[Haskell-cafe] Use unsafePerformIO to catch Exception?  Jonathan
Cast jonathanccast at fastmail.fm Wed Mar 25 02:49:32 EDT 2009
On Tue, 2009-03-24 at 23:13 -0700, Donn Cave wrote: > Quoth
Duncan Coutts <duncan.coutts at worc.ox.ac.uk>: > > You must not
do this. It breaks the semantics of the language. > > > > Other
people have given practical reasons why you should not but a > >
theoretical reason is that you've defined a non-continuous
function. > > That is impossible in the normal semantics of pure
functional languages. > > So you're breaking a promise which we
rely on. > Could you elaborate a little, in what sense are we
(?) relying on it? > I actually can't find any responses that
make a case against it on a > really practical level - I mean,
it seems to be taken for granted that > it will work as
intended,  It shouldn't be.       loop = loop     blam = error
"blam"     notReallyTry = unsafePerformIO . try . evaluate  Now,
normally, we have, for all x, y,        x `seq` y `seq` x     =
y `seq` x  But we