Add package.el builder & packages

[the-kenny]

Nixpkgs already had some Emacs packages included. As of today, many new (and existing) packages are distributed via package.el, either on GNU ELPA or Marmalade.

This pull requests implement a new builder (buildEmacsPackage) for package.el packages which integrates nicely with Nix. In order to correctly set the package-directory-list variable in Emacs, it adds some code to the site-start.el file (9db63bf) which checks the environment variable EMACS_PACKAGE_EL_PACKAGES for directories. This variable is set by the setup-hook of Emacs.

The other addition is a script to generate package expressions from generic package.el repositories. This enables us to automatically import all available packages from the popular repositories and distribute them with Nix. Included in this pull request is the generated file for GNU ELPA and Marmalade, which are the most popular repositories for stable releases.

The whole result also plays nicely with the existing emacs packages in Nix: They can even depend on each other.

My intention for all this was to get more familar with nix and the way packages are built, used, and integrated. Another reason was the ability to automatically test package.el packages via Hydra, which might be useful for some personal projects for me.

I don't know what you guys think about all this, and I'm happy for any feedback. Positive or negative.

[peti]

I'm not very familiar with packag.el, but from what little I can tell your improvements look really nice.

[the-kenny]

Started running tests on my own hydra instance on http://hydra.tarn-vedra.de. There are some (smaller) issues where the code to build the packages isn't robust enough to handle errors. I'll probably have to do a bit more testing before this is clear to merge.

[the-kenny]

Any comments on this? If you guys are ok with adding ~990 packages to Nix I think this should be ready to merge. If it's too much spam, we could remove the recurseIntoAttrs so the packages won't be listed in nix-env -qa.

I want to do a single more commit before a merge (updating all packages), so please don't click merge already.

[mornfall]

Count me in. :-) Just saying.

[peti]

I think your changes should be merged as soon as you think they're ready. If there is some unexpected issue, then it's cheap to revert (or fix) the commit anyway, so there's very little risk associated with this update.

[the-kenny]

I just pushed a final update to the automatically generated package list.

This should be ready for merge now. Sorry for the long (10 days) delay from my last communication. I just lost some focus...

One thing to mention is that I added a recurseIntoAttrs to the emacs24Packages stuff, so they appear in nix-env -qa '*'. I'm not sure if this causes other side effects (will hydra try to build the packages?). If it does, I'm totally fine with removing that call and forcing the user to use nix-env -iA pkgs.emacs24Packages.${bla}

[the-kenny]

Merged master and fixed a small conflict with the recently added `ess' package. Should be a clean merge with master now.

Current state is building at http://hydra.tarn-vedra.de/eval/137

[peti]

The package ess is at version 13.05 at http://ess.r-project.org/, but the package you've generated claims to be version 5.14. How is it possible that these two versions differ so significantly?

[the-kenny]

That's because someone uploaded a very old version to Marmalade:
http://marmalade-repo.org/packages/ess

This is kind of problemaic - I hoped that packages people upload there are
pretty recent.

On Thu, Jul 25, 2013 at 10:25 AM, Peter Simons notifications@github.comwrote:

The package ess is at version 13.05 at http://ess.r-project.org/, but the
package you've generated claims to be version 5.14. How is it possible that
these two versions differ so significantly?

—
Reply to this email directly or view it on GitHubhttps://github.com//pull/664#issuecomment-21539679
.

[the-kenny]

@peti Above commits contains some logic to automatically use the more recent version (as determined by versionOlder) of emacs packages. Thanks for uncovering this bug for me.

[the-kenny]

Closing this for now, I'll come up with a new PR as soon as I resolve the outstanding issues (e.g. mirroring old versions not available in repo anymore)