Re: [Haskell-cafe] Conditionals and case expressions in do blocks

26 Jan 2011


      Excerpts from Edward Amsden's message of Wed Jan 26 15:51:46 -0500 2011:
...
do
...
case ... of
Foo x -> do ...
                  ...
                  return foobar
Bar x -> do ...
                 ...
                 return foobar
There's not enough context here to say what is appropriate.
Is foobar defined in the outer or inner do-block?
...
if cond
  then throwError "BBQ!"
  else do
         ...
         ...
         return ...
Try:

    when cond $ throwError "BBQ!"
    ...
    ...
    return ...

Cheers,
Edward

Re: [Haskell-cafe] Conditionals and case expressions in do blocks

Edward Z. Yang