Run-length encoding of a list

	;; P10 (*) Run-length encoding of a list.
	;; Use the result of problem P09 to implement the so-called run-length encoding data compression method. Consecutive duplicates of elements are encoded as lists (N E) where N is the number of duplicates of the element E.
	;; Example:
	;; * (encode '(a a a a b c c a a d e e e e))
	;; ((4 A) (1 B) (2 C) (2 A) (1 D)(4 E))
	#lang racket
	(provide encode)
	(require srfi/1)
	(define (encode lst)
	(let loop ((lst lst) (acc '()))
	(if (null? lst)
	(reverse acc)
	(loop (strip lst)
	(cons
	`(,(length (picks lst)) ,(car lst))
	acc)))))
	(define-syntax define-encode-aux
	(syntax-rules ()
	((_ name proc)
	(define (name lst)
	(let ((head (car lst)))
	(proc (lambda (x)
	(eq? head x)) lst))))))
	;; Using a procedure, take-while, defined in SRFI-1
	(define-encode-aux picks take-while)
	;; Using a procedure, drop-while, defined in SRFI-1
	(define-encode-aux strip drop-while)

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