Perhaps x is evaluated earlier than you think, i.e. before the trace
(due to some strictness analysis?). But this is a just a guess.
I usually use trace outermost in my expression, not within a let. I
never had a problem with it:
fA :: SomeInput - SomeResult
fA a = trace (Entering fA) $ f a
-- or even:
fA a = trace (Entering fA) $
f a
HTH
Thomas
Am 14.05.2013 15:03, schrieb hanjoosten:
My project is split in two packages, A and B, where B uses A. All together,
there are about 100 haskell modules.
Currently, there seems to be a loop somewere, that only seems to occur when
working with rather large datastructures. I use trace (from Debug.Trace) to
see what exactly is going on.
As long as I trace functions from B, trace works as expected. However, at
some point I need to trace into functions supplied by package A.
In package A I have a function like this: (I have simplified the function)
fA :: SomeInput - SomeResult
fA a = let x = f a
in trace (Entering fA) x
(The function f is defined in package A)
In package B, I have a function like this:
fB :: SomeInput - SomeResult
fB a = let x = fA a
in trace ( Entering fB) x
At runtime, I get the message
Entering fB
and then nothing more. a lot of cpu is used, but no more output.
I have made some wrappers like the ones above. As long as they are in the
same package, trace works fine. However, when entering a function from the
other package, there is no more debug output.
This is very anoying. Anyone some suggestions? Is this a bug?
I use the haskell platform 12.4.0.0 on a windows 7 machine.
--
View this message in context:
http://haskell.1045720.n5.nabble.com/Trouble-with-Debug-Trace-when-using-a-library-tp5730157.html
Sent from the Haskell - Haskell-Cafe mailing list archive at Nabble.com.
___
Haskell-Cafe mailing list
Haskell-Cafe@haskell.org
http://www.haskell.org/mailman/listinfo/haskell-cafe
___
Haskell-Cafe mailing list
Haskell-Cafe@haskell.org
http://www.haskell.org/mailman/listinfo/haskell-cafe
