hierarchical debugging

[Todd Stock <todd%ptolemy.arc.nasa.gov@RELAY.CS.NET>]

After using Quintus Prolog for 4 years I got in the habit of tracing
a program in levels, that is I could skip along at the top level seeing
ONLY calls and "return values".  Then, when I found wierd behavior, I
could back up, call the function again but this time recursively tracing
one level deeper.  In this way you can significantly minimize the junk
you see traced and essentially go right to the problem.

So now I'm working on the Symbolics (and liking it BTW) but I can't seem
to pull off this simple debugging strategy even though I've seen it done
in simpler lisps.  I have seen trace including the :step option or what-
ever it's called but it's ridiculous to assume I know in advance what
to put a trace on.  What I'm doing now is to trace EVERYTHING in the
package I'm using.  (I mention this to evoke sympathy :-)  )

Come to think of it, I even implemented a simple and barely working 
version of this using eval-hooks in Xlisp!

Please help me if you can, I'm losing patience with the inefficiency
of all this...


-- 
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| Todd S. Stock                                    todd@ptolemy.arc.nasa.gov |
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