(define (save f)
  (let loop ((env (filter pair? (procedure-environment f)))
             (src (procedure-source f)))
    (if (null? env)
        (begin
         (write src)
         (newline))
        (loop (cdr env)
              `(let ,(zip (caar env) (cdar env)) ,src)))))

(define (save f)
  (write (fold (lambda (bs acc)
                  (cond
                    ((list? bs) `(let ,(zip (car bs) (cdr bs)) ,acc))
                    ((pair? bs) `(let ((,(car bs) ,(cdr bs))) ,acc))
                    (else acc)))
               (procedure-source f)
               (procedure-environment f)))
  (newline))

(define (save f)
  (let ((env (filter pair? (procedure-environment f)))
        (src (procedure-source f)))
    (write (fold (lambda (bs acc)
                    (cond
                      ((list? bs) `(let ,(zip (car bs) (cdr bs)) ,acc))
                      ((pair? bs) `(let ((,(car bs) ,(cdr bs))) ,acc))
                      (else acc)))
                 src env))
    (newline)))

(define (save f)
  (let loop ((env (procedure-environment f))
             (src (procedure-source f)))
    (cond
     ((null? env)
      (write src)
      (newline))
     ((pair? (car env))
      (let ((keys (caar env))
            (vals (cdar env)))
        (loop (cdr env)
              `(let ,(if (list? keys) (zip keys vals)
                                      `((,keys ,vals))) ,src))))
     (else
      (loop (cdr env) src)))))

(define (save f)
  (let loop ((env (filter pair? (procedure-environment f)))
             (src (procedure-source f)))
    (if (null? env)
        (begin
         (write src)
         (newline))
        (let ((keys (caar env))
              (vals (cdar env)))
          (loop (cdr env)
                `(let ,(if (list? keys) (zip keys vals)
                                        `((,keys ,vals))) ,src))))))

(use-modules (srfi srfi-1))
(define (save f)
  (let ((env (filter pair? (procedure-environment f)))
        (src (procedure-source f)))
    (write `(let ,(concatenate (map (lambda (p) (if (list? p) (zip (car p) (cdr p)) (list (list (car p) (cdr p))))) env)) ,src))
    (newline)))

;; tests:
(define (foo x y) (lambda (a b) (lambda (c d) (+ x y a b c d))))
(define bar ((foo 1 2) 3 4))

;; guile> (save (let ((z 15)) (let ((y 14)) (lambda (x) (+ x y)))))
;; (let ((y 14) (z 15)) (lambda (x) (+ x y)))
;; guile> (save (let ((y 14)) (lambda (x) (+ x y))))
;; (let ((y 14)) (lambda (x) (+ x y)))
;; guile> (save (let ((y 14) (z 15)) (lambda (x) (+ x y))))
;; (let ((z 15) (y 14)) (lambda (x) (+ x y)))
;; guile> (save bar)
;; (let ((a 3) (b 4) (x 1) (y 2)) (lambda (c d) (+ x y a b c d)))

(define (save f)
  (let loop ((env (filter pair? (procedure-environment f)))
             (src (procedure-source f)))
    (if (null? env)
        (begin
         (write src)
         (newline))
        (let ((keys (caar env))
              (vals (cdar env)))
          (loop (cdr env)
                `(let ,((if (list? keys) zip list) keys vals) ,src))))))