Re: Interpretation of extensions different from Unix/Linux?

["Randy Brukardt" <randy@rrsoftware.com>]

"Dmitry A. Kazakov" <mailbox@dmitry-kazakov.de> wrote in message 
news:cbxuxz06dr5r$.9zo0supfl50x.dlg@40tude.net...
> On Fri, 14 Aug 2009 18:54:40 -0500, Randy Brukardt wrote:
...
>> You mean, "Ada cannot provide this optimally". As far as the ARG is
>> concerned, a UTF-8 encoded string is a String. We looked at other options
>> and decided they weren't worth the effort.
>
> But UTF-8 encoded string is a Wide_Wide_String. The elements of a Unicode
> string are code points (Wide_Wide_Character). It is only the 
> representation
> which is a string of octets (not Character!). Who should care of
> representations in Ada?

If course you care of representations. A Wide_Wide_String takes 4 times as 
much space as a UTF-8 encoded string, which can be a severe performance 
drag. And if you *don't* care about representation, then just store 
everything as Wide_Wide_String and do not worry about the representation at 
all.

For Ada purposes, UTF-8 is a storage format, not an operation format. You 
manipulate a Wide_Wide_Character string, then convert to/from UTF-8 for 
storage only.

...
>> No, actually it is just wrong! There are many roots in Windows that don't
>> have the disk name syntax. "C:\" is surely a root, but so is
>> \\Gatekeeper\Weblogs\. You can't enumerate roots in Windows, the only
>> program that ought to try is Windows Explorer.
>
> Maybe, but these are not "true" roots of the file system.

What is a "true" root? There are only file names which form roots (that is, 
cannot be decomposed further and still give a file or directory). It doesn't 
matter where the storage is or what the technology is.

...
> If Ada.Directories is provided it must be specified as a useful package.
> Its implementation under Windows or Unix (of which file system is no less
> broken) is not a matter of concern. I see no problem with traps or even 
> Ada
> RTL starting processes and system services, if Ada.Directories has been
> used by the executable. If it comes with this price I buy it. What I do 
> not
> buy is writing OS-dependent code myself.

I agree, but the problem is that you are asking to write code that you ought 
not even be writing for Windows (and probably not for Unix as well). Ada 
shouldn't be in the business of encouraging you to write stupid code.

>> [And, yes, I agree with you that they shouldn't even have "=", but blame
>> Ichbiah for making these things Strings. It's 25 years to late to change
>> that definition.]
>
> No need to change, just overload it.

Can't overload "=" for type String, as it is in Standard and the predefined 
one is always visible. Any overloaded one would (almost) never be visible 
(use visibility has lower priority than things in Standard).

The problem here is that String really is not the right type, but since you 
can't have string literals for private types in Ada, you can't make it a 
private type. (And if you could have string literals, it still couldn't be 
used with the existing I/O packages, it would be way too incompatible.)

                                                     Randy.