Or, if you need several cases, you can use something like:

funcGuard n | n `elem` [2,5,9] = 5 | n `elem` [4,18] = 1 | otherwise = 7

or, if you want an expression:

caseGuard n = case undefined of _ | n `elem` [2,5,9] -> 5 | n `elem` [4,18] -> 1 | otherwise -> 7

mike Dean Herington writes:

Mark Carroll wrote:

...

I can write a function x :: Integer -> Integer that returns 5 if I give it 2, 5 or 9, or 7 otherwise. Say,

x 2 = 5 x 5 = 5 x 9 = 5 x _ = 7

Generally, this is a question about where multiple cases lead to the same thing, maybe even in the middle of a function. (Like C's "case 1: case 2: case 3: foo; break;".)

Does it get any better than this, though? I can't convince 'case' to do something like,

case n of 2,5,9 -> 5 otherwise -> 7

Am I missing some syntax somewhere? I'm lost in the grammar in the Haskell report.

-- Mark

I would write:

...

if elem n [2,5,9] then 5 else 7

Dean