; Original function mame: multirember&co
(define (multico a lat col)
  (cond
     ((null? lat) (col '() '()))
     ((eq? (car lat) a)
      (multico a
               (cdr lat)
               (lambda (newlat seen)
                  (col newlat
                  (cons (car lat) seen)))))
     (else
      (multico a
               (cdr lat)
               (lambda (newlat seen)
                  (col (cons (car lat) newlat)
                  seen))))
     )
  )


; An usage example of multico:
(define menu '(ham tuna beer tuna beer))
(define (count1 x y) (length x))
(multico 'tuna menu count1) ; Output: 3

def splitmap(el, sequence, process):
    l1 = []
    l2 = []
    for x in sequence:
        if el == x:
            l2.append(x)
        else:
            l1.append(x)
    return process(l1, l2)

menu = "ham tuna beer tuna beer".split()
count1 = lambda x, y: len(x)
print splitmap("tuna", menu, count1)

def splitmap(el, sequence, process):
    l1, l2 = [], []
    for x in sequence:
        ((l1, l2)[el == x]).append(x)
    return process(l1, l2)

def splitmap(el, sequence, process)
    process sequence.split{|x| x==el}
end

def splitmap(el, seq, coll):
  if not seq:
    return coll([], [])
  elif seq[0] == el:
    return splitmap(el, seq[1:],
       lambda s1, s2: coll(s1, seq[0:1] + s2))
  else:
    return splitmap(el, seq[1:],
       lambda s1, s2: coll(seq[0:1] + s1, s2))

import sys
from random import randint
from memory import memory
sys.setrecursionlimit(10000)
print memory() # 1.7 MB
seq2 = [randint(1, 5) for _ in xrange(2000)]
def count12(x, y):
    print memory() # 18 MB
    return [len(x), len(y)]
print splitmap(2, seq2, count12)

(define (splitter x seq l1 l2)
  (cond
     ((null? seq) (cons l1 (cons l2 '())) )
     ((eq? (car seq) x)
      (splitter x
               (cdr seq)
               l1
               (cons (car seq) l2)
               ))
     (else
      (splitter x
               (cdr seq)
               (cons (car seq) l1)
               l2               
               ))
     )
  )

(define (multico2 a lat col)
  (apply col (splitter a lat '() '())))

(define menu '(ham tuna beer tuna beer food))
(define (count1 x y) (length x))
(multico2 'tuna menu count1) ; Output: 3

>They had one of the museum's 'scientists' standing next to Adam and Eve's animatronic pet baby T-Rex and explaining that there was no problem with the exhibit since dinosaurs didn't eat meat before the Fall of Man. Presumably the knife-edged teeth were for particularly tough mango skins.<

The venerable master Qc Na was walking with his student, Anton. Hoping to prompt the master into a discussion, Anton said "Master, I have heard that objects are a very good thing - is this true?" Qc Na looked pityingly at his student and replied, "Foolish pupil - objects are merely a poor man's closures."

Chastised, Anton took his leave from his master and returned to his cell, intent on studying closures. He carefully read the entire "Lambda: The Ultimate..." series of papers and its cousins, and implemented a small Scheme interpreter with a closure-based object system. He learned much, and looked forward to informing his master of his progress.

On his next walk with Qc Na, Anton attempted to impress his master by saying "Master, I have diligently studied the matter, and now understand that objects are truly a poor man's closures." Qc Na responded by hitting Anton with his stick, saying "When will you learn? Closures are a poor man's object." At that moment, Anton became enlightened.

(define (make-rat n d)
  (let ((g (gcd n d)))
    (cons (/ n g)
          (/ d g))
    )
  )