GHCi debugger status
daniil.elovkov at googlemail.com
Mon Nov 24 11:28:02 EST 2008
Peter Hercek wrote:
> Daniil Elovkov wrote:
>> A refinement of :tracelocal could be :tracedirect (or something) that
>> would save the history not anywhere within the given function but only
>> within parents, so to say. For example,
> This looks like what I thought of as searching for values in dynamic
> stack (explained in my response to Pepe Iborra in this thread).
Yes, first when I saw that your message I also thought "Hey, Peter has already suggested it!" :)
But now I see that we're talking about slightly different things. Consider
fun x y =
let f1 = ... (f2 x) ... -- f1 calls f2
f2 = exp_f2
Now, if we're at exp_f2 then 'dynamic stack' in your terminology includes (f2 x) since it's the caller and all f1 as well.
On the other hand, :tracedirect that I suggested would not include f1, as it's not a direct ancestor. And for the purpose of binding variables which are syntactically in scope, it is indeed not needed. :tracedirect would be sufficient.
Also, I think that :tracedirect can be easily implemented based only on simple syntactic inclusion relation.
> I just did not ask for it with a new ticket since:
> * I think it is already requested by some other ticket
> * if you compile with -Wall then :tracelocal should have the same
> information and only rarely name collision happens so automatic
> tracelocal trace search should return what you are looking for
> too and when needed it reruns more ... that is if the function
> is short enough to fit in the tracelocal history queue
> The ticket actually has two almost independent parts:
> * Adding tracelocal trace.
> * Adding the automatic search for symbols in the trace and
> the trace in the search could be also some other kind of
> trace like (e.g. dynamic stack). This would not be that
> useful though since the names at higher levels in stack
> are typically different. So to make it good it would
> require matching formal arguments to expressions on
> higher level and evaluating them, not that easy to do
> as simple tracelocal search which is just based on stupid
> string comparison.
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