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Re: FD 2.0 is quite a tool! --long post
On Fri, 16 Jun 2000 10:30:20 +0100, "Rob Myers" <robm@tdv.com> wrote:
> >From: Jason Trenouth <jason@harlequin.co.uk>
> >Subject: Re: FD 2.0 is quite a tool! --long post
> >
> > I'm also trying to encourage a convention where false-or types are made
> > explicit by combining the conventions for types and predicates as follows:
> >
> > define constant <thread-frame>? = false-or( <thread-frame> );
> > define variable *display-thread-frame* :: <thread-frame>? = #f;
>
> This is cool. Should that be <thread-frame?> ? The <> emphasize
> classness, which should probably have higher precedence than precendence.
> Also, people are used to typing the <> outside everything else, so this may
> lead to more mis-types. Just thinking out loud. :-)
Well, I considered that alternative when I dreamt up the convention, but I
prefer <thread-frame>? because I think of the type as modifier on
<thread-frame> (like false-or() itself), and so mangling the ? inside the <>
didn't feel right to me.
__Jason
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