RE: Compiler error using IO

4 Jan 2002

      | When trying to right IO I continually run across this
| sort of compile error which I just don't understand.
| Any help would be very muich appreciated.
|
| Function:
|
|
| while :: IO Bool -> IO () -> IO ()
|
| while test action = do res <- test
|                         if res  then do action
|                                         while test action
|                                 else return ()

Haskell uses "layout" to reduce the need for parentheses.  For your code to
parse, "if" should align with "res" vertically, as in:

 ... = do res <- test
          if res ...

- Zhanyong

RE: Compiler error using IO

Zhanyong Wan