From e41a0589d56703e371e10b7ede910a42ca4b2776 Mon Sep 17 00:00:00 2001
From: Rob Rix <rob.rix@github.com>
Date: Thu, 4 Aug 2016 11:12:52 -0400
Subject: [PATCH] Define recur by closing over the higher-order functions.

---
 src/Interpreter.hs | 10 +++++-----
 1 file changed, 5 insertions(+), 5 deletions(-)

diff --git a/src/Interpreter.hs b/src/Interpreter.hs
index af5179c0d..67baa7dfd 100644
--- a/src/Interpreter.hs
+++ b/src/Interpreter.hs
@@ -30,11 +30,11 @@ diffTerms :: (Eq leaf, Hashable leaf, Eq (Record fields), HasField fields Catego
 diffTerms construct comparable cost a b = fromMaybe (replacing a b) $ diffComparableTerms construct comparable cost a b
 
 diffComparableTerms :: (Eq leaf, Hashable leaf, Eq (Record fields), HasField fields Category) => DiffConstructor leaf (Record fields) -> Comparable leaf (Record fields) -> SES.Cost (Diff leaf (Record fields)) -> Term leaf (Record fields) -> Term leaf (Record fields) -> Maybe (Diff leaf (Record fields))
-diffComparableTerms construct comparable cost a b
-  | (category <$> a) == (category <$> b) = hylo construct runCofree <$> zipTerms a b
-  | comparable a b = runAlgorithm construct recur cost getLabel (Just <$> algorithmWithTerms construct a b)
-  | otherwise = Nothing
-  where recur a b = diffComparableTerms construct comparable cost a b
+diffComparableTerms construct comparable cost = recur
+  where recur a b
+          | (category <$> a) == (category <$> b) = hylo construct runCofree <$> zipTerms a b
+          | comparable a b = runAlgorithm construct recur cost getLabel (Just <$> algorithmWithTerms construct a b)
+          | otherwise = Nothing
         getLabel (h :< t) = (category h, case t of
           Leaf s -> Just s
           _ -> Nothing)