I sometimes encounter quite bizarre behaviour from Hugs, both 1.3 and
1.4. Often what happens is this: I'm happily developing a program and
a session has been running for somewhere between 10 mins and an hour.
All of a sudden I get a really weird output, no "error", just really
weird output. I study my program intensely, become flustered over not
being able to work out what's going wrong and then finally one of two
things happen:
1) I give up, quit the session and come back to it later, only to find
that it is now giving the expected answer...
or
2) I remember how Hugs has done this to me in the past, immediately
quit the session, immediately re-start, re-load and hey presto,
everything's ok (talk about the typical "switch the computer off and
on again and everything will be fine"-fix to computer problems!).
(2) is usually triggered by extreme frustration and by chance that I
forget the "if I see a wrong result, my program's wrong not the
interpreter/compiler" attitude I've developed, or I sometimes am
finally greeted with an "INTERNAL GRAPH ERROR" remark after several
minutes of wrong answers and frustrated scrutinies of my program. I
was recently greeted with a new error on me: "INTERNAL ERROR:
depTypeExp" whilst loading (again, quit and re-start "fixed" it).
This kind of bug has never been repeatable in my experience and is
extremely frustrating (it only happens once every two or three days
though thankfully). Is there anything I can do to help debug this?
Cheers,
Graeme.
