Using shlex to sanitize dowmload_handler()
Almost complete refactoring using classes
Everything seems to work
A first complete version of greg.py after a refactoring into classes
Adding 2013 to the header
Adding PKGBUILDs to the repo.
A much more complete support of tagging
substitute_placeholders()
Default date in format YYYY-MM-DD
I'm not using islice
2013 in gregparser.py
AttributeError in line 226
The new tagging functionality mostly works
Deleting debugging prints
Pacman 4.1 Changes

As I wrote on AUR:

Added some optdeps, since you added the option for download handlers
Added the pkgver function for the new versioning handling
I did not add python, as in my paste.
build got renamed to package and the git-stuff removed, as it is not necessary anymore
Removed provides and conflict

Those aren't necessary. Especially provides. It is greg, so it's not necessary to say it is greg.
Conflict could remain, but as it is added to the git pkgbuild also not necessary. As the git version will always conflict with stable-greg
Merge pull request #9 from Narrat/patch-1

Pacman 4.1 Changes
Merge pull request #10 from Narrat/patch-2

Removed provides and conflict
Subdirectory names admit placeholders too
Fixed a bug in download()