From f0f966ee96e24226c5a68bf1ad3c87bb1bd6c8ee Mon Sep 17 00:00:00 2001 From: simonmar Date: Mon, 14 Mar 2005 15:52:03 +0000 Subject: [PATCH] [project @ 2005-03-14 15:52:03 by simonmar] doc comparing --- Data/Ord.hs | 7 +++++++ 1 file changed, 7 insertions(+) diff --git a/Data/Ord.hs b/Data/Ord.hs index 2be636c..b2f00f9 100644 --- a/Data/Ord.hs +++ b/Data/Ord.hs @@ -23,5 +23,12 @@ module Data.Ord ( import GHC.Base #endif +-- | +-- > comparing p x y = compare (p x) (p y) +-- +-- Useful combinator for use in conjunction with the @xxxBy@ family +-- of functions from "Data.List", for example: +-- +-- > ... sortBy (comparing fst) ... comparing :: (Ord a) => (b -> a) -> b -> b -> Ordering comparing p x y = compare (p x) (p y) -- 1.7.10.4