Currently, this is a 'blind idiot port' of pyabc. It isn't perfect, and not everything in the original repo was ported.
A lot of code isn't clean because C# isn't very pythonic, and many pieces of code were transcribed as they were.
While I like pyabc, as of my writing it is in 'Pre-Alpha' and is something of a hybrid lexer/parser, I'd like to push it the extra mile and make ABCSharp an actual lexer/parser instead of the hybrid it currently is.
I'll likely keep a 'pyabc port' branch for posterity's sake.
But; it seems ABC's grammar can be confusing;
% is a comment
%% is a stylesheet derective
And while the official documentation is very verbose, it no longer provides obvious grammar diagrams (the two BNF diagrams listed are no longer available), making it harder to write a full parser without extensive knowledge of the format.
But perhaps the worst problem, is that the format has a few intended uses; and a catch-all parser is likely too much for me to handle.
I'm not a legal expert, but the original is licensed under the MIT License; and the source can be found here. As required, a copy of their license has been added to the repo.