Uncommon Pattern Matching Operations

pattern1 - pattern2 # pattern1 so long as it's
                    # not pattern2
- pattern           # OK so long as pattern
                    # doesn't match
SucceedP ()         # force whole pattern to succeed
FailP ()            # force whole pattern to fail
UnorderedP (pattern, ...)
                    # match patterns in any order
All About Pattern Matching Sam Wilmott
Slide 23 of 37         example www.wilmott.ca