Re: What's wrong with C++?

[Hyman Rosen <hyrosen@mail.com>]

On 2/17/2011 2:55 PM, Ludovic Brenta wrote:
> Hyman Rosen<hyrosen@mail.com>  writes:
>> And what does it mean for something to be
>> "really an integer"?
>
> Simple: integers have arithmetic, enumeration values don't.

C and C++ enumerations don't have arithmetic.
They do convert automatically to integers, but
they don't automatically convert back.

>> Ada 'Pos and 'Val attributes certainly give the illusion that Ada
>> enumerators are integers too!
>
> If you mean to say that Ada provides features for unsafe programming,

Not at all, merely that it's easy within the language to
convert back and forth between enumerations and integers.
Nothing unsafe about it.

> Now try this and see your "illusion" shattered by reality:
> type E is (A, B, C);
> B : E := E'Val (E'Pos (A) + E'Pos (C)); -- Constraint_Error

What illusion? I certainly know that Ada checks and C doesn't!

Oh, and don't Ada implementers go insane because enumerations
are supposed to provide the illusion of being consecutive even
in the face of representation clauses which give them arbitrary
underlying values?

Also, I don't know if you did this intentionally or not, but
you redefine the name B as a variable when it is already an
enumeration literal. Do I recall correctly that this works
because enumeration literals are "really" functions returning
their value, and functions can be overloaded?