-- <Pre>

import Observe


n = 10

x1 = foldr (+) 0 [1..n]
y1 = foldr (observe "Add" (+)) 0 (observe "input" [1..n])
z1 = printO y1

x2 = foldl (observe "f" (+)) 0 [1..n]

x3 = foldr (+) 0 (reverse [1..n])
y3 = foldr (+) 0 (take 4 (observe "revlist" (reverse (observe "input" [1..n]))))
z3 = printO y3

x4 = foldl (+) 0 (reverse [1..n])
y4 = foldl (+) 0 (take 4 (observe "revlist" (reverse (observe "input" [1..n]))))
z4 = printO y4

-- </Pre>