From: Raja Sooriamurthi
Subject: Re: power set implementation?
Date: Fri, 01 Nov 1991 15:46:58 +0000
Message-ID: <raja.689010418@copper>

>Is there a primitive in CL that computes power set of some given set?
>Has anyone implemented it? I would like to get one.

Heres a simple version in Scheme:

(define power
  (lambda (s)
    (if (null? s)
	'(())
	(let ([t (power (cdr s))])
	  (append (map (lambda (x) (cons (car s) x)) t)
	    t)))))
- R.