Version française
Home     About     Download     Resources     Contact us    
Browse thread
[Caml-list] fixpoint
[ Home ] [ Index: by date | by threads ]
[ Search: ]

[ Message by date: previous | next ] [ Message in thread: previous | next ] [ Thread: previous | next ]
Date: -- (:)
From: John Max Skaller <skaller@o...>
Subject: Re: [Caml-list] fixpoint
John Max Skaller wrote:

Woops:

> which suggests the following reduction:
>
>    fix f . fun x . e ==> fix z . e [f x -> z]
>
> Well, the rule works in this case. Will it always work?
>
I meant:

    fix f. fun x . e ==> fun x. fix z . e [f x -> z] (* z not occuring 
in e *)

ie. the fix and fun binders swap around with the substitution.
I should also have noted that obviously this only works if it is
done at the right time, eg in

    fix g. (fun x (fun f ( f x) g) x)

the inner redex must be reduced first.

-- 
John Max Skaller, mailto:skaller@ozemail.com.au
snail:10/1 Toxteth Rd, Glebe, NSW 2037, Australia.
voice:61-2-9660-0850




-------------------
To unsubscribe, mail caml-list-request@inria.fr Archives: http://caml.inria.fr
Bug reports: http://caml.inria.fr/bin/caml-bugs FAQ: http://caml.inria.fr/FAQ/
Beginner's list: http://groups.yahoo.com/group/ocaml_beginners