Re: [Haskell-cafe] Why does Haskell have the if-then-else syntax?

On Wed, 26 Jul 2006, Fritz Ruehr wrote:

On Jul 26, 2006, at 6:44 PM, Sebastian Sylvan wrote:

...

For example ...

if :: Bool -> a -> a -> a if True t _ = t if False _ e = e

-- example usage myAbs x = if (x < 0) (negate x) x

I suppose there might also be a case for flipping the arguments about like this:

if :: a -> a -> Bool -> a if t _ True = t if _ e False = e

This way it would follow foldr more closely, in recognition that the conditional is essentially the fold/cata/eliminator/... for booleans.

I found the argument order of the first if (Bool -> a -> a -> a) already useful for a 'case' with computed conditions: select = foldr (uncurry if_) http://www.haskell.org/hawiki/Case