Re: Emulation of Alt+Numpad+Digits behavior

Tim Roberts wrote:

> Jörg Henne wrote:
>
>>
>> That sounds really interesting. I've just read a few things about X 
>> and input methods. What irritates me about this solution is that it 
>> seems like it would need special support for each and every 
>> application. However, I'm looking for a solution which works with 
>> every or most of the existing applications.
>
>
>
> Is this goal even achievable?  The Alt-NumPad thing works in MS-DOS 
> and Windows because it's implemented in the BIOS, and because the 
> keyboard character sets mappings are universal and strictly 
> controlled.  Alt-0227 maps to "ã" because that's the way it is in the 
> standard code page.
>
> X, on the other hand, is not supposed to be defining policy.  Let's 
> assume your solution was implemented.  What would you expect to happen 
> when you do Alt-227?  What symbol would it be, and in what character 
> set?  Is it the same with a German keyboard layout?

I do think that this goal is achievable, because the Alt-Numpad 
functionality is so limited: all it does is to generate the same symbols 
without regard to any codepage, keyboard mapping etc. And that's what 
makes it useful im some cases (see below). And exactly because the 
functionality is not supposed to be flexible at all, I think that it 
doesn't necessarily conflict with the X paradigm.

Yes, with the german (or any other) keyboard  Alt-0227 generates an "ã". 
But beware: Alt-227 (without the leading 0) is different. This is 
because MS added the four-digit mappings in Windows in order to maintain 
compatibility with the three-digit ones from DOS.

> Can we say unconditionally that no X application currently uses 
> Alt-Numpad combinations?
>
> Or maybe I'm just scaring up issues where none exist.

I don't think that one can safely assume that no application ever uses 
Alt-Numpad combinations. However, if those applications exist, they are 
probably rather rare. So why do I want the Alt-Numpad feature anyway, 
you may ask. The reason is simple: some specialized devices like 
keyboards with integrated readers for Smartcards or keyboard-wedge style 
barcode readers transmit their data via this mechanism. And their reason 
to use it, is that it offers a channel which is guaranteed to be 
transparent. i.e. unencumbered by keyboard mappings etc.

Joerg Henne