Re: [Haskell-beginners] Early return in IO monad

31 Aug 2013

      On Sat, Aug 31, 2013 at 08:05:26PM +0200, Nathan Hüsken wrote:
...
Hey,
Is it somehow possible to return "early" in a do block of the IO monad?
The eqivalent do in C:
void doBlock() {
    if (some preCondition) {
      return;
    }
    ...
}
???
Nope.  But you can say

  do ...
     when (not (some condition)) $ do
       the
       rest
       of
       the
       stuff

You can even indent "the rest of the stuff" directly under the 'when'
if you like, though IMO that may be a bit confusing.

-Brent

Re: [Haskell-beginners] Early return in IO monad

Brent Yorgey