Re: Ada design bug or GNAT bug?

[vincent.diemunsch@gmail.com]

Le lundi 22 juin 2015 20:27:17 UTC+2, Shark8 a écrit :

> * Ada95's modular types combine the orthogonal idea of a cyclic numeric type and an unsigned type -- conceptually it could have been better to separate the two.

Could you tell us a bit more on that ? Why would it be better to separate Unsigned Integer and modular types ? I had the impression that a compiler could use a unsigned integer representation for such integer declaration :

type Unsigned is range 0 .. 2**32 -1;

Since converting to a Standard.Integer requires anyway to use an explicit
conversion in the Ada language because of strong typing, not mentionning run-time tests on range, I thought it would be easy for the compiler to insert conversion between signed and unsigned.

But it seems that Ada implementations prefer to use 

type Unsigned is mod 2**32;

But what is the problem with this ? Detection of overflow ?



> * The lack of a "abstract type" that could be used to unify (e.g.) [[Wide_[Wide_]]String into a single "generic"/abstract type; ditto on Character.

Same question : what would be your proposal ?