Ask HN: Best way to document a new language's grammar?

[zMiller]

Hey,

I'm in the process of writing the documentation for customer facing grammar (built using nearly.js) to allow for 'easy' querying of an API by the average Joe.

I was thinking of actually writing a GraphQL schema for the language's grammar and 'flattening' it out into a static page. Added plus is the schema can be used for autocomplete like behavior in a moded Graphiql IDE.

What documentation tools have you used in the past to document a language's grammar ? Would love your thoughts and feedback on how bad this idea is. Thanks !