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From: "Dmitry A. Kazakov" <mailbox@dmitry-kazakov.de>
Newsgroups: comp.lang.ada
Subject: Re: What would you like in Ada202X?
Date: Sun, 1 Jul 2012 10:25:07 +0200
Organization: cbb software GmbH
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Date: 2012-07-01T10:25:07+02:00
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On Sat, 30 Jun 2012 21:06:15 +0000 (UTC), Brian Drummond wrote:

> On Sat, 30 Jun 2012 20:43:17 +0200, Dmitry A. Kazakov wrote:
> 
>> On Sat, 30 Jun 2012 17:00:46 +0000 (UTC), Brian Drummond wrote:
>> 
>>> On Sat, 30 Jun 2012 14:34:10 +0200, Dmitry A. Kazakov wrote:
>> 
>>>> Code review and maintainability problems. The set of symbols cannot be
>>>> infinite.
>>> 
>>> Practical considerations surely restrict the length of additional
>>> operators, but I'm not sure that restriction belongs in the syntax.
>> 
>> I didn't meant length. I think that the number of operators should be
>> small to be memorizable. All symbols should be predefined, e.g. from the
>> Unicode page.
> 
> A symbol is not necessarily a single character;  "<="  already isn't.

This is an ASCII artefact. With Unicode adopted, there is no need in such
tricks. BTW, less-that-or-equal is one character: U+2264.

> And 
> restricting the sequence length necessarily restricts the number of 
> possible identifiers, so I'm not clear what you are suggesting.

Since we allowed Unicode anyway, we could allow all Unicode mathematical
operators for use as unary and binary operators. I don't see Unicode making
any distinction between unary and binary. If it does Ada should follow
that.

Unicode specifies some symbols as relations, some as operators. According
to that we can assign binary operator priorities (relational level vs.
binary adding level). When priorities are same, association of different
operators is illegal. Unary operators are highest level, right-to-left,
illegal to associate with any binary operators.

That is. No user-defined sequences.

-- 
Regards,
Dmitry A. Kazakov
http://www.dmitry-kazakov.de