grammar

It would be great to see a tutorial on how to port a pyparsing based project to Lark.

The rust code in the .lalrpop files are still on rust 2015 and need to be manually updated since cargo fix won't work on those files.

We should also update the generated code to emit 2018 idiomatic code (see #2018 )

It's currently just a sequence, which is not necessary.

Tokenizer.pipe, Rules.suggest and maybe some other methods should return an iterator instead of a Vec<_> for more flexibility.