Clean up some hLint warnings.

[spline3.git] / src / Misc.hs

diff --git a/src/Misc.hs b/src/Misc.hs
index 6364e95e2c6f3b97794a609bbc7df6c40bd9b65a..6b5a84d20af8d79ea3eac277b5032eaf9123a8c5 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
@@ -16,5 +25,35 @@ factorial n
 
 -- | Takes a three-dimensional list, and flattens it into a
 --   one-dimensional one.
+--
+--  Examples:
+--
+--  >>> flatten [ [[1,2], [3,4]], [[5,6], [7,8]] ]
+--  [1,2,3,4,5,6,7,8]
+--
 flatten :: [[[a]]] -> [a]
 flatten xs = concat $ concat xs
+
+
+-- | Switch the x and z dimensions of a three-dimensional list.
+transpose_xz :: [[[a]]] -> [[[a]]]
+transpose_xz [] = []
+transpose_xz [[]] = [[]]
+transpose_xz [[[]]] = [[[]]]
+transpose_xz m =
+    [[[ m !! x !! y !! z | x <- [0..xsize]]
+                      | y <- [0..ysize]]
+                      | z <- [0..zsize]]
+    where
+      zsize = (length m) - 1
+      ysize = (length $ head m)- 1
+      xsize = (length $ head $ head m) - 1
+
+-- | Takes a list, and returns True if its elements are pairwise
+--   equal. Returns False otherwise.
+all_equal :: (Eq a) => [a] -> Bool
+all_equal xs =
+    all (== first_element) other_elements
+    where
+      first_element  = head xs
+      other_elements = tail xs