From e3064650725db65f7526efacb54db51b0608f0ea Mon Sep 17 00:00:00 2001 From: Ian Lynagh Date: Sat, 12 May 2007 16:02:53 +0000 Subject: [PATCH] Give an example of how intersection takes elements from the first set --- Data/Set.hs | 11 ++++++++++- 1 file changed, 10 insertions(+), 1 deletion(-) diff --git a/Data/Set.hs b/Data/Set.hs index 9ec9e4c..04d0100 100644 --- a/Data/Set.hs +++ b/Data/Set.hs @@ -340,7 +340,16 @@ hedgeDiff cmplo cmphi t (Bin _ x l r) Intersection --------------------------------------------------------------------} -- | /O(n+m)/. The intersection of two sets. --- Elements of the result come from the first set. +-- Elements of the result come from the first set, so for example +-- +-- > import qualified Data.Set as S +-- > data AB = A | B deriving Show +-- > instance Ord AB where compare _ _ = EQ +-- > instance Eq AB where _ == _ = True +-- > main = print (S.singleton A `S.intersection` S.singleton B, +-- > S.singleton B `S.intersection` S.singleton A) +-- +-- prints @(fromList [A],fromList [B])@. intersection :: Ord a => Set a -> Set a -> Set a intersection Tip t = Tip intersection t Tip = Tip -- 1.7.10.4