From: Michael Orlitzky <michael@orlitzky.com>
Date: Thu, 1 Sep 2011 16:58:37 +0000 (-0400)
Subject: Add the 'disjoint' function.
X-Git-Tag: 0.0.1~190
X-Git-Url: https://gitweb.michael.orlitzky.com/?a=commitdiff_plain;h=42e5b4cc8b2dbd76ba4567b73967de974831c666;p=spline3.git

Add the 'disjoint' function.
---

diff --git a/src/Misc.hs b/src/Misc.hs
index 9dcbac9..b9220cb 100644
--- a/src/Misc.hs
+++ b/src/Misc.hs
@@ -3,6 +3,8 @@
 module Misc
 where
 
+import Data.List (intersect)
+
 
 -- | The standard factorial function. See
 --   <http://www.willamette.edu/~fruehr/haskell/evolution.html> for
@@ -57,3 +59,19 @@ all_equal xs =
     where
       first_element  = head xs
       other_elements = tail xs
+
+
+-- | Returns 'True' if the lists xs and ys are disjoint, 'False'
+--   otherwise.
+--
+--   Examples:
+--
+--   >>> disjoint [1,2,3] [4,5,6]
+--   True
+--
+--   >>>  disjoint [1,2,3] [3,4,5]
+--   False
+--
+disjoint :: (Eq a) => [a] -> [a] -> Bool
+disjoint xs ys =
+    intersect xs ys == []