Re: [q-lang-users] New stuff in cvs: multichar ops, views

[Rob H. <hub...@gm...>]

Hello Albert,

On 31/05/07, Albert Graef <Dr....@t-...> wrote:
> John Cowan wrote:
> > I'm happy with that -- I assume that "--" is distinct from "- -"
> > where the latter is unary minus?
>
> Yes, sure. The unparser now also makes sure that spaces are inserted
> between adjacent binary and unary symbols.
>
> But note that this was just an example, (--) is not in the standard
> library. So unless you define (--) yourself you can still write 5--3 and
> get the expected result, 8. :)

I'm very happy to see multi-character operators introduced. (Does Q
also allow Unicode operators?)

I presume that tokens will be delimited according to which set their
constituent characters belong to: 'alphanumeric' or 'other' (although
an 'alphanumeric' token must begin with an alphabetical character, of
course). Is white-space a special case, i.e. a third class of
character?

Which characters are in the 'other' set for operators - are any (such
as quote and parentheses) excluded?

Does this also mean that multi-other-character function names are also
supported? That is, can I now define a non-operator function called
'--'? (I suppose that includes the secondary question: would 'other'
characters count as lower case?)

It seems that now, introducing a new symbol will affect the way that
code is parsed. This is something I find a little worrying.

Would it be better to have, e.g. '--' always as an atomic token,
producing a normal form unless '--' is defined? That is, would is be
better to break backwards compatibility? Or would that be too painful?

Is the protection offered by the module system thought to be enough?

[Can of worms! Sorry.]

Thanks,
Rob.