Support Clarity language changes in Stacks 2.1

[obycode]

With the switch to 2.1, we have the opportunity to make some breaking changes to the language. It would make sense to put together a formal specification of the language, including some breaking changes (e.g. limitations on symbol names like this<is>con/fus!ing*). It would be nice to have a BNF specification (or something else). The new parser (see hirosystems/clarity-repl#74) will implement these changes.

The task to define the language specification has been moved to stacks-network/stacks-core#3052. This issue should track that issue and make the corresponding changes in the REPL parser.

[fariedt]

I don't have a BNF, but I came up with this using instaparse a few months ago, and it works for pretty much everything I've thrown at it. I had to strip comments, though.

[LNow]

@obycode I think this discussion should be started in stacks-blockchain repo, as this is where new language functions are added. For sure we need some form of specification to eliminate weirdness I described here: stacks-network/stacks-core#2696 And unfortunately repl will should support both old and new specification.

@fariedt this looks awesome!!!

[obycode]

Agreed. Sounds good to me. I opened stacks-network/stacks-core#3052 and will modify this issue to track that issue and make the corresponding changes in the REPL.

[lgalabru]

@obycode now that everything lives on the stacks-blockchain side, can we close this issue?