[m-dev.] proposed command set for the internal trace based debugger

[Zoltan Somogyi]

Fergus Henderson wrote:
> Our execution mechanism optimizes away the REDO port.
> Instead, execution jumps directly to the place where execution will
> resume (i.e. a DISJ port).  

Peter Schachte wrote:
> That sounds like what you should show, then.
> Let me put it this way:  I don't want to step through a
> hundred redo-fail pairs.  Arriving immediately at the first REDO port that
> has a chance of succeeding is fine with me.  That's what the Quintus
> debugger does, too. 

That is exactly what you get with our scheme without the pessimization,
except it is called a DISJ port, not a REDO port, and you also get an event
at the DISJ port when you enter the first disjunct of a disjunction.

Peter Schachte wrote:
> But how is this different from > a REDO port anyway?

It shows you where forward execution resumes, not what you had to backtrack
across to get there. I.e. the difference is the hundred redo/fail pairs
you didn't want.

Zoltan.