Scheme debugger support

[ma-chengyuan]

MIT Scheme has a debugger which can be entered by typing (debug) after an error:

1 ]=> something

;Unbound variable: something
;To continue, call RESTART with an option number:
; (RESTART 3) => Specify a value to use instead of something.
; (RESTART 2) => Define something to a given value.
; (RESTART 1) => Return to read-eval-print level 1.

2 error> (debug)

There are 5 subproblems on the stack.

Subproblem level: 0 (this is the lowest subproblem level)
Expression (from stack):
    something
Environment named: (user)

The execution history for this subproblem contains 1 reduction.
You are now in the debugger.  Type q to quit, ? for commands.

3 debug>

Then I can use commands to inspect the call stack or environments, which can be really helpful.

Is there any way to access this nice feature in conjure? Typing (debug) in my buffer and ,ee it to the REPL doesn't seem to work.

[Olical]

Oh neat, I think this would tie into #182 where I would like to hook into other Neovim stepping debugger plugins. This is essentially on hold until I start to get Fridays off work again or something since it's a sizeable project I don't have the time / mental capacity for right now.

Basically I want to expose a general debugging interface for clients (like scheme and clojure) to integrate with which would plug into some other really neat interactive debugger plugin for Neovim.