From: Arne  Hanssen
Subject: Usage of lambda
Date: Fri, 13 Oct 2006 18:06:29 +0000
Message-ID: <arne.hansenNOSPAM-2A44D9.20062913102006@amsnewsfe05.chello.com>

In scheme these are valid functions:
(define (cons a d)
   (lambda (x)(x a d)))

(define (car x)
   (x  (lambda (a d) a)))

If I try redo the same functions in Common Lisp I get an error 
when running car1. The error being:

  CAR1: symbol D has no value
    [Condition of type SYSTEM::SIMPLE-UNBOUND-VARIABLE]

The CL code I try to run is this: 

(defun cons1 (a d)
   (lambda (m) (m a d))) 

(defun car1 (x) 
   (x (lammda (a d) a))) 

(car1 (cons1 'a 'b)) 

regards 
-arne

From: Pascal Costanza
Subject: Re: Usage of lambda
Date: Fri, 13 Oct 2006 18:34:48 +0000
Message-ID: <4pa4i0Fht80kU1@individual.net>

Arne Hanssen wrote:
> In scheme these are valid functions:
> (define (cons a d)
>    (lambda (x)(x a d)))
> 
> (define (car x)
>    (x  (lambda (a d) a)))
> 
> If I try redo the same functions in Common Lisp I get an error 
> when running car1. The error being:
> 
>   CAR1: symbol D has no value
>     [Condition of type SYSTEM::SIMPLE-UNBOUND-VARIABLE]
> 
> The CL code I try to run is this: 
> 
> (defun cons1 (a d)
>    (lambda (m) (m a d))) 
> 
> (defun car1 (x) 
>    (x (lammda (a d) a))) 
> 
> (car1 (cons1 'a 'b)) 

(defun cons1 (a d)
   (lambda (x) (funcall x a d)))

(defun car1 (x)
   (funcall x (lambda (a d) a)))


If you want to know why you have to say funcall here, google for 
"Lisp-1" and "Lisp-2".


Pascal

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