From 90d66dedc3a2d9b03dfd3dc3314d380e2adcf2ea Mon Sep 17 00:00:00 2001
From: Chris Martin
Date: Sun, 10 Apr 2016 18:55:45 +0200
Subject: [PATCH] Add doc to (<=<) comparing its type to (.)
This is another documentation addition similar to D1989, this time
comparing the type of the Kleisli composition operator (<=<) to that
of plain function composition (.).
Reviewers: hvr, austin, bgamari
Reviewed By: bgamari
Subscribers: thomie
Differential Revision: https://phabricator.haskell.org/D2100
---
libraries/base/Control/Monad.hs | 7 ++++++-
1 file changed, 6 insertions(+), 1 deletion(-)
diff --git a/libraries/base/Control/Monad.hs b/libraries/base/Control/Monad.hs
index 9d858bd332..a964581fef 100644
--- a/libraries/base/Control/Monad.hs
+++ b/libraries/base/Control/Monad.hs
@@ -104,7 +104,12 @@ infixr 1 <=<, >=>
(>=>) :: Monad m => (a -> m b) -> (b -> m c) -> (a -> m c)
f >=> g = \x -> f x >>= g
--- | Right-to-left Kleisli composition of monads. @('>=>')@, with the arguments flipped
+-- | Right-to-left Kleisli composition of monads. @('>=>')@, with the arguments flipped.
+--
+-- Note how this operator resembles function composition @('.')@:
+--
+-- > (.) :: (b -> c) -> (a -> b) -> a -> c
+-- > (<=<) :: Monad m => (b -> m c) -> (a -> m b) -> a -> m c
(<=<) :: Monad m => (b -> m c) -> (a -> m b) -> (a -> m c)
(<=<) = flip (>=>)
--
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