Input Line Editing

[Bob Pendleton]

>From article <23839 at bu-cs.BU.EDU>, by bzs at bu-cs.BU.EDU (Barry Shein):

> What I don't like about just putting it into a shell is that it then
> conflicts with habits when using a simple program which just does
> reads, a human interface issue. I also like the idea that any
> programmer's program (even a neophyte's own) tends to work more or
> less as well as the shell on really visible things like input editing.

Which is why I wrote ile.


> I haven't looked at the Unix COMND routines from, I believe, Columbia,
> perhaps I (we) should.

Don't know anything abou them. Hoew about sending me a pointer?


> The other question is, if it's done as an intermediate process how
> does the process know when to step out of the way because a newly
> started job is doing its own style of input editing? (yes, I'm bracing
> myself for the answer...)

Ile uses a pty to control io to the subprocess. So it just does an
ioctl to check the mode at times when the mode could have changed.
This works ok for raw and cbreak mode, but because ile wants to echo
characters itself it doesn't work very well when a program (like su)
just clears echo on the pty. Using this technique means that ile can
do an ioctl call for each character it processes.

I'm starting to think that the "right" thing would be for the pty to
cause an exception every time an ioctl changes the ptys mode. The
exception can be handled through code controlled by a select(). It
would have to be an exception that could be ignored or else the change
will break to much of the world.

Everything else I've been able to think of can be handled by machs'
concept of an environment server (I think).

> 	-Barry Shein, Boston University

		Bob P.
-- 
Bob Pendleton @ Evans & Sutherland
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