Add two examples (doctests) for the factorial function.

[spline3.git] / src / Misc.hs

diff --git a/src/Misc.hs b/src/Misc.hs
index fd6dd392bdb3c6e1247d2271f1aeedfa766f43a7..48482b4f69a2cfe580b8b34a605beae82565168b 100644 (file)
--- a/src/Misc.hs
+++ b/src/Misc.hs
@@ -7,6 +7,15 @@ where
 -- | The standard factorial function. See
 --   <http://www.willamette.edu/~fruehr/haskell/evolution.html> for
 --   possible improvements.
+--
+--   Examples:
+--
+--   >>> factorial 0
+--   1
+--
+--   >>> factorial 4
+--   24
+--
 factorial :: Int -> Int
 factorial n
     | n <= 1 = 1
@@ -24,7 +33,7 @@ flatten xs = concat $ concat xs
 --   equal. Returns False otherwise.
 all_equal :: (Eq a) => [a] -> Bool
 all_equal xs =
-    and $ map (== first_element) other_elements
+    all (== first_element) other_elements
     where
       first_element  = head xs
       other_elements = tail xs