OT What does RET (Enter) do and how does it do it ??
Marko Vojinovic
vvmarko at panet.co.yu
Sun Aug 26 11:11:00 UTC 2007
On Saturday 25 August 2007 22:39, Aaron Konstam wrote:
> On Sat, 2007-08-25 at 17:24 -0500, Mikkel L. Ellertson wrote:
> > It is on an even lower level that that - when you hit a g, a g may
> > or may not be printed, depending on what is being done with the
> > input. (For example, if I am playing a movie with mplayer, f toggles
> > full screen mode, but is never printed.) Now, there are some
> > libraries that make thing easy for the programmer. The reason that
> > the editing keys work the same in so many programs is that they are
> > using the readline library routines. (man readline)
> >
> > You also have all the terminal control characters that can come into
> > play, depending on the interface and settings. (man stty)
>
> Ok, I went too far. Whatever program contols processing the keyboard
> input uses anything typed in the way it wants to use it. The point is
> that lf is not unique in that regard.
Just to emphasize that point some more --- *no* key is unique in that regard.
Not even shift, control, alt, even "win" keys, multimedia keys, etc...
This is the democracy principle of the keyboard: All keys are created
equal. :-)
How is the sequence of keystrokes interpreted by the software, and by which
software, is entirely different question. It is quite easy to create an app
where pressing left shift displays AA on the screen, while releasing it
displays BB. Of course, the right shift does the same, only it writes CC and
DD instead. All that, having 7+backspace+scroll lock combination to type
"Hello world!", and open a new terminal...
Once your app starts reading the keyboard stream directly, there is no limit
to what you can do, except by the hardware --- some keyboards can detect four
simultaneous keypresses, some five or more, some just three or even two
(although the latter are very rare). While that is the real difference in
keyboard quality, people mostly buy keyboards based on look&feel, not even
knowing that there may be some other parameters to consider... ;-)
Best, :-)
Marko
Marko Vojinovic
Institute of Physics
University of Belgrade
======================
e-mail: vmarko at phy.bg.ac.yu
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