On Sun, Jan 08, 2012 at 12:11:29AM +0800, Zhi-Qiang Lei wrote:
scan :: [Point a] -> [Point a]
scan p1 : p2 : p3 : xs
Patterns with constructors and multiple components must be surrounded
by parentheses. So this should be
scan (p1 : p2 : p3 : xs)
-Brent
