Or a StableName? I guess StablePtr prevents the GC to move the Haskell
object, so for just doing ugly comparing StableName would be better?
On Mon, Apr 20, 2009 at 12:45 AM, Lennart Augustsson wrote: And when the need gets big enough you pull out StablePtr and use that. :) On Sun, Apr 19, 2009 at 10:43 PM, Peter Verswyvelen Sometimes I do miss the pragmatic C solution:
- two function pointers that are equal surely represent the same
functions
(although in C nothing is really sure ;)
- two function pointers that are different, might or might not represent
that same functions.
But this weak equality can sometimes be handy.
For example, suppose you have a predicate a -> Bool, and a list of these
predicates [a -> Bool], but you want to remove all functions that are
obviously equal in the C way from the list for optimization... Okay big
hack, and one could do this already with reallyUnsafePtrEquality# I
guess...
On Sat, Apr 18, 2009 at 6:02 PM, John A. De Goes Two functions are equal iff they have the same domain and range and the
same outputs for the same inputs. Simple to state, but extremely difficult to implement in a useful way, and impossible to implement in a perfect
way. If you had a compiler or algorithm capable of determining function
equality, you could use it to prove or disprove arbitrary theorems in
mathematics. _______________________________________________
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