Include rail-road grammar diagrams to compliment the ABNF

[ocharles]

Include rail-road grammar diagrams to compliment the ABNF

[ocharles]

I note with things like https://ocharles.org.uk/dhall-grammar.html#simpleLabel that it doesn't distinguish between things that shouldn't parse - that whole reserved block is a look-ahead that must fail, so it shouldn't show up here. This might suggest a separate grammar, like the ABNF, that can actually be read by GrammKit (or replacing the ABNF by something else).

[ocharles]

I see dundalek/GrammKit#9 discusses that exact issue, and they are working out potential improvements. It turns out the negative look ahead is shown, but the double vertical lines is a bit too subtle.

[Gabriella439]

Yeah, I think this is a good idea. An appropriate place to host this is underneath the reference subsection of the Dhall wiki:

https://github.com/dhall-lang/dhall-lang/wiki

[Gabriella439]

Actually, you don't even need to "host" it there per se. You can just have the wiki link to wherever you host it (i.e. on your site or in the dhall-js project if you prefer).

[ocharles]

It'd be nice to remove an indirection and have it directly on the wiki. I think GrammKit can generate Markdown, so I'll explore that. I will probably have to host the images externally, if it generates them, but I'm fine with that.

[ocharles]

I also wonder if it should be checked it, and versioned in parallel with changes to the ABNF file.

[Gabriella439]

Yeah, you can feel free to check it in. The place it would go is underneath the standard/ directory since it is another presentation of the standard grammar

[ocharles]

Cool, assign this to me and I'll get a PR up.

[ocharles]

I'm unlikely to get round to fixing this. Sorry all! Closing for now.