Re: System.WCh_Cnv

[Marius Amado-Alves <marius@amado-alves.info>]

>> Actually the Unicode codepoint range is 0 .. 10FFFF and therefore
>> fits in 21 bits.
>
> ... the definition would allow expansion to 31-bits (but no
> further).

The definition of some particular *encoding* namely UCS-4. Not of the  
"character set" range. Character = codepoint. And this stops at  
10FFFF. And it will not be extended. IIRC both Organizations went on  
record on this. Silly maybe, but not per se. It has to do with  
variable length encodings. It facilitates search and verification.  
Now these encodings may be a bit silly, yes.

I have been sketching a highly simplified, short, clear, logical,  
understandable, usable, no nonsense, package for Unicode. I have not  
been making much progress for several reasons. If someone wants to  
join that would be great. The first lines of the spec follow.

-- Unico : no nonsense Unicode support for Ada
-- (C) 2006 Marius Amado Alves

with Ada.Containers.Vectors;
with Ada.Streams;

package Unico is

    type Character is range 0 .. 16#10FFFF#;
    for Character'Size use 24;

    procedure Write
      (Stream : access Ada.Streams.Root_Stream_Type'Class;
       Item   : in Character);

    procedure Read
      (Stream : access Ada.Streams.Root_Stream_Type'Class;
       Item   : out Character);

    for Character'Write use Write;
    for Character'Read use Read;

    package Strings is new Ada.Containers.Vectors
      (Index_Type => Positive, Element_Type => Character);

    subtype String is Strings.Vector;

    type Fixed_String is array (Positive range <>) of Character;
    for Fixed_String'Component_Size use 24;
    pragma Pack (Fixed_String);