Haskell guards on lambda functions?

Question

Is it possible to have guards on lambda functions?

For example:

\k
    | k < 0     -> "negative"
    | k == 0    -> "zero"
    | otherwise -> "positive"

Answer 1

Nope. The nearest direct translation is something a bit like

\k -> case () of
       _ | k < 0     -> "negative"
         | k == 0    -> "zero"
         | otherwise -> "positive"

Answer 2

I like to keep lambdas short and sweet so as not to break the reader's visual flow. For a function whose definition is syntactically bulky enough to warrant guards, why not stick it in a where clause?

showSign k = mysign ++ " (" ++ show k ++ ")"
  where
  mysign
    | k < 0     = "negative"
    | k == 0    = "zero"
    | otherwise = "positive"