[plt-scheme] mred in console mode on Debian

From: Robby Findler (robby at cs.uchicago.edu)
Date: Sun Apr 13 10:16:53 EDT 2008

Your REPL thread and the thread that handles GUI events are one and
the same thread. This means you're blocking the handling of events by
the "read" that is sitting waiting for input in the REPL.

You should be able to see this by evaluating (yield) a few times in
the REPL to handle the queue'd up events.

Probably the simplest thing is for you to do to fix this is to create
a new thread to handle the REPL and have the evaluator of that REPL
queue callbacks to that one thread to do the actual evaluation, so you
don't accidentally introduce concurrency into your program. You might
find this ICFP paper helpful:


(Continue on this road for too long and you'll end up with DrScheme :).


On Sun, Apr 13, 2008 at 9:12 AM, dragal V2.0.3 <dragal23 at gmail.com> wrote:
> Hi,
>  I want to run mred under emacs. Running mred with the -z option seemed
>  to fix this until I tried the test case below
>  (define frame (instantiate frame% ("Example")))
>  (define msg (instantiate message% ("Hello World!" frame)))
>  (send frame show #t)
>  Which displayed a window of the right size, but no text within it. The
>  above does not work correctly running mred -z directly on the console,
>  however it does work when mred is run with no arguments.
>  What is the cause of this and how do I fix it?
>  Dragal
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