On Fri, Mar 27, 2009 at 7:03 PM, Henning Thielemann < lemming@henning-thielemann.de> wrote:
On Thu, 26 Mar 2009, wren ng thornton wrote:
Thomas Hartman wrote:
Luke, does your explanation to Guenther have anything to do with coinduction? -- the property that a producer gives a little bit of output at each step of recursion, which a consumer can than crunch in a lazy way?
It has more to do with "tying the knot" (using laziness to define values in terms of themselves), though there are similarities. Take the function:
infZipWith f ~(x:xs) ~(y:ys) = f x y : infZipWith f xs ys
What about using a custom list type, that has only one constructor like (:), that is, a type for infinite lists?
Yes, that would be more correct. However, the lazy pattern match would still be necessary, because single-constructor types are lifted. And as long as you're doing that, you might as well go all the way to an infinite binary trie. Luke