diff options
Diffstat (limited to 'libraries/base')
| -rw-r--r-- | libraries/base/Control/Monad.hs | 2 | ||||
| -rw-r--r-- | libraries/base/Data/OldList.hs | 28 | ||||
| -rw-r--r-- | libraries/base/GHC/List.hs | 4 |
3 files changed, 34 insertions, 0 deletions
diff --git a/libraries/base/Control/Monad.hs b/libraries/base/Control/Monad.hs index 75bc2b2db3..fbdb99e5f4 100644 --- a/libraries/base/Control/Monad.hs +++ b/libraries/base/Control/Monad.hs @@ -191,6 +191,8 @@ forever a = let a' = a *> a' in a' -- data structures or a state monad. mapAndUnzipM :: (Applicative m) => (a -> m (b,c)) -> [a] -> m ([b], [c]) {-# INLINE mapAndUnzipM #-} +-- Inline so that fusion with 'unzip' and 'traverse' has a chance to fire. +-- See Note [Inline @unzipN@ functions] in GHC/OldList.hs. mapAndUnzipM f xs = unzip <$> traverse f xs -- | The 'zipWithM' function generalizes 'zipWith' to arbitrary applicative functors. diff --git a/libraries/base/Data/OldList.hs b/libraries/base/Data/OldList.hs index 559823c4bd..132ee14673 100644 --- a/libraries/base/Data/OldList.hs +++ b/libraries/base/Data/OldList.hs @@ -929,8 +929,27 @@ foldr7_left _ z _ _ _ _ _ _ _ _ = z #-} +{- + +Note [Inline @unzipN@ functions] +~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ + +The inline principle for @unzip{4,5,6,7}@ is the same as 'unzip'/'unzip3' in +"GHC.List". +The 'unzip'/'unzip3' functions are inlined so that the `foldr` with which they +are defined has an opportunity to fuse. + +As such, since there are not any differences between 2/3-ary 'unzip' and its +n-ary counterparts below aside from the number of arguments, the `INLINE` +pragma should be replicated in the @unzipN@ functions below as well. + +-} + -- | The 'unzip4' function takes a list of quadruples and returns four -- lists, analogous to 'unzip'. +{-# INLINE unzip4 #-} +-- Inline so that fusion with `foldr` has an opportunity to fire. +-- See Note [Inline @unzipN@ functions] above. unzip4 :: [(a,b,c,d)] -> ([a],[b],[c],[d]) unzip4 = foldr (\(a,b,c,d) ~(as,bs,cs,ds) -> (a:as,b:bs,c:cs,d:ds)) @@ -938,6 +957,9 @@ unzip4 = foldr (\(a,b,c,d) ~(as,bs,cs,ds) -> -- | The 'unzip5' function takes a list of five-tuples and returns five -- lists, analogous to 'unzip'. +{-# INLINE unzip5 #-} +-- Inline so that fusion with `foldr` has an opportunity to fire. +-- See Note [Inline @unzipN@ functions] above. unzip5 :: [(a,b,c,d,e)] -> ([a],[b],[c],[d],[e]) unzip5 = foldr (\(a,b,c,d,e) ~(as,bs,cs,ds,es) -> (a:as,b:bs,c:cs,d:ds,e:es)) @@ -945,6 +967,9 @@ unzip5 = foldr (\(a,b,c,d,e) ~(as,bs,cs,ds,es) -> -- | The 'unzip6' function takes a list of six-tuples and returns six -- lists, analogous to 'unzip'. +{-# INLINE unzip6 #-} +-- Inline so that fusion with `foldr` has an opportunity to fire. +-- See Note [Inline @unzipN@ functions] above. unzip6 :: [(a,b,c,d,e,f)] -> ([a],[b],[c],[d],[e],[f]) unzip6 = foldr (\(a,b,c,d,e,f) ~(as,bs,cs,ds,es,fs) -> (a:as,b:bs,c:cs,d:ds,e:es,f:fs)) @@ -952,6 +977,9 @@ unzip6 = foldr (\(a,b,c,d,e,f) ~(as,bs,cs,ds,es,fs) -> -- | The 'unzip7' function takes a list of seven-tuples and returns -- seven lists, analogous to 'unzip'. +{-# INLINE unzip7 #-} +-- Inline so that fusion with `foldr` has an opportunity to fire. +-- See Note [Inline @unzipN@ functions] above. unzip7 :: [(a,b,c,d,e,f,g)] -> ([a],[b],[c],[d],[e],[f],[g]) unzip7 = foldr (\(a,b,c,d,e,f,g) ~(as,bs,cs,ds,es,fs,gs) -> (a:as,b:bs,c:cs,d:ds,e:es,f:fs,g:gs)) diff --git a/libraries/base/GHC/List.hs b/libraries/base/GHC/List.hs index 8f03ce3a08..d9b32ea9df 100644 --- a/libraries/base/GHC/List.hs +++ b/libraries/base/GHC/List.hs @@ -1128,12 +1128,16 @@ zipWith3FB cons func = \a b c r -> (func a b c) `cons` r -- and a list of second components. unzip :: [(a,b)] -> ([a],[b]) {-# INLINE unzip #-} +-- Inline so that fusion `foldr` has an opportunity to fire. +-- See Note [Inline @unzipN@ functions] in GHC/OldList.hs. unzip = foldr (\(a,b) ~(as,bs) -> (a:as,b:bs)) ([],[]) -- | The 'unzip3' function takes a list of triples and returns three -- lists, analogous to 'unzip'. unzip3 :: [(a,b,c)] -> ([a],[b],[c]) {-# INLINE unzip3 #-} +-- Inline so that fusion `foldr` has an opportunity to fire. +-- See Note [Inline @unzipN@ functions] in GHC/OldList.hs. unzip3 = foldr (\(a,b,c) ~(as,bs,cs) -> (a:as,b:bs,c:cs)) ([],[],[]) |