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-- Using 'id' as a control function, 'traverse id' performs a preorder traversal of
-- a tree: it returns a parent directory before its children. Write a control
-- function that makes 'traverse' perform a postorder traversal, in which it
-- returns children before their parent.
-- ghci> :l ControlledVisit.hs
-- [1 of 1] Compiling ControlledVisit ( ControlledVisit.hs, interpreted )
-- Ok, one module loaded.
-- Output of the following commands is manually shortened and formatted for clarity
-- ghci> traverse' id "test-9_b_1"
-- [Info {infoPath = "test-9_b_1", ...},
-- Info {infoPath = "test-9_b_1/dirC", ...},
-- Info {infoPath = "test-9_b_1/dirC/F", ...},
-- Info {infoPath = "test-9_b_1/dirC/E", ...},
-- Info {infoPath = "test-9_b_1/A", ...},
-- Info {infoPath = "test-9_b_1/B", ...},
-- Info {infoPath = "test-9_b_1/dirD", ...},
-- Info {infoPath = "test-9_b_1/dirD/G", ...},
-- Info {infoPath = "test-9_b_1/dirD/H", ...}]
-- ghci> traverse' (\list -> (tail list) ++ [(head list)]) "test-9_b_1"
-- [Info {infoPath = "test-9_b_1/dirC/F", ...},
-- Info {infoPath = "test-9_b_1/dirC/E", ...},
-- Info {infoPath = "test-9_b_1/dirC", ...},
-- Info {infoPath = "test-9_b_1/A", ...},
-- Info {infoPath = "test-9_b_1/B", ...},
-- Info {infoPath = "test-9_b_1/dirD/G", ...},
-- Info {infoPath = "test-9_b_1/dirD/H", ...},
-- Info {infoPath = "test-9_b_1/dirD", ...},
-- Info {infoPath = "test-9_b_1", ...}]
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