Excerpts from sean's message of Fri Jan 21 04:09:23 -0500 2011:
Daniel, you have confused me. In my RWH book there is a test from the PCRE example of nullPtr == x, so I just did my code using a case instead, I am sure it's correct!?!?!? If I run my program with the Wiimote off, it prints FAIL and if I press the red sync. button it then prints out OK and the memory address of the allocated structure so it surely must be workng as I expected?
A more direct answer is that you need to use a guard in this case: case x of x | x == nullPtr -> ... Or maybe in this case, using a regular conditional would be better. You can pattern match against constructors (things that are capitalized); variable names (lower-cased) will just assign new variables. Cheers, Edward