Add Full BNF Grammar
We currently extend the SQL-92 grammar within the spec and have BNF elements to describe those extension. The Kotlin implementation uses a hand coded lexer/parser (a decision which was purely a pragmatic one when we first built it). We should have a full BNF (or equivalent) for PartiQL in the specification.
May I suggest an ANTLR4 grammar?
It is a very reasonable suggestion and I think ANTLR4 is probably the strongest contender here, though I do want to keep our options open (e.g. maybe some form of PEG).
I would love to see Lemon compatible grammar so that I could use it together with Sqlite, but ANTLR4 is also great option.