Sometimes, it amazes me how elegant Python is. A class system that is almost as powerful as CLOS, yet easy to use and comprehend. It is truly one of the most powerful programming systems in the world, if you show it a bit of love.
I have developedĀ a lot of metaclasss code when designing PISI. It has made the XML processing (which is managed by the autoxml library I wrote) and CLI code exceptionally cool. I was making someĀ cleanup for the next PISI release, and I happened upon a not so pleasantĀ Constants class, which now looks great thanks to metaclasses:
Well, and what did I find particularly elegant? How easy it was to write the constantsingleton metaclass, and how I tested it, almost poetic.
Mind you, python 2.x is still problematic with metaclasses, I think you should be using python 3.x if you want to use them. I just had to deal with a meaningless error that vanished without any reason in 2.7.13, so please use these classes at your own risk! And do not forget to link toĀ the PISI github and mind the license, which is GPL-3.0 for theseĀ files. I have written theseĀ useful tests for that annoying stability problem, though, so please do not forget to first test it in your unit test environment first.
Happy hacking!