Re: ADA Popularity Discussion Request

[Georg Bauhaus <sb463ba@l1-hrz.uni-duisburg.de>]

Dmitry A. Kazakov <mailbox@dmitry-kazakov.de> wrote:
 
:> (No matter in what language.) If all of them are
:> isolated in some module(s), where's the problem.
: 
: The problem is a geometric explosion of interfaces in cases like:
: 
: procedure Connect
: (DB : in out Data_Base; Server, Name, Password : String);

This is very much a procedure doing I/O. You cannot expect this to
work at an abstract level without hiding the outside world, can
you? And on the other hand, you have to serve the outside world
what it is expecting. If you use String values for the network
database connection credentials, what will be the interpretation
of of a Character value with 'pos > 127?  UTF-8? ISO-8859-1? Are
you connecting to DB2 on a mainframe?

To what extent is switching back and forth between Standard.String
and (Un)Bounded strings a problem? Where does it happen? Locally?
At I/O boundaries? If you store strings in one internal representation
in your program how many parameter profile variants will there be?

Would you also want a polymorhpic number type with automagic
conversion?


: For the user point of view, what is the difference between String and
: Unbounded_String to require explicit conversions between them? Isn't it an
: implementation detail?

The difference is the same as the difference between an array
of fixed size and a list. I guess that humans are more accustomed
to character lists than to something_else lists. Have you recently
read any complaints about fixed size arrays of something_else in
Ada?

:> Is it an
:> aesthetical problem to have to use Ada's verbosity with strings?
: 
: With strings it becomes compelling. The problem is fundamental, Ada's
: support of interface implementation is very rudimental. You cannot define
: the interface of abstract characters and then the interface of an abstract
: array of abstract characters.

Where would these abstract interfaces be useful?
Do you want to code convenient string conversion automagic to overcome
notions of what an array of characters is, in Ada? :-)

: And what will we do when Wide_Wide_String come?

Use it. When string memory and 32 bit instructions instead of
8 bit instructions is no concern, use it everywhere. :-)


-- Georg