Re: ada vs. cpp

[lutz@iks-jena.de (Lutz Donnerhacke)]

* Steven Deller wrote:
>> * Dmitry Kazakov wrote:
>> >1. If you mean that Ada has no type to represent the whole set of all
>> >integers, yes it is true. [as well as it is for all other languages
>> >designed for finite discrete machines]
>>
>> man Haskell. (or any other lazy evaluation language with
>> unlimited arithmetics)
>
>Of course that is limited by the machine memory, so it is unlimited, but not
>infinite and thus doesn't cover all integers either.

That's not my point.

In Haskell you write down an algorithms assuming unlimited ressources.
Due to lazy evaluation in a concrete situation with defined input data
the program executes in limited space (and time).

>Numerous unlimited arithmetic packages have been defined in Ada for
>integers, for rational's and for floating point.  Any type derived from
>those packages have the unlimited aspect you are looking for.  And they are
>used "naturally",

Of course. But Ada does not allow to use them as real scalars. You can't use
them as array indices or slides or even subtypes. Haskell does not limit this.
You can even define and work with the infinite entity 'all natural numbers'.

>I also believe one could create a symbolic processing type, which just
>collected operators without evaluation, and doing symbolic simplification
>before assignments.

Every language discussed so far is computionally equivalent to Brainfuck.
A language with an oracle or random source convers much more.