[Haskell-cafe] if-then without -else?

[Tom Ellis]

On Mon, Jul 09, 2018 at 08:39:49PM +0200, Johannes Waldmann wrote:
> > Therefore (if False then a) would give an exception.
> 
> Yes. And the question is, why is possible to write
> this program using "case" but not with "if".

Because the error conditions around case were badly designed.  My
understanding is that a large majority of Haskell developers believe that it
should not be possible to omit a branch in a case statement.