Add documentation on Perl packages.

[ssurbhi560]

Closes #1536

PR Checklist:

• make all edits to the docs in the src directory, not in docs or in the html files
• note any issues closed by this PR with closing keywords
• put any other relevant information below

[kathatherine]

This will be a good help to maintainers. Thanks for writing this up! I just have a few edits and questions.

[ssurbhi560]

Thanks for taking the time to review the PR @jmarshall and @nsoranzo! :)
I will update it as you suggested.

[jmarshall]

This is good as far as it goes, and IMHO would usefully be merged as such.

Currently in bioconda there are 315 Perl packages using ExtUtils::MakeMaker and 119 using Module::Build. If the statistics for conda-forge are similar, it would be useful to add the corresponding advice for configuring Module::Build as well.

[kathatherine]

A couple things. Great work!

[kathatherine]

Thanks for adding that! I added a few rewrites.

[kathatherine]

Suggested change

	The other build system used for Perl packages is ``Module::Build``. ``Module::Build`` is a system for building, testing, and installing Perl modules.
	It is an alternative to ``ExtUtils::MakeMaker``. It does not require ``make`` - most of the ``Module::Build`` code is pure Perl and written in a very cross-platform way.
	The recipe of some of the Perl packages that uses ``Module::Build`` are :
	- `perl-math-derivative <https://github.com/bioconda/bioconda-recipes/blob/master/recipes/perl-math-derivative/meta.yaml>`__
	- `perl-graphics-colornames <https://github.com/bioconda/bioconda-recipes/blob/master/recipes/perl-graphics-colornames/meta.yaml>`__
	- `mirnature <https://github.com/bioconda/bioconda-recipes/blob/master/recipes/mirnature/meta.yaml>`__
	To know more about ``Module::Build`` and difference between the two build systems read `Comparison <https://metacpan.org/pod/Module::Build#COMPARISON>`__ and `Module::Build <https://metacpan.org/pod/Module::Build>`__.
	The other build system used for Perl packages is ``Module::Build``, which is a system for building, testing, and installing Perl modules.
	It is an alternative to ``ExtUtils::MakeMaker``. It does not require ``make``; most of the ``Module::Build`` code is pure Perl and written in a very cross-platform way.
	The recipes of some of the Perl packages that use ``Module::Build`` are:
	- `perl-math-derivative <https://github.com/bioconda/bioconda-recipes/blob/master/recipes/perl-math-derivative/meta.yaml>`__
	- `perl-graphics-colornames <https://github.com/bioconda/bioconda-recipes/blob/master/recipes/perl-graphics-colornames/meta.yaml>`__
	- `mirnature <https://github.com/bioconda/bioconda-recipes/blob/master/recipes/mirnature/meta.yaml>`__
	To know more about ``Module::Build`` and differences between the two build systems, see the `Module::Build <https://metacpan.org/pod/Module::Build>`__ page, paying special attention to the `Comparison <https://metacpan.org/pod/Module::Build#COMPARISON>`__ section.

[jmarshall]

With respect, the information that has been added about Module::Build is entirely not what this document's audience needs to know. The reader is packaging an existing Perl module that has already chosen between the two systems, so they already know what they are and don't need to know the pros and cons of each.

What this audience does need from this document is to be told the Module::Build equivalent of the recommended perl Makefile.PL INSTALLDIRS=vendor NO_PERLLOCAL=1 NO_PACKLIST=1 ExtUtils::MakeMaker incantation.

[ssurbhi560]

Thanks John for letting me know about this. I am still quite new to this and all this was something I didn't know, so I ended up adding everything I found useful. But as you said this documentation would be used by someone already well versed with Perl packages so it would probably be irrelevant for them.

So, now, @kathatherine and @jmarshall what would you suggest - should I remove the all the information about Module::Build or may keep a sentence describing what Module::Build is and examples of recipes using perl-module-build?

[kathatherine]

@ssurbhi560 At least one link to some information on Module::Build would be good, in my opinion, just for people who are newer to it. It could be useful to someone, even if the audience for this section is people who are more experienced in Purl. But as @jmarshall says, the most important thing is explaining how users can use Module::Build in the build section of their yaml instead of ExtUtils::MakeMaker. So a section like lines 1561 - 1574, just below that section, with the necessary Module::Build information instead. Am I correct, John?