I can think of a few properties that folds can honor: 1. Promises to call f on all data (does not have any guarantees on order) 2. Promises to call f on all data in order (like a left fold) 3. Promises to call f "associatively" (perhaps can be formalized as an in order break down of the data into tree structures) I'm assuming at least #1 has a well known name (something completeness?) On Fri, Oct 23, 2015 at 11:49 AM, Tom Ellis < tom-lists-haskell-cafe-2013@jaguarpaw.co.uk> wrote:
On Fri, Oct 23, 2015 at 11:45:13AM -0400, Charles Durham wrote:
Let's say you have a function "thisFold :: (a -> a -> a) -> [a] -> a"
and it says that the function 'f' passed in must be associative.
Then it goes on to use f in "thisFold f [0,1,2]" like "f (1 (f 0 2))". Obviously f is still associative, but 'thisFold' did not call f 'associatively' on the data. My question is if there is a name for what property this broke by not calling f 'associatively'.
Does that make sense?
I don't think it makes sense. You're asking whether there's a *name* for the property it broke, but is there even a property it broke at all? If so, can you write the property down (without naming it)?
Tom _______________________________________________ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://mail.haskell.org/cgi-bin/mailman/listinfo/haskell-cafe