Re: Is this expected behavior or not

[Georg Bauhaus <rm.dash-bauhaus@futureapps.de>]

On 17.04.13 11:57, Dmitry A. Kazakov wrote:

>> If the Ada type system cannot express
>> time and space, I'll still consider them
>> functional requirements.
>
> And this should justify conflation of a representation with the type
> semantics... surely.

Representation is functional, like it or not, and it is meaningful,
therefore it is semantically important.

Nothing is conflated here because semantics is assignment of meaning,
not just types-whatever. Provide a different hook for stating
functionally important representation and programmers might use it.
For example, for this: "Make X a Θ(1) data structure of equally shaped
objects of the same subtype, of a certain finite length, indexed by
certain discrete values, components well aligned."

For sure, type semantics, if that restriction should so easily mean a
thing in a real-world programming language, isn't semantics.  The
meaning of an Ada program, for example, is determined by the
implementation (RM 1.1.3). Period. That's also true in other
languages.

But I can be certain to get the Θ(1) thing mentioned above by making
the necessary declarations in Ada, because of the meaning it assigns
to "array".

String is a good example. String is an array, and nothing else.

The existence of RM A.4.({4,5}) is of no consequence. To hell with it.

The existence of RM 3.6 is essential, because of array semantics.

(And I don't care much about string literals because many are read
from external sources during start-up. YMMV.)

The only important type for text processing for me is the universal
type to be used for defining text character types, because ranges of
characters match notions relating to text just like ranges of whole
numbers match notions relating to mathematical integers.  There are
excellent libraries full of text processing operations. If they give
rise to universally good operators, excellent! If they need to involve
representation, then so be it. I live in and off dirt, not
mathematical purity, so long as the latter offers no way to denote
functional requirements such as representing objects.