Re: Printing Enum Variable Re: Linux World

[Hans Marqvardsen <hm@ddre.dk>]

dewar@gnat.com wrote:
> Note that for most purposes, it does not matter at all
> what the external relationships are (you put characters
> into your program, and they come out "right").

However, the programmer (and the maintainer of his program) must
remember that they may get strange results,

if they ever compare strings except for equality 

or if they ever use the otherwise nice 
classification functions of Ada.Characters.Handling,  
Is_Control, Is_Graphic, Is_Letter, Is_Lower, Is_Upper,

or conversion functions:
To_Lower, To_Upper, To_Basic.

In conclusion: 
this is really a poor mans way of dealing with the full
character set.

> If the wrong
> characters are coming out, talk to your OS vendor, not
> your compiler vendor

There are in fact these two approaches:

a) Make the OS do the right thing
b) Give your program a suitable interface to the OS at hand

OF COURSE, in theory option a is preferable, but in practice
this approach can be difficult.

In Windows NT one can use the OS-supplied procedures
SetConsoleCP and SetConsoleOutputCP to use the proper codepage.
However one still has to select a non-default font, Lucida console,
manually at execution. 

Under Windows 95, it just cant be done, IMHO.

Option b may look more messy, but it works better IMHO.

The desired interface, such as Console_Io, can be constructed from the
OS-supplied procedures  CharToOemA and OemToCharA. 
No need to select any non-default font.
Works for W95 and NT alike.

Hence in practice option b is preferable, maybe the only possible.