String handling and character encodings

["Björn Persson" <spam-away@nowhere.nil>]

Fionn mac Cuimhaill wrote:

> 5. Various extensions need to be done to character string handling.
> Gwindows tries to hide the difference between  character
> representation among the various versions of Windows by defining a
> GString to be composed of either ordinary or wide characters as
> needed, and likewise tries to hide the differences between various
> Windows API procedures and functions that use string arguments. This
> hiding philosophy in not completely implemented and  I still need to
> use a variety of Ada system packages that have both ordinary and
> wide-character versions. (Typically the wide versions, as I do all of
> my development on Windows 2K and XP)

If you're planning big extensions to the string handling, you may want 
to have a look at how I have tried to solve the character encoding 
problem in my EAstrings library, which is part of AdaCL. EAstrings keeps 
track of how each string is encoded and transcodes automatically when 
necessary. (The strings are "encoding-aware".) EAstrings doesn't just 
hide the difference between String and Wide_String. It handles all the 
encodings that the operating system knows about.

You can see the code in its current state at 
http://cvs.sourceforge.net/viewcvs.py/adacl/adacl/Include/ (the 
adacl-eastrings* files). It works on Gnu-based systems (and maybe some 
other unixoids if they have the Iconv functions). A Windows port is on 
the to-do list. (Speaking of which, I could use some help from a Windows 
programmer.)

-- 
Björn Persson                              PGP key A88682FD
                    omb jor ers @sv ge.
                    r o.b n.p son eri nu