Re: [Haskell-beginners] The case expression

23 Jan 2009

      Erik de Castro Lopo wrote:
...
Hi all,
Ocaml's match .. with expression (very similar to Haskell's case)
allows multiple matches for a single result (naive example):
let f x =
  match x with
        | 0 -> "zero"
        | 1 | 3 | 5 | 7 -> "odd"
        | 2 | 4 | 6 | 8 -> "even"
        _ -> "bad number"
Is there a similar thing in Haskell? At the moment I have to do
something like :
f x =
  case x of
          0 -> "zero"
          1 -> "odd"
          3 -> "odd"
          5 -> "odd"
          7 -> "odd"
          2 -> "even"
          4 -> "even"
          6 -> "even"
          8 -> "even"
          _ -> "bad number"
Cheers,
Erik
Hi Erik,

you can use guards like this:

f x
  | x == 0 = "zero"
  | x `elem` [1,3,5,7] = "odd"
  | x `elem` [2,4,6,8] = "even"
  | otherwise = "bad number"

daniel.

Re: [Haskell-beginners] The case expression

Daniel Seidel