On Thu, 2009-01-01 at 02:16 +0100, Martijn van Steenbergen wrote: > Luke Palmer wrote: > > First, by simple definition, id _|_ = _|_. Now let's consider foo _|_. > > The Haskell semantics say that pattern matching on _|_ yields _|_, so > > foo _|_ = _|_. So they are equivalent on _|_ also. Thus foo and id are > > exactly the same function. > > Would it in general also be interesting to look at foo == id for input > (_|_:xs) and all other possible positions and combinations of positions > for bottom? I wonder how many cases you need to take into consideration > to have covered every possible situation.
That case is already covered by the (x:xs) case. The interesting, potentially "extra", case is an infinite list. _______________________________________________ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
