ABNF support

[MaxDesiatov]

I would like to be able to parse Dhall, which provides an ABNF grammar. As far as I understand, ABNF is more standardized, so I wonder how hard would it be for Covfefe to support it?

[palle-k]

I will look into it. From a first look at ABNF, it doesn't look too hard.

Note that the parsers that Covfefe provides don't have amazing performance and depending on the type of grammar you're working with, LL or LR parser implementations will likely perform better.

[palle-k]

I've released a new version that has ABNF support. I have tested it with the Dhall grammar.

[MaxDesiatov]

@palle-k that's amazing, thank you!