Re: Question for the folks who designed Ada95

[Samuel Mize <smize@imagin.net>]

Robert Dewar <robert_dewar@my-dejanews.com> wrote:
>Here is
> the full quote from the AARM if people do not have it
> at hand:
...
> This seems quite straightforward and convincing!

Well, not to me, but only because I don't understand it.
I copied the AARM quote below.

Can someone explain to me why, for instance, 'Min isn't considered a
predefined operation?  It's predefined, it operates on objects of the
given type.  But it wasn't made an operator, so it apparently wasn't
considered a predefined operation.

I'm not arguing against the passage, I'd just like some help
understanding it.

Best,
Sam

> 
> <<AARM B.2 (9-a)>>
> 
> 9.a   Reason:  We considered making shifting and rotating
> be primitive operations of all modular types.  However, it
> is a design principle of Ada that all predefined operations
> should be operators (not functions named by identifiers).
> (Note that an early version of Ada had "abs" as an
> identifier, but it was changed to a reserved word operator
> before standardization of Ada 83.)  This is important
> because the implicit declarations would hide
> non-overloadable declarations with the same name,
> whereas operators are always overloadable.
> 
> Therefore, we would have had to make shift and rotate into
> reserved words, which would have been upward incompatible,
> or else invent new operator symbols, which seemed like too
> much mechanism.
> 
> <<end of quote>>

-- 
Samuel Mize -- smize@imagin.net (home email) -- Team Ada
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