Zebra puzzle: Difference between revisions
Content deleted Content added
→{{header|C}}: code format to fit in window |
Add Racket entry |
||
Line 1,553:
Smoke: PallMall BlueMaster Blend Dunhill Prince
Pet: Bird Dog Horse Cat Zebra</pre>
=={{header|Racket}}==
{{trans|Prolog}}
<lang racket>
#lang racket
(require racklog)
(define %select
(%rel (x xs S S1)
[(x (cons x xs) xs)]
[(x (cons S xs) (cons S S1)) (%select x xs S1)]
[((cons x xs) S)
(%select x S S1)
(%select xs S1)]
[('() (_))]))
(define %next-to
(%rel (A B C)
[(A B C)
(%or (%left-of A B C)
(%left-of B A C))]))
(define %left-of
(%rel (A B C)
[(A B C) (%append (_) (cons A (cons B (_))) C)]))
(define %zebra
(%rel (Owns HS)
[(Owns HS)
(%is HS (list (list (_) 'norwegian (_) (_) (_))
(_)
(list (_) (_) (_) 'milk (_))
(_) (_)))
(%select (list (list 'red 'englishman (_) (_) (_))
(list (_) 'swede 'dog (_) (_))
(list (_) 'dane (_) 'tea (_))
(list (_) 'german (_) (_) 'prince))
HS)
(%select (list (list (_) (_) 'birds (_) 'pallmall)
(list 'yellow (_) (_) (_) 'dunhill)
(list (_) (_) (_) 'beer 'bluemaster))
HS)
(%left-of (list 'green (_) (_) 'coffee (_))
(list 'white (_) (_) (_) (_))
HS)
(%next-to (list (_) (_) (_) (_) 'dunhill)
(list (_) (_) 'horse (_) (_))
HS)
(%next-to (list (_) (_) (_) (_) 'blend)
(list (_) (_) 'cats (_) (_))
HS)
(%next-to (list (_) (_) (_) (_) 'blend)
(list (_) (_) (_) 'water (_))
HS)
(%next-to (list (_) 'norwegian (_) (_) (_))
(list 'blue (_) (_) (_) (_))
HS)
(%member (list (_) Owns 'zebra (_) (_)) HS)]))
(%which (Who HS) (%zebra Who HS))
</lang>
Output:
<pre>
'((Who . german)
(HS
(yellow norwegian cats water dunhill)
(blue dane horse tea blend)
(red englishman birds milk pallmall)
(green german zebra coffee prince)
(white swede dog beer bluemaster)))
</pre>
=={{header|Tcl}}==
| |||