Duncan Coutts
[..] I have a sneaking suspicion [exceptions] actually *is* `unsafe'. Or, at least, incapable of being given a compositional, continuous semantics.
Basically if we can only catch exceptions in IO then it doesn't matter, it's just a little extra non-determinism and IO has plenty of that already.
Couldn't you just substitute "catch exceptions" with "unsafePerformIO" here, and make the same argument? Similarly, can't you emulate unsafePerformIO with concurrency? Further, couldn't you, from IO, FFI into a function that examines the source code of some pure function, thus being able to differentiate funcitions that are normally "indistinguishable"? I've tried to follow this discussion, but I don't quite understand what's so bad about unsafeInterleaveIO - or rather, what's so uniquely bad about it. It seems the same issues can be found in every corner of IO. -k -- If I haven't seen further, it is by standing in the footprints of giants