Provided by: libcpan-meta-perl_2.150010-2_all 
NAME
CPAN::Meta::History::Meta_1_1 - Version 1.1 metadata specification for META.yml
PREFACE
This is a historical copy of the version 1.1 specification for META.yml files, copyright
by Ken Williams and licensed under the same terms as Perl itself.
Modifications from the original:
• Conversion from the original HTML to POD format
• Include list of valid licenses from Module::Build 0.18 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.
DESCRIPTION
This document describes version 1.1 of the META.yml specification.
The META.yml file describes important properties of contributed Perl distributions such as
the ones found on CPAN <http://www.cpan.org>. It is typically created by tools like
Module::Build and ExtUtils::MakeMaker.
The fields in the META.yml file are meant to be helpful to people maintaining module
collections (like CPAN), for people writing installation tools (like CPAN or CPANPLUS), or
just people who want to know some stuff about a distribution before downloading it and
starting to install it.
Format
META.yml files are written in the YAML <http://www.yaml.org/> format. The reasons we
chose YAML instead of, say, XML or Data::Dumper are discussed in this thread
<http://www.nntp.perl.org/group/perl.makemaker/2002/04/msg406.html> on the MakeMaker
mailing list.
The first line of a META.yml file should be a valid YAML document header
<http://yaml.org/spec/history/2002-10-31.html#syntax-document> like "--- #YAML:1.0"
Fields
The rest of the META.yml file is one big YAML mapping
<http://yaml.org/spec/history/2002-10-31.html#syntax-mapping>, whose keys are described
here.
name
Example: "Module-Build"
The name of the distribution. 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 <http://search.cpan.org/author/GAAS/libwww-perl/>
distribution.
version
Example: 0.16
The version of the distribution to which the META.yml file refers. This is a
mandatory field.
The version is essentially an arbitrary string, but must be only ASCII characters, and
strongly should be of the format integer-dot-digit-digit, i.e. 25.57, optionally
followed by underscore-digit-digit, i.e. "25.57_04".
The standard tools that deal with module distribution (PAUSE, CPAN, etc.) form an
identifier for each distribution by joining the 'name' and 'version' attributes with a
dash ("-") character. Tools who are prepared to deal with distributions that have no
version numbers generally omit the dash as well.
license
Example: "perl"
a descriptive term for the licenses ... not authoritative, but must be consistent with
licensure statements in the READMEs, documentation, etc.
The license under which this distribution may be used and redistributed.
Must be one of the following 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
version 1 or the Artistic version 1 license.
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>).
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>).
open_source
The distribution is licensed under some other Open Source Initiative-approved
license listed at <http://www.opensource.org/licenses/>.
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.
restrictive
The distribution may not be redistributed without special permission from the
author and/or copyright holder.
license_uri
This should contain a URI where the exact terms of the license may be found.
(change "unrestricted" to "redistributable"?)
distribution_type
Example: "module"
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.
This field is basically meaningless, and tools (like Module::Build or MakeMaker) will
likely stop generating it in the future.
private
WTF is going on here?
index_ignore: any application that indexes the contents of distributions (PAUSE,
search.cpan.org) ought to ignore the items (packages, files, directories, namespace
hierarchies).
requires
Example:
Data::Dumper: 0
File::Find: 1.03
A YAML mapping <http://yaml.org/spec/history/2002-10-31.html#syntax-mapping>
indicating the Perl modules this distribution requires for proper operation. The keys
are the module names, and the values are version specifications as described in the
documentation for Module::Build's "requires" parameter.
Note: the exact nature of the fancy specifications like ">= 1.2, != 1.5, < 2.0" is
subject to change. Advance notice will be given here. The simple specifications like
"1.2" will not change in format.
recommends
Example:
Data::Dumper: 0
File::Find: 1.03
A YAML mapping <http://yaml.org/spec/history/2002-10-31.html#syntax-mapping>
indicating the Perl modules this distribution recommends for enhanced operation.
build_requires
Example:
Data::Dumper: 0
File::Find: 1.03
A YAML mapping <http://yaml.org/spec/history/2002-10-31.html#syntax-mapping>
indicating the Perl modules required for building and/or testing of this distribution.
These dependencies are not required after the module is installed.
conflicts
Example:
Data::Dumper: 0
File::Find: 1.03
A YAML mapping <http://yaml.org/spec/history/2002-10-31.html#syntax-mapping>
indicating the Perl modules that cannot be installed while this distribution is
installed. This is a pretty uncommon situation.
- possibly separate out test-time prereqs, complications include: can tests be
meaningfully preserved for later running? are test-time prereqs in addition to build-
time, or exclusive?
- make official location for installed *distributions*, which can contain tests, etc.
dynamic_config
Example: 0
A boolean flag indicating whether a Build.PL or Makefile.PL (or similar) must be
executed, or whether this module can be built, tested and installed solely from
consulting its metadata file. The main reason to set this to a true value if 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.pm to do something useful with it. It
can potentially bring lots of security, packaging, and convenience improvements.
generated_by
Example: "Module::Build version 0.16"
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.
Ingy's suggestions
short_description
add as field, containing abstract, maximum 80 characters, suggested minimum 40
characters
description
long version of abstract, should add?
maturity
alpha, beta, gamma, mature, stable
author_id, owner_id
categorization, keyword, chapter_id
URL for further information
could default to search.cpan.org on PAUSE
namespaces
can be specified for single elements by prepending dotted-form, i.e.
"com.example.my_application.my_property". Default namespace for META.yml is probably
"org.cpan.meta_author" or something. Precedent for this is Apple's Carbon namespaces,
I think.
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.