Readline (was Re: state of ghc6 on sparc)

Malcolm Wallace
Fri, 20 Jun 2003 13:33:05 +0100

"Simon Marlow" <> writes:

> > [SimpleLineEditor]
> It seems to behave strangely here:  I can delete the prompt, and if I
> move the cursor to the left and delete some characters, the characters
> to the right of the cursor don't move.  Also, the backspace key doesn't
> work, although C-Backspace does work (backspace works fine with
> readline).  This is in an xterm; in a cygwin shell window different
> strange things happen.

There were a couple of bugs (now fixed) in the version I posted which
account for being able to delete the prompt, and for some strange
behaviour when retrieving history whilst in the middle of the line.

But I'm also perfectly well aware that a different terminal environment
might completely mess up some assumptions in the keystroke lexer.
For instance, in a gnome-terminal, ^H and backspace register as the
same single character, but in cbreak mode the former is echoed to
screen as two characters, whilst the latter is apparently echoed
as one.  Or least, that was the case yesterday - today they seem to
be the same!

Perhaps the best way to take care of such differences is by turning
off terminal echo, but sadly there is no portable Haskell'98 method
for that.