Developer's Corner

This page contains documentation and links related to the maintenance and development of the Perl Data Language.

TOC

Development Ideas

This is meant to be a collection of ideas currently floating around the PDL mailing list for current and future development.

All, I've consolidated the topics and discussion from perldl and pdl-porters from the past few weeks as part of an effort to produce a PDL way forward draft. It still needs some corrections to wiki as well as some reorganization.

However, the summary list should, at least, be a single place to look for the ideas and consensus as I saw it forming. I see this as a scratch page of specific tasks to move forward with PDL.

The list is long but there are some major thoughts and key ideas that stick out:

1. General Thoughts
2. Modularize PDL
3. Better Handling of External Dependencies
4. Provide a Baseline Default 2D and 3D Graphics Capability
5. Documentation and Usability Fixes
6. Build Process Fixes
7. Computational Improvements
8. Padre Development for Strawberry Perl Pro Release
9. Coordinate PDL Plans with Perl6

Accessing the latest from Git

The first step in developing PDL is getting the source files from the Git repository on Sourceforge. To begin, you should install Git. Once you've done that, go to an appropriate directory and issue this command:

git clone git://pdl.git.sourceforge.net/gitroot/pdl/pdl

After running this command, you should have a copy of the current state of PDL in a subdirectory named pdl. You can then edit the files as you like. As you are going along, you should regularly commit your changes to your local repository by issuing a command like this:

git commit -a

at which point you will be put into your normal text editor so that you can explain what it is you've done so far. You should give a one-line summary of what this commit contains, followed optionally by more verbose paragraphs explaining some of the details. You should probably also occasionally check for any recent updates from other developers by pulling from the repository on sourceforge with a command like this:

git pull

I could go into further details, but I believe that most of this (and much more yet to be added) should be put into a PDL-Git best-practices page, so I will hold off for now.

Pushing commits

Note that if you have developer access and you want to push your most recent work back to the repository at Sourceforge, you will need to set up your local repository's remote-configuration option to use the ssh protocol. A command along these lines should work:

git config remote.origin.url ssh://[email protected]/gitroot/pdl/pdl

Modifying the Website

As of April 2022, pdl.perl.org is hosted by GitHub Pages from github.com/PDLPorters/pdlporters.github.com. See their docs for how to operate this.

As a temporary measure, there are redirecting HTML pages under PDLdocs/ with <link rel=canonical> to tell Google to use MetaCPAN pages instead. Once Google searches for e.g. whistogram stop giving hits for pdl.perl.org those can safely be removed.

Survey Results

Read the Results from the Fall 2009 Usage and Installation Survey.

Building SciPDL for Release

This section is for Matt and other Mac OS X PDL users/developers to document the recipe for building SciPDL for a new PDL release. Ideally, following these instructions would allow another PDL developer with a Mac OS X platform to build a new SciPDL package for release.

Checking Dependencies with Devel::CheckLib

Dependency checking is a critical component of the build process for PDL where many of the submodules depend on external libraries to provide needed functionality. We would like to move to a common framework for dependency detection that this platform independent and robust.

Devel::CheckLib looks like a promising approach. The idea is that Devel::CheckLib implements checks for libraries, include files, and functionality by compiling test programs with candidate options and verifying that they build and run. To this end, the current release of Devel::CheckLib is bundled with the PDL release to support checks without additional required external dependencies.

Sorting files based on last commit date

Portions of PDL have not been modified in a long time, in some cases a decade or more. The following command (in a bash shell from the top of the PDL git repository) sorts all the files in the tree by the date of last commit. You might find something you never knew was in there! (note: this may take some time to run because git, unlike cvs, does not keep track of files, but of commits, so there is not (to my knowledge) a one-off way to do this).

git ls-tree -r --name-only HEAD | while read filename; do echo "$(git log -1 --format="%ai" -- $filename) $filename"; done | sort -r