Robby Findler wrote:
I tried to follow the steps with collects/drscheme/private/rep.ss and
couldn't make it fail. Specifically, I hit return on the second line
(making the buffer modified) and then check syntax; I waited until it
was in "coloring" mode (according to the status line) and then hit
cmd-s (for save) and nothing bad happened. I only tried it about 4
times, tho, so maybe I just didn't try enough?
The problem occurs for me even if I click Save just once, although there
is a time delay between clicking and the error.
Or possibly because I'm using a mac there is something about the way
event handling works on the mac that makes me miss the bug (because
the save button does not go away until check syntax completes).
I'm on a mac too.
Looking at the code, I think this could happen if the buffer were
modified (triggering a callback that sets arrow-vectors to #f) while
check syntax were still coloring the buffer. Check syntax does do
things like lock the editor in order to ensure that those callbacks
don't happen.
So I guess the thing to do would be to figure out how it is getting
set, probably by inspecting the stack at the point where (set!
arrow-vectors #f) happens (line 404). If you dont' mind, could you add
this between lines 403 and 404 and send the output?
(printf "~s\n" (continuation-mark-set->context
(current-continuation-marks)))
I don't mind. I made this edit, but where does this output go? I tried
opening DrScheme from the terminal, but I don't see any output there and
so far as I can tell, there is no output in DrScheme.
... are you in a teaching language? That would actually make more
sense to me (but I'm still not getting the error to happen there
either).
Yes, I am using ISL/lambda (this was in the original msg). I just
confirmed -- the bug only occurs when I am in a student language.
David
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