[Haskell-cafe] Re: Function to find a substring

R J writes:

What's an elegant definition of a Haskell function that takes two strings and returns "Nothing" in case the first string isn't a substring of the first, or "Just i", where i is the index number of the position within the first string where the second string begins?

f n h = listToMaybe [b | (a,b)<- tails h `zip` [1..], n `isPrefixOf` a] seems plausible, but how do you define elegant? -- Jón Fairbairn Jon.Fairbairn@cl.cam.ac.uk