mit The distribution is licensed under the MIT License
           (<http://opensource.org/licenses/MIT>).

       mozilla
           The distribution is licensed under the Mozilla Public License.
           (<http://opensource.org/licenses/MPL-1.0> or <http://opensource.org/licenses/MPL-1.1>)

       open_source
           The distribution is licensed under some other Open Source Initiative-approved license
           listed at <http://www.opensource.org/licenses/>.

       perl
           The distribution may be copied and redistributed under the same terms as perl itself
           (this is by far the most common licensing option for modules on CPAN).  This is a dual
           license, in which the user may choose between either the GPL or the Artistic license.

       restrictive
           The distribution may not be redistributed without special permission from the author
           and/or copyright holder.

       unrestricted
           The distribution is licensed under a license that is not approved by
           www.opensource.org <http://www.opensource.org/> but that allows distribution without
           restrictions.

   distribution_type
       Example:

         distribution_type: module

       (Spec 1.0) [optional] {string} What kind of stuff is contained in this distribution.  Most
       things on CPAN are "module"s (which can also mean a collection of modules), but some
       things are "script"s.

       Unfortunately this field is basically meaningless, since many distributions are hybrids of
       several kinds of things, or some new thing, or subjectively different in focus depending
       on who's using them.  Tools like Module::Build and MakeMaker will likely stop generating
       this field.

   requires
       Example:

         requires:
           Data::Dumper: 0
           File::Find: 1.03

       (Spec 1.0) [optional] {map} A YAML mapping indicating the Perl prerequisites this
       distribution requires for proper operation.  The keys are the names of the prerequisites
       (module names or 'perl'), and the values are version specifications as described in
       VERSION SPECIFICATIONS.

   recommends
       Example:

         recommends:
           Data::Dumper: 0
           File::Find: 1.03

       (Spec 1.0) [optional] {map} A YAML mapping indicating the Perl prerequisites this
       distribution recommends for enhanced operation.  The keys are the names of the
       prerequisites (module names or 'perl'), and the values are version specifications as
       described in VERSION SPECIFICATIONS.

       ALTERNATIVE: It may be desirable to present to the user which features depend on which
       modules so they can make an informed decision about which recommended modules to install.

       Example:

         optional_features:
           foo:
             description: Provides the ability to blah.
             requires:
               Data::Dumper: 0
               File::Find: 1.03

       (Spec 1.1) [optional] {map} A YAML mapping of names for optional features which are made
       available when its requirements are met. For each feature a description is provided along
       with any of "requires", "build_requires", and "conflicts", which have the same meaning in
       this subcontext as described elsewhere in this document.

   build_requires
       Example:

         build_requires:
           Data::Dumper: 0
           File::Find: 1.03

       (Spec 1.0) [optional] {map} A YAML mapping indicating the Perl prerequisites required for
       building and/or testing of this distribution.  The keys are the names of the prerequisites
       (module names or 'perl'), and the values are version specifications as described in
       "VERSION SPECIFICATIONS".  These dependencies are not required after the distribution is
       installed.

   configure_requires
       Example:

         configure_requires:
           Module::Build: 0.2809
           Data::Dumper: 0
           File::Find: 1.03

       (Spec 1.4) [optional] {map} A YAML mapping indicating the Perl prerequisites required
       before configuring this distribution.  The keys are the names of the prerequisites (module
       names or 'perl'), and the values are version specifications as described in "VERSION
       SPECIFICATIONS".  These dependencies are not required after the distribution is installed.

   conflicts
       Example:

         conflicts:
           Data::Dumper: 0
           File::Find: 1.03

       (Spec 1.0) [optional] {map} A YAML mapping indicating any items that cannot be installed
       while this distribution is installed.  This is a pretty uncommon situation.  The keys for
       "conflicts" are the item names (module names or 'perl'), and the values are version
       specifications as described in "VERSION SPECIFICATIONS".

   dynamic_config
       Example:

         dynamic_config: 0

       (Spec 1.0) [optional] {boolean} A boolean flag indicating whether a Build.PL or
       Makefile.PL (or similar) must be executed when building this distribution, or whether it
       can be built, tested and installed solely from consulting its metadata file.  The main
       reason to set this to a true value is that your module performs some dynamic configuration
       (asking questions, sensing the environment, etc.) as part of its build/install process.

       Currently Module::Build doesn't actually do anything with this flag - it's probably going
       to be up to higher-level tools like CPAN to do something useful with it.  It can
       potentially bring lots of security, packaging, and convenience improvements.

       If this field is omitted, it defaults to 1 (true).

   private
       (Deprecated) (Spec 1.0) [optional] {map} This field has been renamed to "no_index".  See
       below.

   provides
       Example:

         provides:
           Foo::Bar:
             file: lib/Foo/Bar.pm
             version: 0.27_02
           Foo::Bar::Blah:
             file: lib/Foo/Bar/Blah.pm
           Foo::Bar::Baz:
             file: lib/Foo/Bar/Baz.pm
             version: 0.3

       (Spec 1.1) [optional] {map} A YAML mapping that describes all packages provided by this
       distribution.  This information can be (and, in some cases, is) used by distribution and
       automation mechanisms like PAUSE, CPAN, and search.cpan.org to build indexes saying in
       which distribution various packages can be found.

       When using tools like Module::Build that can generate the "provides" mapping for your
       distribution automatically, make sure you examine what it generates to make sure it makes
       sense - indexers will usually trust the "provides" field if it's present, rather than
       scanning through the distribution files themselves to figure out packages and versions.
       This is a good thing, because it means you can use the "provides" field to tell the
       indexers precisely what you want indexed about your distribution, rather than relying on
       them to essentially guess what you want indexed.

   no_index
       Example:

         no_index:
           file:
           - My/Module.pm
           directory:
           - My/Private
           package:
           - My::Module::Stuff
           namespace:
           - My::Module::Stuff

       (Spec 1.1) [optional] {map} A YAML mapping that describes any files, directories,
       packages, and namespaces that are private (i.e. implementation artifacts) that are not of
       interest to searching and indexing tools.  This is useful when no "provides" field is
       present.

       For example, <http://search.cpan.org/> excludes items listed in "no_index" when searching
       for POD, meaning files in these directories will not converted to HTML and made public -
       which is useful if you have example or test PODs that you don't want the search engine to
       go through.

       file

       (Spec 1.1) [optional] Exclude any listed file(s).

       directory

       (Spec 1.1) [optional] Exclude anything below the listed directory(ies).

       [Note: previous editions of the spec had "dir" instead of "directory", but I think
       MakeMaker and various users started using "directory", so in deference we switched to
       that.]

       package

       (Spec 1.1) [optional] Exclude the listed package(s).

       namespace

       (Spec 1.1) [optional] Excludes anything below the listed namespace(s), but not the listed
       namespace(s) its self.

   keywords
       Example:

         keywords:
           - make
           - build
           - install

       (Spec 1.1) [optional] {list} A sequence of keywords/phrases that describe this
       distribution.

   resources
       Example:

         resources:
           license: http://dev.perl.org/licenses/
           homepage: http://sourceforge.net/projects/module-build
           bugtracker: http://rt.cpan.org/NoAuth/Bugs.html?Dist=Module-Build
           repository: http://sourceforge.net/cvs/?group_id=45731
           MailingList: http://lists.sourceforge.net/lists/listinfo/module-build-general

       (Spec 1.1) [optional] {map} A mapping of any URL resources related to this distribution.
       All-lower-case keys, such as "homepage", "license", and "bugtracker", are reserved by this
       specification, as they have "official" meanings defined here in this specification.  If
       you'd like to add your own "special" entries (like the "MailingList" entry above), use at
       least one upper-case letter.

       The current set of official keys is:

       homepage
         The official home of this project on the web.

       license
         An URL for an official statement of this distribution's license.

       bugtracker
         An URL for a bug tracker (e.g. Bugzilla or RT queue) for this project.

   generated_by
       Example:

         generated_by: Module::Build version 0.20

       (Spec 1.0) [required] {string} Indicates the tool that was used to create this META.yml
       file.  It's good form to include both the name of the tool and its version, but this field
       is essentially opaque, at least for the moment. If META.yml was generated by hand, it is
       suggested that the author be specified here.

       [Note: My meta_stats.pl script which I use to gather statistics regarding META.yml usage
       prefers the form listed above, i.e. it splits on /\s+version\s+/ taking the first field as
       the name of the tool that generated the file and the second field as version of that tool.
       RWS]

VERSION SPECIFICATIONS

       Some fields require a version specification (ex. "requires", "recommends",
       "build_requires", etc.) to indicate the particular version(s) of some other module that
       may be required as a prerequisite.  This section details the version specification formats
       that are currently supported.

       The simplest format for a version specification 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.

       You may also 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.

SEE ALSO

       CPAN <http://www.cpan.org/>

       CPAN.pm

       CPANPLUS

       Data::Dumper

       ExtUtils::MakeMaker

       Module::Build

       Module::Install

       XML <http://www.w3.org/XML/>

       YAML <http://www.yaml.org/>

HISTORY

       March 14, 2003 (Pi day)
           • Created version 1.0 of this document.

       May 8, 2003
           • Added the "dynamic_config" field, which was missing from the initial version.

       November 13, 2003
           • Added more YAML rationale articles.

           • Fixed existing link to YAML discussion thread to point to new
             <http://nntp.x.perl.org/group/> site.

           • Added and deprecated the "private" field.

           • Added "abstract", "configure", "requires_packages", "requires_os", "excludes_os",
             and "no_index" fields.

           • Bumped version.

       November 16, 2003
           • Added "generation", "authored_by" fields.

           • Add alternative proposal to the "recommends" field.

           • Add proposal for a "requires_build_tools" field.

       December 9, 2003
           • Added link to latest version of this specification on CPAN.

           • Added section "VERSION SPECIFICATIONS".

           • Chang name from Module::Build::META-spec to CPAN::META::Specification.

           • Add proposal for "auto_regenerate" field.

       December 15, 2003
           • Add "index" field as a compliment to "no_index"

           • Add "keywords" field as a means to aid searching distributions.

           • Add "TERMINOLOGY" section to explain certain terms that may be ambiguous.

       July 26, 2005
           • Removed a bunch of items (generation, requires_build_tools, requires_packages,
             configure, requires_os, excludes_os, auto_regenerate) that have never actually been
             supported, but were more like records of brainstorming.

           • Changed "authored_by" to "author", since that's always been what it's actually
             called in actual META.yml files.

           • Added the "==" operator to the list of supported version-checking operators.

           • Noted that the "distribution_type" field is basically meaningless, and shouldn't
             really be used.

           • Clarified "dynamic_config" a bit.

       August 23, 2005
           • Removed the name "CPAN::META::Specification", since that implies a module that
             doesn't actually exist.

       June 12, 2007
           • Added "configure_requires".