Is there an existing issue for this?

• I have searched the existing issues

What is the missing lexer?

I would like to have a lexer for CSV (comma separated value) files:
https://en.wikipedia.org/wiki/Comma-separated_values

One possible way could be to base the lexer on https://www.ietf.org/rfc/rfc4180.txt.

Links to existing syntax definitions

https://github.com/antlr/grammars-v4/blob/master/csv/CSV.g4