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 <lenn...@augustsson.net > 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 <bugf...@gmail.com> > wrote: > > 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 <j...@n-brain.net> > wrote: > >> > >> 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. > > > > _______________________________________________ > > Haskell-Cafe mailing list > > Haskell-Cafe@haskell.org > > http://www.haskell.org/mailman/listinfo/haskell-cafe > > > > >
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