[SGVLUG] Vim on Dumb Terminal Prob. (was Re: My Debian upgrade ...)

[David Lawyer]

On Thu, May 03, 2007 at 02:05:46PM -0700, John E. Kreznar wrote:
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> David Lawyer <dave at lafn.org> writes:
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> > I just installed something which is newer than Debian Etch.  It's
> > the Debian "testing" version which is unstable but newer.
> 
> and in a later mail

> > [vim] only has [a] bug on my 24-year-old dumb terminal but prior to
> > upgrading worked fine on the terminal.  So it's a software bug in
> > the dumb terminal interface that almost no one else will likely
> > experience.
[snip]

I inspected escape sequences and it turns out that the bug is an
illusion.  What's going on the that vim is emphasizing bracket pairs
(by reverse video) when the cursor is on one of the brackets.  It so
happens that my cursor is reverse video.  So if I'm moving the cursor
one char. at a time by the space-bar, etc. then when I move it to an
opening bracket, like (, [, or {, the cursor seems to jump to the
closing bracket.  But that's just an illusion because what really
happens is that the opening bracket is emphasized by reverse video as
the cursor moves onto it, but since the cursor is reverse video, it
reverses the reverse video of the emphasis resulting in normal video.
This event is too fast to see and it looks just like the cursor
disappeared and jumped the the closing bracket which also gets
emphasized by the reverse video.  So the opening bracket both has a
reverse-video cursor over it and also has reverse video emphasis.
Both of these combined result in normal video so both the cursor and
the emphasis are invisible.

But I turned in a bug report anyway.  Escape sequences to the terminal
can select both the type of cursor and type of emphasis so that they
don't cancel out each other like they did in my case.

			David Lawyer