Edit File: Meta_1_4.pod
=for :stopwords MailingList PODs RWS subcontext =head1 NAME CPAN::Meta::History::Meta_1_4 - Version 1.4 metadata specification for META.yml =head1 PREFACE This is a historical copy of the version 1.4 specification for F<META.yml> files, copyright by Ken Williams and licensed under the same terms as Perl itself. Modifications from the original: =over =item * Various spelling corrections =item * Include list of valid licenses from L<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. =item * Fixed some dead links to point to active resources. =back =head1 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 =head1 DESCRIPTION This document describes version 1.4 of the F<META.yml> specification. The F<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 F<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. I<Note: The latest stable version of this specification can always be found at L<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 L<http://module-build.sourceforge.net/META-spec-blead.html>.> =head1 FORMAT F<META.yml> files are written in the YAML format (see L<http://www.yaml.org/>). See the following links to learn why we chose YAML instead of, say, XML or Data::Dumper: =over 4 =item * L<Module::Build design plans|http://www.nntp.perl.org/group/perl.makemaker/2002/04/msg407.html> =item * L<Not keen on YAML|http://www.nntp.perl.org/group/perl.module-authors/2003/11/msg1353.html> =item * L<META Concerns|http://www.nntp.perl.org/group/perl.module-authors/2003/11/msg1385.html> =back =head1 TERMINOLOGY =over 4 =item distribution This is the primary object described by the F<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 C<Class-Container>, C<libwww-perl>, or C<DBI>. =item 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 C<Class::Container>, C<LWP::Simple>, or C<DBD::File>. =back =head1 HEADER The first line of a F<META.yml> file should be a valid YAML document header like C<"--- #YAML:1.0">. =head1 FIELDS The rest of the F<META.yml> file is one big YAML mapping whose keys are described here. =head2 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. =head2 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 L<http://search.cpan.org/dist/libwww-perl/>). =head2 version Example: version: 0.20 (Spec 1.0) [required] {version} The version of the distribution to which the F<META.yml> file refers. =head2 abstract Example: abstract: Build and install Perl modules. (Spec 1.1) [required] {string} A short description of the purpose of the distribution. =head2 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>. =head2 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: =over 4 =item apache The distribution is licensed under the Apache Software License version 1.1 (L<http://opensource.org/licenses/Apache-1.1>). =item artistic The distribution is licensed under the Artistic License version 1, as specified by the Artistic file in the standard perl distribution (L<http://opensource.org/licenses/Artistic-Perl-1.0>). =item bsd The distribution is licensed under the BSD 3-Clause License (L<http://opensource.org/licenses/BSD-3-Clause>). =item gpl The distribution is distributed under the terms of the GNU General Public License version 2 (L<http://opensource.org/licenses/GPL-2.0>). =item lgpl The distribution is distributed under the terms of the GNU Lesser General Public License version 2 (L<http://opensource.org/licenses/LGPL-2.1>). =item mit The distribution is licensed under the MIT License (L<http://opensource.org/licenses/MIT>). =item mozilla The distribution is licensed under the Mozilla Public License. (L<http://opensource.org/licenses/MPL-1.0> or L<http://opensource.org/licenses/MPL-1.1>) =item open_source The distribution is licensed under some other Open Source Initiative-approved license listed at L<http://www.opensource.org/licenses/>. =item 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. =item restrictive The distribution may not be redistributed without special permission from the author and/or copyright holder. =item unrestricted The distribution is licensed under a license that is not approved by L<www.opensource.org|http://www.opensource.org/> but that allows distribution without restrictions. =back =head2 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 C<module>s (which can also mean a collection of modules), but some things are C<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. =head2 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 L<VERSION SPECIFICATIONS>. =head2 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 L<VERSION SPECIFICATIONS>. I<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 I<(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 L</requires>, L</build_requires>, and L</conflicts>, which have the same meaning in this subcontext as described elsewhere in this document.> =head2 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 L</"VERSION SPECIFICATIONS">. These dependencies are not required after the distribution is installed. =head2 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 L</"VERSION SPECIFICATIONS">. These dependencies are not required after the distribution is installed. =head2 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 C<conflicts> are the item names (module names or 'perl'), and the values are version specifications as described in L</"VERSION SPECIFICATIONS">. =head2 dynamic_config Example: dynamic_config: 0 (Spec 1.0) [optional] {boolean} A boolean flag indicating whether a F<Build.PL> or F<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). =head2 private I<(Deprecated)> (Spec 1.0) [optional] {map} This field has been renamed to L</no_index>. See below. =head2 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 L<Module::Build> that can generate the C<provides> mapping for your distribution automatically, make sure you examine what it generates to make sure it makes sense - indexers will usually trust the C<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 C<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. =head2 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 C<provides> field is present. For example, L<http://search.cpan.org/> excludes items listed in C<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. =head3 file (Spec 1.1) [optional] Exclude any listed file(s). =head3 directory (Spec 1.1) [optional] Exclude anything below the listed directory(ies). [Note: previous editions of the spec had C<dir> instead of C<directory>, but I think MakeMaker and various users started using C<directory>, so in deference we switched to that.] =head3 package (Spec 1.1) [optional] Exclude the listed package(s). =head3 namespace (Spec 1.1) [optional] Excludes anything below the listed namespace(s), but I<not> the listed namespace(s) its self. =head2 keywords Example: keywords: - make - build - install (Spec 1.1) [optional] {list} A sequence of keywords/phrases that describe this distribution. =head2 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 C<homepage>, C<license>, and C<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: =over 2 =item homepage The official home of this project on the web. =item license An URL for an official statement of this distribution's license. =item bugtracker An URL for a bug tracker (e.g. Bugzilla or RT queue) for this project. =back =head2 generated_by Example: generated_by: Module::Build version 0.20 (Spec 1.0) [required] {string} Indicates the tool that was used to create this F<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 F<META.yml> was generated by hand, it is suggested that the author be specified here. [Note: My F<meta_stats.pl> script which I use to gather statistics regarding F<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] =head1 VERSION SPECIFICATIONS Some fields require a version specification (ex. L</requires>, L</recommends>, L</build_requires>, etc.) to indicate the particular versionZ<>(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. C<2.4>. This means that B<at least> version 2.4 must be present. To indicate that B<any> version of a prerequisite is okay, even if the prerequisite doesn't define a version at all, use the version C<0>. You may also use the operators E<lt> (less than), E<lt>= (less than or equal), E<gt> (greater than), E<gt>= (greater than or equal), == (equal), and != (not equal). For example, the specification C<E<lt> 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 C<E<gt>= 1.2, != 1.5, E<lt> 2.0> indicates a version that must be B<at least> 1.2, B<less than> 2.0, and B<not equal to> 1.5. =head1 SEE ALSO L<CPAN|http://www.cpan.org/> L<CPAN.pm|CPAN> L<CPANPLUS> L<Data::Dumper> L<ExtUtils::MakeMaker> L<Module::Build> L<Module::Install> L<XML|http://www.w3.org/XML/> L<YAML|http://www.yaml.org/> =head1 HISTORY =over 4 =item March 14, 2003 (Pi day) =over 2 =item * Created version 1.0 of this document. =back =item May 8, 2003 =over 2 =item * Added the L</dynamic_config> field, which was missing from the initial version. =back =item November 13, 2003 =over 2 =item * Added more YAML rationale articles. =item * Fixed existing link to YAML discussion thread to point to new L<http://nntp.x.perl.org/group/> site. =item * Added and deprecated the L</private> field. =item * Added L</abstract>, C<configure>, C<requires_packages>, C<requires_os>, C<excludes_os>, and L</no_index> fields. =item * Bumped version. =back =item November 16, 2003 =over 2 =item * Added C<generation>, C<authored_by> fields. =item * Add alternative proposal to the L</recommends> field. =item * Add proposal for a C<requires_build_tools> field. =back =item December 9, 2003 =over 2 =item * Added link to latest version of this specification on CPAN. =item * Added section L</"VERSION SPECIFICATIONS">. =item * Chang name from Module::Build::META-spec to CPAN::META::Specification. =item * Add proposal for C<auto_regenerate> field. =back =item December 15, 2003 =over 2 =item * Add C<index> field as a compliment to L</no_index> =item * Add L</keywords> field as a means to aid searching distributions. =item * Add L</TERMINOLOGY> section to explain certain terms that may be ambiguous. =back =item July 26, 2005 =over 2 =item * 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. =item * Changed C<authored_by> to L</author>, since that's always been what it's actually called in actual F<META.yml> files. =item * Added the "==" operator to the list of supported version-checking operators. =item * Noted that the L</distribution_type> field is basically meaningless, and shouldn't really be used. =item * Clarified L</dynamic_config> a bit. =back =item August 23, 2005 =over 2 =item * Removed the name C<CPAN::META::Specification>, since that implies a module that doesn't actually exist. =back =item June 12, 2007 =over 2 =item * Added L</configure_requires>. =back =back