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From: bevan@cs.man.ac.uk (Stephen J Bevan)
Newsgroups: comp.lang.scheme
Subject: Logical operations on integers.
Message-ID: <BEVAN.91Apr5092119@panda.cs.man.ac.uk>
Date: 5 Apr 91 08:21:19 GMT
Sender: news@cs.man.ac.uk
Distribution: comp
Organization: Department of Computer Science, University of Manchester
Lines: 31

To provide a reasonably portable implementation of Icon like character
sets in Scheme I need the equivalent of CommonLisp's logical
operations on integers i.e. logand, logior ...  etc.

As these sort of operations are not in Scheme, I'm going to add them
to the Scheme I use.  In an effort to maintain some sort of
compatibility, I'd like to use the same name as any existing
extensions.  So, if these sorts of operations are in some Scheme
implementations (e.g. T, CScheme, Chez, Mac ... etc.), what are they
called?

Regarding portability :-

Shouldn't logical operations of this sort be included in a standard?
Not necessarily in the base language, but perhaps something along the
lines of ``if logical operations are provided they should be called X,
Y, Z and they should do P, Q, R when applied to integers''

Note I don't advocate adding everything to the language (I know where
Common Lisp is if I want it), but rather adding features that are
difficult to or cannot be implemented using other Scheme primitives.
For example I would like Icon like Csets.  However, I don't advocate
adding them to the language, as I can implement them as vectors of
integers using logical operations on the integers.

I would guess there are other things that could benefit from this sort
of definition (not that I can think of any at the moment)

thanks

Stephen J. Bevan			bevan@cs.man.ac.uk