Debugging REPL

Hello all,

for debugging, I want to start a REPL inside a procedure so that the
lexical bindings inside the procedure are available.

For example, if anything goes wrong in this procedure:

(define (f x)
  (let ((sq (* x x)))
    (+ sq sq)))

I would like to be able to change it to

(define (f x)
  (let ((sq (* x x)))
    (debug-repl)
    (+ sq sq)))

and run it again. A REPL should be started in which I can access x and
sq. Is this somehow possible?
I couldn't figure out how I can make the lexical bindings accessible.
Somehow the current environment would need to be accessed, wouldn't
it?

Best regards
Daniel Sadilek

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