cons、car与cdr的实现

(define (cons a b)
  (lambda (f) (f a b)))

(define (car c)
  (c (lambda (a b) a)))

(define (cdr c)
  (c (lambda (a b) b))

> (car (cons 1 2))
1
> (cdr (cons 2 3))
3

var cons = function(a, b) { 
    return function(f) { 
        return f(a, b) 
    } 
}

var car  = function(c) { 
    return c(function(a, b) { 
        return a 
    })
}

var cdr  = function(c) { 
    return c(function(a, b) { 
        return b
    })
}

>> car(cdr(cons(1, cons(2, 3))))
>> 2