import "Prelude" dists l = sum [sqrt (dx*dx + dy*dy) | i <- [0..length l-2] , (x1,y1) = l!i , (x2,y2) = l!(i+1) , dx = x1-x2 , dy = y1-y2 ] main = dists [(0,0),(1,1),(2,0)] -- 2.8284271247461903