[plt-scheme] Object Debugger release

From: Carl Eastlund (cce at ccs.neu.edu)
Date: Tue Dec 12 14:36:03 EST 2006

On 12/12/06, Geoffrey S. Knauth <geoff at knauth.org> wrote:
> Amen.  One comment, regarding the sequence trace:
> http://www.ccs.neu.edu/home/cce/object-debugger/complex-b.png
> On the left hand side, at Obj5 return-> Obj2:  visually I was
> expecting a return arrow pointing left (<-return), but the order Obj5
> -> Obj2 makes sense, and Obj2 <- Obj5 might be confusing when looking
> down columns 1 and 3 (column 2 being the arrows/messages).  Maybe the
> word return above the arrow could be slanted.

Indeed, the purpose of the left-hand sidebar is to provide quick
access to the action's source and target objects when the action arrow
has scrolled off the left and right of the screen.  Right now all it
does is tell you the numbers, but in the next version I will fix the
feature that lets you jump to those objects.  Because the arrows are
not always in the visible portion, I thought it was best to
standardize on "SOURCE --> TARGET".  But you're right, it could use
some visual cue when the action arrow goes the other way.

> The arrows on the right hand (wide) part of the sequence diagram are
> completely clear.  The sequence diagram is the clearest I've seen.  I
> have some fancy expensive Java tools that don't even come close.

Thanks, glad to hear it.

> Thinking about Java made me think about threads, which of course PLT
> Scheme has too.  I wonder what these diagrams would look like with
> threads.

That's something we haven't worked on specifically yet, so right now
the tracer would probably just show confusing results, but we hope to
improve that soon.

Carl Eastlund

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