man Padre::Manual::Hacking (3): Guide to hacking on Padre

DESCRIPTION

This is the Padre Developers Guide.

It is intended for people interested in hacking on Padre, and specifically hacking the core distribution.

Getting Started

This document assumes that you are working from a copy of Padre checked out from the official repository.

Rather than just checking out the Padre distribution alone, we recommend that you checkout the entire repository trunk, which will provide you with Padre itself, miscellaneous tool scripts, and most of the plugin distributions as well.

The specific path you want to check out is...

  http://svn.perlide.org/padre/trunk

Extra Files

The trunk contains primarily a set of directories, one for each CPAN distribution created for Padre by the development team.

In addition, there are some additional scripts that are for development purposes and are not part of the releases themselves.

Padre/dev

This is a launch script used to start Padre in developer mode. This mainly automates a couple of conveniences, such as using a local .padre directory instead of your system one, and including lib in the @INC path to prevent needing to run make constantly.

tools/release.pl

Used to release Padre.

tools/update_version_number.pl

Similar to the ppi_version tool from CPAN, this updates the version number.

Bug Tracking

Padre uses Trac for bug tracking.

The main web site of Padre is actually its Trac <http://padre.perlide.org/>

Patching

Check out the trunk (<http://svn.perlide.org/padre/trunk/>) and use svn diff to create your patch while your current working directory is the trunk directory.

Please send patches either to the padre-dev mailing list or add them to trac to the appropriate ticket.

Branching

Usually we use the trunk for all the development work so we can see issues and fix them quickly. At least some of us already use Padre for the development work running it from the workspace so if someone breaks trunk that will immediately affect some of the developers.

So please don't intentionally break the trunk!

If you think your change is relatively large and you feel more comfortable working on a branch, do it.

Change Management

We try to work with small changes. There are no exact rules what is small and what is already too big but we try not to mix unrelated issues in one change. If you need a styling change or white space change, do it it in a separate commit.

Commit messages are important. If a commit relates to a ticket please try to remember adding the ticket number with a # sign ( #23 ). The GUI of Trac will turn it into a link to the relevant ticket making it easier to find related information.

Most of the current major committers monitor the commit messages to see what everyone else is doing, so please write them as if they are going to actually be read within a few hours of you making the commit.

Tickets/Issues/Bugs

We are using Trac as the issue and bug tracker.

When adding a note that relates to one of the commit in SVN please use the r780 format. That allows Trac to create links to the diff of that revision.

Code review

We don't have formal code-review but in response to the commit messages we sometimes reply with comments to the padre-dev mailing list.

You are also encouraged to do so!

STYLE

We're not overly strict about code style in Padre (yet), but please don't feel offended if somebody corrects your coding style.

There are a number of relatively simple preferences that are more or less enforced, but none of this is automated. We prefer humans over automation for this because PerlTidy has something of a history of doing things overly strictly, which can sometimes destroy clarity for the sake of correctness.

In general, the code style preferences for Padre are guided by ease of understanding code, and thus ease of maintenance.

Tabs instead of Spaces

Use one tab character for each indentation level at the beginning of a line.

There are a lot of people working on Padre, with indent preferences ranging from two to eight spaces. Using tabs allows all of the development team to work with code at the indent level that is most comfortable for their eyes.

In particular, allowing the use of large (eight or higher) tabs enables developers with visual processing or eye-sight issues (astygmatisms, mild short-sightedness, figure-ground problems) to effectively contribute to Padre.

If your editor doesn't support tabs properly, well that's clearly a temporary probably because you will eventually be switching to Padre, which DOES support tabs properly.

Additionally, there current plan for project support does include correctly supporting project specific tab-versus-space settings, so you can use spaces for your code, and Padre will just switch and Do The Right Thing when you work on the Padre project.

After the initial indentation, do not use tabs for indentation any more. Instead, use the appropriate amount of spaces to make things line up.

Example: (Where you put the opening brace isn't
important for this example!)

  sub baz {
          if (foo()
              and bar())
          {
                  # ...
          }
  }

Method and Subroutine Naming

Methods in Padre itself must be lowercase, and should generally consist of complete words separated by underscores. (e.g. Use ->check_message instead of ->chkMsg).

Methods in all capitals are reserved for Perl-specific methods such as "DESTROY"

Methods in StudlyCaps are reserved for the Wx bindings.

Separating This allows us to be clear which methods (or overrided methods) are part of the Wx layer, and which are part of Padre itself.

Accessors

If a value is set once during the constructor and then not changed afterward, use a accessor name which matches the original parameter.

  my $object = Class->new(
      value => 'something',
  );
  
  sub value {
      $_[0]->{value};
  }

Accessors which can change post-constructor should be named ``get_foo'' and ``set_foo''. Do not use mutators.

For simple accessors, we encourage the use of Class::XSAccessor for accessor generation. This not only makes them significantly faster, but also makes debugging easier, because the debugger won't descend into every single accessor sub.

HEAVY-DUTY DEBUGGING

Don't bother reading this sectionif you don't know any C or if you just want to get started hacking Padre!

If you're planning to do a serious debugging session, you may want to set up Padre with a debugging perl and debugging version of Wx. Particularly the core developers are encouraged to have a go at this because the debugging version of wxWidgets will show various warnings of failed assertions which may otherwise go undetected. This is a bit of work to set up and not very useful for a casual hacker as this will involve compiling your own perl, wxWidgets, and Wx.

Here's a rough how-to for Linux and similar OSs:

Building your own debugging perl

Get the perl sources from http://cpan.org/src/README.html or via git. As of this writing, perl 5.12.1 is the latest stable release.
Extract the sources and run
```
  ./Configure -Dprefix='/path/for/your/perl' -DDEBUGGING -Dusethreads -Duse64bitall -Dusedevel -DDEBUG_LEAKING_SCALARS -DPERL_USE_SAFE_PUTENV
```
Remove the "-Duse64bitall" if you have a 32bit OS (or machine). Keep answering the questions with default (hit Enter) except for the question about additional cc flags. Here, put the default settings that are suggested in the [...] brackets and add two options:
```
  -DDEBUG_LEAKING_SCALARS -DPERL_USE_SAFE_PUTENV
```
Afterwards, keep hitting return until the configuration is done.
Compile "perl" by typing "make" or for multiple CPUs, type "make -jX" where X is the number of CPUs+1.
If all went well, type "make install" to install your own private debugging perl.
Check whether the executables in /path/to/your/perl/bin all contain the version numbers of perl. You may want to create symlinks of the basename. If so, cd to the directory and run:
```
  perl -e 'for(@ARGV){$n=$_;s/5\.\d+\.\d+//; system("ln -s $n $_")}' *5.*
```
Check that there's now also a perl symlink to perl5.12.1 (or whatever version of perl you built).
Setup the environment of your shell to use the new perl. For bash-like shells, do this:
```
  export PATH=/path/to/your/perl/bin:$PATH
```
csh like shells probably use something like "setenv" or so.
Try running "perl -V" to see whether your new perl is being run. (See also: "which perl")
Make sure "perl -V" shows these particular ``compile-time options'':
```
  DEBUGGING DEBUG_LEAKING_SCALARS PERL_USE_SAFE_PUTENV
  PERL_USE_DEVEL
```
There'll certainly be others, too.

Building your own debugging wxWidgets

Make sure your ~/.cpan is owned by you and not being used by another perl. Maybe clean up ~/.cpan/build/* so there's no collisions.
Run cpan. (NOT as root!)
If you like, install "Bundle::CPAN" for convenience. Potentially restart cpan afterwards. Check whether the modules were installed into your fresh perl at /path/to/your/perl/lib.....
From cpan, type "look Alien::wxWidgets". You should get a new shell in an extracted "Alien::wxWidgets" distribution.
Build wxWidgets by running:
```
  perl Build.PL --debug --unicode
```
Hopefully, it won't say you're missing any dependencies. If you're missing any, quit the shell and install them from the cpan shell before continuing.
"Build.PL" will ask you whether you want to build from sources. Yes, you do. Have it fetch the sources as .tar.gz.
```
  ./Build
  ./Build test
  ./Build install
```

Installing a debugging Wx.pm

Now, you want to set up your own Wx.pm with debugging enabled. First, install the prerequisites for Wx. I did it like this:
```
  cpan> look Wx
  ...
  $ perl Makefile.PL
  ... blah blah missing this or that ...
```
Take note of the missing dependencies, exit to the CPAN shell, install the missing modules, then "look Wx" again.

If you have all Wx.pm dependencies in place, build "Wx" like this:

  perl Makefile.PL --wx-debug --wx-unicode
  make
  make test
  make install

Installing Padre from SVN

Once Wx.pm is installed, check out Padre from the Subversion repository and cd to its directory under trunk/Padre.
Run "cpan ." to automatically install all dependencies of Padre!
Run the following to set up Padre:
```
  perl Makefile.PL
  make
```
Run dev to start Padre from your checkout.
```
  perl dev
```
or with all plugins loaded:
```
  perl dev -h
```
or with the Perl debugger:
```
  perl dev -d
```
Don't be annoyed by the Wx popups complaining about assertion-failures. They indicate potential bugs that probably need attention. If you get these, that means it was worth the effort to build a debugging perl and Wx! Note that the stack backtraces given are at the C level, not Perl backtraces.

SUPPORT

For support with Padre itself, see the support section in the top level Padre class.

For support on hacking Padre, the best place to go is the #padre channel on <irc://irc.perl.org/>.