ExtUtils::ModuleMaker(3)

NAME
ExtUtils::ModuleMaker - Better than h2xs for creating modules

SYNOPSIS
At the command prompt:

    %   modulemaker

Inside a Perl program:

    use ExtUtils::ModuleMaker;

    $mod = ExtUtils::ModuleMaker->new(
        NAME => 'Sample::Module'
    );

    $mod->complete_build();

    $mod->dump_keys(qw|
        ...  # key provided as argument to constructor
        ...  # same
    |);

    $mod->dump_keys_except(qw|
        ...  # key provided as argument to constructor
        ...  # same
    |);

    $license = $mod->get_license();

    $mod->make_selections_defaults();

VERSION
This document references version 0.63 of ExtUtils::ModuleMaker, released to CPAN on July 31 2018.

DESCRIPTION
This module is a replacement for the most typical use of the h2xs utility bundled with all Perl distributions: the creation of the directories and files required for a pure-Perl module to be installable with make and distributable on the Comprehensive Perl Archive Network (CPAN).

h2xs has many options which are useful -- indeed, necessary -- for the creation of a properly structured distribution that includes C code as well as Perl code. Most of the time, however, h2xs is used as follows

    %   h2xs -AXn My::Module

to create a distribution containing only Perl code. ExtUtils::ModuleMaker is intended to be an easy-to-use replacement for this use of h2xs.

While you can call ExtUtils::ModuleMaker from within a Perl script (as in the SYNOPSIS above), it's easier to use with a command-prompt invocation of the modulemaker script bundled with this distribution:

    %   modulemaker

Then respond to the prompts. For Perl programmers, laziness is a virtue -- and modulemaker is far and away the laziest way to create a pure Perl distribution which meets all the requirements for worldwide distribution via CPAN.

USAGE

  Usage from the command-line with modulemaker
The easiest way to use ExtUtils::ModuleMaker is to invoke the modulemaker script from the command-line. You can control the content of the files built by modulemaker either by supplying command-line options or -- easier still -- replying to the screen prompts in modulemaker's interactive mode.

If you are encountering ExtUtils::ModuleMaker for the first time, you should turn now to the documentation for modulemaker which is bundled this distribution. Return to this document once you have become familiar with modulemaker.

  Use of Public Methods within a Perl Program
You can use ExtUtils::ModuleMaker within a Perl script to generate the directories and files needed to begin work on a CPAN-ready Perl distribution. You will need to call "new()" and "complete_build()", both of which are described in the next section. These two methods control the building of the file and directory structure for a new Perl distribution.

There are four other publicly available methods in this version of ExtUtils::ModuleMaker. "dump_keys", "dump_keys_except" and "get_license" are intended primarily as shortcuts for trouble-shooting problems with an ExtUtils::ModuleMaker object. "make_selections_defaults" enables you to be even lazier in your use of ExtUtils::ModuleMaker by saving keystrokes entered for attributes.

"new"

Creates and returns an ExtUtils::ModuleMaker object. Takes a list containing key-value pairs with information specifying the structure and content of the new module(s). (In this documentation, we will sometimes refer to these key-value pairs as the attributes of the ExtUtils::ModuleMaker object.) With the exception of key "EXTRA_MODULES" (see below), the values in these pairs are all strings. Like most such lists of key-value pairs, this list is probably best held in a hash. Keys which may be specified are:

•   Required Argument

    •   NAME

        The only required feature. This is the name of the primary module (with '"::"' separators if needed). Will no longer support the older, Perl 4-style separator ""'"" like the module D'Oh. There is no current default for NAME; you must supply a name explicitly.

•   Other Important Arguments

    •   ABSTRACT

        A short description of the module. CPAN likes to use this feature to describe the module. If the abstract contains an apostrophe ("'"), then the value corresponding to key "ABSTRACT" in the list passed to the constructor must be double-quoted; otherwise Makefile.PL gets messed up. Certain CPAN indexing features still work better if the abstract is 44 or fewer characters in length, but this does not appear to be as mandatory as in the past. (Defaults to dummy copy.)

    •   VERSION

        A string holding the version number. For alpha releases, include an underscore to the right of the dot like "0.31_21". (Default is 0.01.)

    •   LICENSE

        Which license to include in the Copyright section. You can choose one of the standard licenses by including 'perl', 'gpl', 'artistic', and 18 others approved by opensource.org. The default is to choose the 'perl' flavor which is to share it "under the same terms as Perl itself."

        Other licenses can be added by individual module authors to ExtUtils::ModuleMaker::Licenses::Local to keep your company lawyers happy.

        Some licenses include placeholders that will be replaced with AUTHOR information.

    •   BUILD_SYSTEM

        This can take one of three values:

        •   'ExtUtils::MakeMaker'

            The first generates a basic Makefile.PL file for your module.

        •   'Module::Build'

            The second creates a Build.PL file.

        •   'Module::Build and Proxy'

            The third creates a Build.PL along with a proxy Makefile.PL script that attempts to install Module::Build if necessary, and then runs the Build.PL script. This option is recommended if you want to use Module::Build as your build system. See Module::Build::Compat for more details.

            Note: To correct a discrepancy between the documentation and code in earlier versions of ExtUtils::ModuleMaker, we now explicitly provide this synonym for the third option:

                'Module::Build and proxy Makefile.PL'

            (Thanks to David A Golden for spotting this bug.)

    •   COMPACT

        For a module named "Foo::Bar::Baz" creates a base directory named "Foo-Bar-Baz" instead of Foo/Bar/Baz. (Default is off.)

    •   VERBOSE

        Prints messages to STDOUT as it creates directories, writes files, etc. (Default is off.)

    •   PERMISSIONS

        Used to create new directories. (Default is 0755: group and world can not write.)

    •   USAGE_MESSAGE

        Message given when the module "die"s. Scripts should set this to the same string it would print if the user asked for help. (A reasonable default is provided.)

    •   NEED_POD

        Include POD section in *.pm files created. (Default is on.)

    •   NEED_NEW_METHOD

        Include a simple "new()" method in the *.pm files created. (Default is on.)

    •   CHANGES_IN_POD

        Omit a Changes file, but instead add a HISTORY section to the POD. (Default is off).

    •   INCLUDE_MANIFEST_SKIP

        Boolean value which, if true, includes a MANIFEST.SKIP file in the distribution with reasonable default values facilitating use of the make manifest command during module development. (Thanks to David A Golden for this feature. Default is off.)

    •   INCLUDE_TODO

        Boolean value which, if true, includes a Todo file in the distribution in which the module's author or maintainer can discuss future lines of development. (Default is on.)

    •   INCLUDE_LICENSE

        Boolean value which, if true, includes a LICENSE file in the distribution. (Which LICENSE file is determined in the LICENSE option.) (Default is on.)

    •   INCLUDE_SCRIPTS_DIRECTORY

        Boolean value which, if true, includes a scripts/ directory (at the same level as lib/ or t/). (Default is on.)

    •   INCLUDE_WARNINGS

        Boolean value which, if true, inserts "use warnings;" in all Perl modules created by use of this module. (Default is off.)

    •   INCLUDE_ID_LINE

        Boolean value which, if true, inserts "#$Id$" in all Perl modules created by use of this module for the purpose of inserting a Subversion file 'Id' string. (Default is off.)

•   Arguments Related to the Module's Author

    •   AUTHOR

        Name of the author. If the author's name contains an apostrophe ("'"), then the corresponding value in the list passed to the constructor must be double-quoted; otherwise Makefile.PL gets messed up. (Defaults to dummy copy.)

    •   EMAIL

        Email address of the author. If the author's e-mail address contains an apostrophe ("'"), then the corresponding value in the list passed to the constructor must be double-quoted; otherwise Makefile.PL gets messed up. (Defaults to dummy copy.)

    •   CPANID

        The CPANID of the author. (Defaults to dummy copy. To suppress printing of this line entirely, set "CPANID" to a Perl-false value such as an empty string.)

    •   WEBSITE

        The personal or organizational website of the author. (Defaults to dummy copy. To suppress printing of this line entirely, set "CPANID" to a Perl-false value such as an empty string.)

    •   ORGANIZATION

        Company or group owning the module. (Defaults to dummy copy. To suppress printing of this line entirely, set "CPANID" to a Perl-false value such as an empty string.)

•   Argument Related to Multiple Modules within a Distribution

    •   EXTRA_MODULES

        A reference to an array of hashes, each of which contains values for additional modules in the distribution.

            $mod = ExtUtils::ModuleMaker->new(
                NAME           => 'Alpha::Beta',
                EXTRA_MODULES  => [
                    { NAME => 'Alpha::Beta::Gamma' },
                    { NAME => 'Alpha::Beta::Delta' },
                    { NAME => 'Alpha::Beta::Gamma::Epsilon' },
                ],
            );

        As with the primary module, the only attribute required for each extra module is "NAME". Other attributes may be supplied but the primary module's values will be used if no value is given here.

        Each extra module will be created in the correct relative place in the lib directory. By default, a test file will also be created in the t directory corresponding to each extra module to test that it loads properly. (See EXTRA_MODULES_SINGLE_TEST_FILE below to learn how to change this behavior.) However, no other supporting documents (e.g., README, Changes) will be created.

        This is one major improvement over the earlier h2xs as you can now build multi-module packages.

•   Arguments Related to Test Files

    •   FIRST_TEST_NUMBER

        A non-negative natural number from which the count begins in test files that are numerically ordered. (Default is 1.)

    •   TEST_NUMBER_FORMAT

        In test files that are numerically ordered, a Perl "sprintf" formatting string that specifies how FIRST_TEST_NUMBER is to be formatted. (Default is "%03d".)

    •   TEST_NAME

        String forming the core of the name of a test file. (Default is "load").

    •   TEST_NAME_DERIVED_FROM_MODULE_NAME

        Boolean value which, when true, tells ExtUtils::ModuleMaker to create a file in the test suite with a name derived from the .pm package it is testing, thereby overriding any value set in the TEST_NAME attribute. For example, for a module called 'Alpha::Sigma::Tau', a test file named t/Alpha_Sigma_Tau.t will be created. (Default is off.)

    •   TEST_NAME_SEPARATOR

        String holding the character which joins components of a test file's name, e.g., the character used to join 001 and <load> in a file named 001_load.t. (Defaults to an underscore "_".)

    •   EXTRA_MODULES_SINGLE_TEST_FILE

        Boolean value which, when true and when extra modules have been specified in the EXTRA_MODULES attribute, will put tests for those extra modules in a single test file rather than in individual test files corresponding to each module. (Default is off.)

    •   INCLUDE_POD_COVERAGE_TEST

        Boolean value which, if true, causes a test file called t/pod-coverage.t to be included in the t/ directory. This test is advocated by some Perl quality assurance experts and module authors. However, since the maintainer of ExtUtils::ModuleMaker is not persuaded of its worth, default is off.

    •   INCLUDE_POD_TEST

        Boolean value which, if true, causes a test file called t/pod.t to be included in the t/ directory. This test is advocated by some Perl quality assurance experts and module authors. However, since the maintainer of ExtUtils::ModuleMaker is not persuaded of its worth, default is off.

    •   INCLUDE_FILE_IN_PM

        String holding a path to a file containing Perl code and/or documentation which will be included in each lib/*.pm file created in a particular distribution. By default, such content is placed after any constructor and before the main POD block. This could, for example, be used to insert stub subroutines in each package within a distribution. Default is off.

•   Arguments for Advanced Usages

    •   INTERACTIVE

        Activates interactive mode in modulemaker utility. The interactive mode presents the user with a series of menus from which the user selects features by entering text at the command prompt. This attribute should only be used by interactive scripts like modulemaker. (Default is off.)

    •   ALT_BUILD

        Name of a Perl package holding methods which override those called withiin "complete_build" to shape the content of files created by using ExtUtils::ModuleMaker. See "An Alternative Approach to Subclassing" below.

"complete_build"

Creates all directories and files as configured by the key-value pairs passed to "ExtUtils::ModuleMaker::new". Returns a true value if all specified files are created -- but this says nothing about whether those files have been created with the correct content.

"dump_keys"

When troubleshooting problems with an ExtUtils::ModuleMaker object, it is often useful to use Data::Dumper to dump the contents of the object. Use "dump_keys()" when you only need to examine a few of the object's attributes.

    $mod->dump_keys( qw| NAME ABSTRACT | );

"dump_keys_except"

When troubleshooting problems with an ExtUtils::ModuleMaker object, it is often useful to use Data::Dumper to dump the contents of the object. However, since certain elements of that object are often quite lengthy (e.g, the values of keys "LicenseParts" and "USAGE_MESSAGE"), it's handy to have a dumper function that dumps all keys except certain designated keys.

    $mod->dump_keys_except(qw| LicenseParts USAGE_MESSAGE |);

"get_license"

Returns a string which nicely formats a short version of the License and Copyright information.

    $license = $mod->get_license();
    print $license;

... will print something like this:

    =====================================================================
    =====================================================================
    [License Information]
    =====================================================================
    =====================================================================
    [Copyright Information]
    =====================================================================
    =====================================================================

(Earlier versions of ExtUtils::ModuleMaker contained a "Display_License" function in each of submodules ExtUtils::ModuleMaker::Licenses::Standard and ExtUtils::ModuleMaker::Licenses::Local. These functions were never publicly documented or tested. "get_license()" is intended as a replacement for those two functions.)

"make_selections_defaults()"

Saves the values you entered as arguments passed to "new()" in a personal defaults file so that they supersede the defaults provided by ExtUtils::ModuleMaker itself.

This is an advanced usage of ExtUtils::ModuleMaker. If you have used ExtUtils::ModuleMaker more than once, you have probably typed in a choice for "AUTHOR", "EMAIL", etc., more than once. To save unnecessary typing and reduce typing errors, ExtUtils::ModuleMaker now offers you the possibility of establishing personal default values which override the default values supplied with the distribution and found in lib/ExtUtils/ModuleMaker/Defaults.pm.

Suppose that you have called "ExtUtils::ModuleMaker::new()" as follows:

    $mod = ExtUtils::ModuleMaker->new(
        NAME            => 'Sample::Module',
        ABSTRACT        => 'Now is the time to join the party',
        AUTHOR          => 'Hilton Stallone',
        CPANID          => 'RAMBO',
        ORGANIZATION    => 'Parliamentary Pictures',
        WEBSITE         => 'http://parliamentarypictures.com',
        EMAIL           => 'hiltons@parliamentarypictures.com',
    );

While $mod is still in scope, you can call:

    $mod->make_selections_defaults()

and the values selected -- with two important exceptions -- will be saved in a Personal/Defaults.pm file stored in your home directory. The next time you invoke ExtUtils::ModuleMaker, the new values will appear in the appropriate locations in the files created by "complete_build()". They will also appear in the menus provided on screen by the modulemaker utility.

What are those two important exceptions?

•   "NAME"

    You cannot enter a default value for "NAME": the name of the module you are creating. ExtUtil::ModuleMaker's own defaults file omits a value for "NAME" to prevent you from overwriting an already existing module. (More precisely, the default value is an empty string. ExtUtil::ModuleMaker will throw an error if you attempt to create a module whose name is empty.) This precaution applies to your personal defaults file as well.

•   "ABSTRACT"

    Since every module you create presumably has its own unique purpose, every module must have a unique "ABSTRACT" to summarize that purpose. ExtUtil::ModuleMaker supplies the following string as the default value for the "ABSTRACT" key:

        Module abstract (<= 44 characters) goes here

    ... a string which, not coincidentally, happens to be exactly 44 characters long -- so you can just overstrike it. This will be the default value for "ABSTRACT" in any Personal/Defaults.pm file you create as well.

CUSTOMIZATION
ExtUtils::ModuleMaker is designed to be customizable to your needs and to offer you more flexibility as you become more experienced with it.

  Via modulemaker Utility Interactive Mode
As with everything else about ExtUtils::ModuleMaker, the easiest, laziest way to get started is via the modulemaker utility; see its documentation. Suppose that you have entered your correct name, email address and website at the prompts in modulemaker's Author Menu.

  ------------------------

  modulemaker: Author Menu

      Feature       Current Value
  N - Author        'John Q Public'
  C - CPAN ID       'MODAUTHOR'
  O - Organization  'XYZ Corp.'
  W - Website       'http://public.net/~jqpublic'
  E - Email         'jqpublic@public.net'

  R - Return to main menu
  X - Exit immediately

  Please choose which feature you would like to edit:

Why should you ever have to enter this information again? Return to the modulemaker Main Menu ("R").

  ------------------------

  modulemaker: Main Menu

      Feature                     Current Value
  N - Name of module              ''
  S - Abstract                    'Module abstract (<= 44 characters) goes here'
  A - Author information
  L - License                     'perl'
  D - Directives
  B - Build system                'ExtUtils::MakeMaker'

  G - Generate module
  H - Generate module;
      save selections as defaults

  X - Exit immediately

  Please choose which feature you would like to edit:

Select "H" instead of "G" to generate the distribution. An internal call to "make_selections_defaults()" will save those selections in a personal defaults file and present them to you on the Author Menu the next time you go to use it.

  Via modulemaker Utility Command-Line Options Mode
For simplicity, not all of ExtUtils::ModuleMaker's default values are represented on modulemaker's menus. Those that are not represented on those menus cannot be changed from there. They can, however, in many cases be specified as options passed to modulemaker on the command-line and automatically saved as personal defaults by including the "s" flag as one of those options. If, for example, your name is 'John Q Public' and you want all modules you create to have compact top-level directories, you would call:

    %   modulemaker -Icsn Sample::Module -u 'John Q Public'

A distribution with a top-level directory Sample-Module would be created. 'John Q Public' would appear in appropriate places in Sample-Module/Makefile.PL and Sample-Module/lib/Sample/Module.pm. You could then throw away the entire Sample-Module directory tree. The next time you call "modulemaker", the call

    %   modulemaker -In Second::Module

would suffice to generate a compact top-level directory and 'John Q Public' would appear in appropriate locations instead of the dreaded 'A. U. Thor'.

  Via "ExtUtils::ModuleMaker::new()"
In all cases, ExtUtils::ModuleMaker's default values can be overridden with arguments passed to "new()" inside a Perl program. The overriding can then be made permanent by calling "make_selections_defaults()".

Suppose, for example,

1.  that you want the files in your test suite to appear in a numerical order starting from 0 rather than ExtUtils::ModuleMaker's own default starting point of 1;

2.  that you want the number in the test file's name to be formatted as a two-digit string padded with zeroes rather than ExtUtils::ModuleMaker's own default format of a three-digit, zero-padded string;

3.  that you want the numerical part of the test filename to be joined to the lexical part with a dot (".") rather than ExtUtils::ModuleMaker's own default linkage character of an underscore ("_"); and

4.  that you want the lexical part of the test filename to reflect the module's name rather than ExtUtils::ModuleMaker's default of "load".

Your Perl program would look like this:

    #!/usr/local/bin/perl
    use strict;
    use warnings;
    use ExtUtils::ModuleMaker;

    my $mod = ExtUtils::ModuleMaker->new(
        NAME        => 'Sample::Module',
        AUTHOR      => 'John Q Public',
        COMPACT     => 1,
        FIRST_TEST_NUMBER    => 0,
        TEST_NUMBER_FORMAT   => "%02d",
        TEST_NAME_SEPARATOR  => q{.},
        TEST_NAME_DERIVED_FROM_MODULE_NAME => 1,
    );

    $mod->make_selections_defaults();

A subsequent call to the modulemaker utility,

    %    modulemaker -In Second::Balcony::Jump

would generate a directory tree with a compact top-level, 'John Q Public' in appropriate locations in Second-Balcony-Jump/Makefile.PL and Second-Balcony-Jump/lib/Second/Balcony/Jump.pm and a test file called Second-Balcony-Jump/t/00.Second.Balcony.Jump.t.

  Via Subclassing ExtUtils::ModuleMaker
If you're a power-user, once you start playing with ExtUtils::ModuleMaker, you won't be able to stop. You'll ask yourself, "Self, if I can change the default values, why can't I change the 'boilerplate' copy that appears inside the files which ExtUtils::ModuleMaker creates?"

Now, you can. You can hack on the methods which "ExtUtils::ModuleMaker::new()" and "complete_build()" call internally to customize their results to your heart's desire. The key: build an entirely new Perl extension whose lib/*.pm file has methods that override the methods you need overridden -- and only those methods. Follow these steps:

1. Study ExtUtils::ModuleMaker::Defaults, ::Initializers and ::StandardText

ExtUtils::ModuleMaker's default values are stored in lib/ExtUtils/ModuleMaker/Defaults.pm, specifically, in its "default_values()" method. Identify those values which you wish to change.

ExtUtils::ModuleMaker's other internal methods are found in two other files: /lib/ExtUtils/ModuleMaker/Initializers.pm and lib/ExtUtils/ModuleMaker/StandardText.pm. Rule of thumb: If an internal method is called within "new()", it is found in ExtUtils::ModuleMaker::Initializers. If it is called within "complete_build()", it is found in ExtUtils::ModuleMaker::StandardText. Study these two packages to identify the methods you wish to override.

Hint: If changing a default value in ExtUtils::ModuleMaker::Defaults will achieve your objective, make that change rather than trying to override methods in ExtUtils::ModuleMaker::Initializers or ExtUtils::ModuleMaker::StandardText.

Hint: You should probably think about overriding methods in ExtUtils::ModuleMaker::StandardText before overriding those in ExtUtils::ModuleMaker::Initializers.

2. Use modulemaker to Create the Framework for a New Distribution

You're creating a new Perl extension. Who ya gonna call? modulemaker, natch! (If you have not read the documentation for modulemaker by this point, do so now.)

Suppose that you've gotten on the 'Perl Best Practices' bandwagon and want to create all your Perl extensions in the style recommended by Damian Conway in the book of the same name. Use modulemaker to create the framework:

    %    modulemaker -Icqn ExtUtils::ModuleMaker::PBP \
         -u 'James E Keenan' \
         -p JKEENAN \
         -o 'Perl Seminar NY' \
         -w http://search.cpan.org/~jkeenan/

You used the "-q" option above because you do not want or need a constructor in the new package you are creating. That package will inherit its constructor from ExtUtils::ModuleMaker.

3. Edit the lib/*.pm File

Open up the best text-editor at your disposal and proceed to hack:

    %    vi ExtUtils-ModuleMaker-PBP/lib/ExtUtils/ModuleMaker/PBP.pm

Add this line near the top of the file:

    use base qw{ ExtUtils::ModuleMaker };

so that ExtUtils::ModuleMaker::PBP inherits from ExtUtils::ModuleMaker (which, in turn, inherits from ExtUtils::ModuleMaker::Defaults, ExtUtils::ModuleMaker::Initializers and ExtUtils::ModuleMaker::StandardText).

If you have carefully studied ExtUtils::ModuleMaker::Defaults, ExtUtils::ModuleMaker::StandardText and Perl Best Practices, you will write methods including the following:

    sub default_values {
        my $self = shift;
        my $defaults_ref = $self->SUPER::default_values();
        $defaults_ref->{COMPACT}                        = 1;
        $defaults_ref->{FIRST_TEST_NUMBER}              = 0;
        $defaults_ref->{TEST_NUMBER_FORMAT}             = "%02d";
        $defaults_ref->{EXTRA_MODULES_SINGLE_TEST_FILE} = 1;
        $defaults_ref->{TEST_NAME_SEPARATOR}            = q{.};
        $defaults_ref->{INCLUDE_TODO}                   = 0;
        $defaults_ref->{INCLUDE_POD_COVERAGE_TEST}      = 1;
        $defaults_ref->{INCLUDE_POD_TEST}               = 1;
        return $defaults_ref;;
    }

    sub text_Makefile {
        my $self = shift;
        my $Makefile_format = q~
    use strict;
    use warnings;
    use ExtUtils::MakeMaker;

    WriteMakefile(
        NAME            => '%s',
        AUTHOR          => '%s <%s>',
        VERSION_FROM    => '%s',
        ABSTRACT_FROM   => '%s',
        PL_FILES        => {},
        PREREQ_PM    => {
            'Test::More'    => 0,
            'version'       => 0,
        },
        dist            => { COMPRESS => 'gzip -9f', SUFFIX => 'gz', },
        clean           => { FILES => '%s-*' },
    );
    ~;
        my $text_of_Makefile = sprintf $Makefile_format,
            map { my $s = $_; $s =~ s{'}{\\'}g; $s; }
                $self->{NAME},
                $self->{AUTHOR},
                $self->{EMAIL},
                $self->{FILE},
                $self->{FILE},
                $self->{FILE};
        return $text_of_Makefile;
    }

Of course, for true Perl laziness, you'll use CPAN distribution ExtUtils::ModuleMaker::PBP, written by the author of ExtUtils::ModuleMaker as an exemplar of subclassing ExtUtils::ModuleMaker and generating the same output as Damian Conway's Module::Starter::PBP.

4. Test

How do you know you have correctly subclassed ExtUtils::ModuleMaker? With a test suite, of course. With careful editing, you can use many of ExtUtils::ModuleMaker's own tests in your new distribution. You will, of course, have to change a number of tests, because the default values implied by Conway's recommendations are different from ExtUtils::ModuleMaker's own defaults. Among other things, you will have to do a search-and-replace on all constructor calls.

    %    perl -pi'*.bak' -e 's{ExtUtils::ModuleMaker->new}{ExtUtils::ModuleMaker::PBP->new}g;'

Of course, you should have written your tests first, right?

5. Install and Use

You would install your new distribution as you would any other Perl distribution, i.e., with either ExtUtils::MakeMaker or Module::Build, depending on which you chose in creating your subclass.

    #!/usr/local/bin/perl
    use strict;
    use warnings;
    use ExtUtils::ModuleMaker::PBP;

    my $mod = ExtUtils::ModuleMaker::PBP->new(
        NAME        => 'Sample::Module',
    );

    $mod->complete_build();

For an adaptation of the modulemaker utility to work with ExtUtils::ModuleMaker::PBP, see mmkrpbp which is bundled with the latter package.

An Alternative Approach to Subclassing

There is one other way to subclass to ExtUtils::ModuleMaker which bears mentioning, more because the author used it in the development of this version of ExtUtils::ModuleMaker than because it is recommended. If for some reason you do not wish to create a full-fledged Perl distribution for your subclass, you can simply write the subclassing package and store it in the same directory hierarchy on your system in which your personal defaults file is stored.

For example, suppose you are experimenting and only wish to override one method in ExtUtils::ModuleMaker::StandardText. You can create a package called ExtUtils::ModuleMaker::AlternativeText. If you are working on a Unix-like system, you would move that file such that its path would be:

    "$ENV{HOME}/.modulemaker/ExtUtils/ModuleMaker/AlternativeText.pm"

You would then add one argument to your call to "ExtUtils::ModuleMaker::new()":

    my $mod = ExtUtils::ModuleMaker->new(
        NAME        => 'Sample::Module',
        ALT_BUILD   => 'ExtUtils::ModuleMaker::AlternativeText',
    );

CAVEATS

•   Require Perl 5.6.1

    Support for versions of Perl earlier than 5.6.1 was dropped in version 0.57 released in May 2018.

•   Testing of modulemaker's Interactive Mode

    The easiest, laziest and recommended way of using this distribution is the command-line utility modulemaker, especially its interactive mode. However, this is necessarily the most difficult test, as its testing would require capturing the STDIN, STDOUT and STDERR for a process spawned by a "system('modulemaker')" call from within a test file. For now, the maintainer has relied on repeated visual inspection of the screen prompts generated by modulemaker. With luck, Expect-based tests will be available in a future version.

•   Testing modulemaker on Non-*nix-Like Operating Systems

    Since testing the modulemaker utility from within the test suite requires a "system()" call, a clean test run depends in part on the way a given operating system parses command-line arguments. The maintainer has tested this on Darwin and Win32 and, thanks to a suggestion by A. Sinan Unur, solved a problem on Win32. Results on other operating systems may differ; feedback is welcome.

TO DO

•   Tests for modulemaker's interactive mode.

•   Possible new "USE_AS_BASE" attribute which would insert modules from which user's new module will inherit.

        USE_AS_BASE => [ qw|
            Template::Toolkit
            Module::Build
            Lingua::Romana::Perligata
            Acme::Buffy
        | ],

    Such an attribute would require replacement copy for "ExtUtils::ModuleMaker::StandardText::block_begin()".

AUTHOR/MAINTAINER
ExtUtils::ModuleMaker was originally written in 2001-02 by R. Geoffrey Avery (modulemaker [at] PlatypiVentures [dot] com). Since version 0.33 (July 2005) it has been maintained by James E. Keenan (jkeenan [at] cpan [dot] org).

SUPPORT
Send email to jkeenan [at] cpan [dot] org. Please include 'modulemaker' in the subject line. Please report any bugs or feature requests to "bug-ExtUtils-ModuleMaker@rt.cpan.org", or through the web interface at <http://rt.cpan.org>.

Development repository: <https://github.com/jkeenan/extutils-modulemaker>

ACKNOWLEDGMENTS
Thanks first and foremost to Geoff Avery for creating ExtUtils::ModuleMaker and popularizing it via presentations I attended at YAPC::NA::2003 (Boca Raton) and YAPC::EU::2003 (Paris).

Soon after I took over maintenance of ExtUtils::ModuleMaker, David A Golden became a driving force in its ongoing development, providing suggestions for additional functionality as well as bug reports. David is the author of ExtUtils::ModuleMaker::TT which, while not a pure subclass of ExtUtils::ModuleMaker, extends its functionality for users of Template::Toolkit.

Thanks for suggestions about testing the modulemaker utility to Michael G Schwern on perl.qa and A Sinan Unur and Paul Lalli on comp.lang.perl.misc. Thanks for help in dealing with a nasty bug in the testing to Perlmonks davidrw and tlm. That well known Perl hacker, Anonymous Guest, contributed another bug report on rt.cpan.org.

As development proceeded, several issues were clarified by members of Perlmonks.org. CountZero, xdg, Tanktalus, holli, TheDamian and nothingmuch made particularly useful suggestions, as did Brian Clarkson.

Thanks also go to the following beta testers: Alex Gill, Marc Prewitt, Scott Godin, Reinhard Urban and imacat.

Version 0.39 of ExtUtils::ModuleMaker encountered spurious testing failure reports from testers.cpan.org. These were eventually diagnosed as being due to bugs in the automated testing programs and/or their operating environments on different systems -- i.e., to problems outside ExtUtils::ModuleMaker itself. Several Perlmonks helped investigate this problem: chromatic, dave_the_m, randyk, and njh.

Thanks to Paul M Sirianni for reporting bugs that led to versions 0.48 and 0.51.

Thanks to Chris Kirke for pointing to reports at http://cpants.cpanauthors.org/dist/ExtUtils-ModuleMaker of inconsistent $VERSION numbers across the component files.

COPYRIGHT
Copyright (c) 2001-2002 R. Geoffrey Avery. Revisions from v0.33 forward (c) 2005-2015 James E. Keenan. All rights reserved. This program is free software; you can redistribute it and/or modify it under the same terms as Perl itself.

The full text of the license can be found in the LICENSE file included with this module.

DISCLAIMER OF WARRANTY
BECAUSE THIS SOFTWARE IS LICENSED FREE OF CHARGE, THERE IS NO WARRANTY FOR THE SOFTWARE, TO THE EXTENT PERMITTED BY APPLICABLE LAW. EXCEPT WHEN OTHERWISE STATED IN WRITING THE COPYRIGHT HOLDERS AND/OR OTHER PARTIES PROVIDE THE SOFTWARE "AS IS" WITHOUT WARRANTY OF ANY KIND, EITHER EXPRESSED OR IMPLIED, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. THE ENTIRE RISK AS TO THE QUALITY AND PERFORMANCE OF THE SOFTWARE IS WITH YOU. SHOULD THE SOFTWARE PROVE DEFECTIVE, YOU ASSUME THE COST OF ALL NECESSARY SERVICING, REPAIR, OR CORRECTION.

IN NO EVENT UNLESS REQUIRED BY APPLICABLE LAW OR AGREED TO IN WRITING WILL ANY COPYRIGHT HOLDER, OR ANY OTHER PARTY WHO MAY MODIFY AND/OR REDISTRIBUTE THE SOFTWARE AS PERMITTED BY THE ABOVE LICENCE, BE LIABLE TO YOU FOR DAMAGES, INCLUDING ANY GENERAL, SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMAGES ARISING OUT OF THE USE OR INABILITY TO USE THE SOFTWARE (INCLUDING BUT NOT LIMITED TO LOSS OF DATA OR DATA BEING RENDERED INACCURATE OR LOSSES SUSTAINED BY YOU OR THIRD PARTIES OR A FAILURE OF THE SOFTWARE TO OPERATE WITH ANY OTHER SOFTWARE), EVEN IF SUCH HOLDER OR OTHER PARTY HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH DAMAGES.

SEE ALSO
modulemaker, perlnewmod, h2xs, ExtUtils::MakeMaker, Module::Build, ExtUtils::ModuleMaker::PBP, ExtUtils::ModuleMaker::TT, mmkrpbp.