emacs mode

[jonsterling]

We'll want an emacs mode with the following to start:

• syntax highlighting
• a way to execute a signature

We can try and bring the old emacs mode up to date, though we'll have to remove some features from it until Red JonPRL catches up.

Longer-term, I'd like to have some kind of server interface, so that we can do things like just re-elaborate a single declaration, remembering the results of the previous unchanged declarations.

I suggest that we should let the emacs mode live in this repository, so that it can be updated every time a change to Red JonPRL is made.

[jonsterling]

The other thing we should consider is whether we can have a richer display by giving some kind of structured data to Emacs rather than whatever we decided to print.

[jonsterling]

We've got a very rudimentary emacs mode that supports highlighting; an org-babel language thing is also present, which is what I'm currently using to interactively elaborate Red JonPRL signatures.