On Thu, Aug 09, 2007 at 02:29:50PM -0700, Chad Scherrer wrote:
Is there process for submitting functions for consideration for inclusion into future versions of the standard libraries? For example, I'd like to see this in Data.List:
extract :: [Int] -> [a] -> [a] extract = f 0 where f _ _ [] = [] f _ [] _ = [] f k nss@(n:ns) (x:xs) = if n == k then x:f (k+1) ns xs else f (k+1) nss xs
This behaves roughly as extract ns xs == map (xs !!) ns
except that it's a lot more efficient, and it still works if ns or xs (but not both) are infinite. Oh, and "ns" are required to be ordered and non-negative.
I'm guessing there are a lot of similarly simple handy functions, and I'm wondering if there's anything in place to avoid (1) reinventing the wheel, and (2) name clashes. Someone else may have written "extract" as well, meaning one of us wasted our time. And chances are, if they did, it has a different name, leading to forced qualified imports.
Finally, even if no one else is using it, it would be good to settle on reasonable names for things more easily. Is there a better name for this function? Is there a reason not to call it "extract"?
http://www.haskell.org/haskellwiki/Library_submissions Stefan