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

[Peter Schachte]

Hi Mireille,

On Thu, 4 Jun 1998, Mireille Ducasse wrote:

> >> One other command that would be useful (if it's implementable) would
> >> be to replace the goal at the current port with one the user types in.
> 
> I do not like thi too much as in the end the program that you are
> tracing is not at all the program source that you have in the file.

This seems to be the universal response.  I don't understand why.

I know when I'm debugging C code I sometimes modify variable values and
continue when I discover that the code didn't do the right thing, it's a
trivial fix, it took me a long time to get to this point, and I know or
suspect this isn't the bug I was looking for.  It's just a time saver, as it
lets you find multiple bugs in a single debugging session.

As I recall, the InterLisp debugger I used to use (15 years ago!) allowed
you to substitute a value to return from a suspended call.  I found it very
useful.  That debugger would suspend calls to non-existent functions, and I
often found it handy to run code that wasn't fully written, and "manually"
supply return values for unwritten functions.

If the Mercury group doesn't want to implement this sort of feature because
it's difficult, I understand that.  But I don't understand why anyone would
want not to have such a facility.


-Peter Schachte               | ....I have not failed. I've just found
mailto:pets at cs.mu.OZ.AU       | 10,000 ways that won't work.
http://www.cs.mu.oz.au/~pets/ |     -- Thomas Edison 
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