diff options
Diffstat (limited to 'libraries/base/GHC/Exts.hs')
| -rwxr-xr-x | libraries/base/GHC/Exts.hs | 42 |
1 files changed, 40 insertions, 2 deletions
diff --git a/libraries/base/GHC/Exts.hs b/libraries/base/GHC/Exts.hs index f6204aabd4..9fc1a638fc 100755 --- a/libraries/base/GHC/Exts.hs +++ b/libraries/base/GHC/Exts.hs @@ -34,6 +34,9 @@ module GHC.Exts uncheckedIShiftL64#, uncheckedIShiftRA64#, isTrue#, + -- * Compat wrapper + atomicModifyMutVar#, + -- * Fusion build, augment, @@ -46,7 +49,7 @@ module GHC.Exts -- * Ids with special behaviour lazy, inline, oneShot, - -- * Running 'RealWorld' state transformers + -- * Running 'RealWorld' state thread runRW#, -- * Safe coercions @@ -154,7 +157,9 @@ traceEvent = Debug.Trace.traceEventIO -- entire ghc package at runtime data SpecConstrAnnotation = NoSpecConstr | ForceSpecConstr - deriving( Data, Eq ) + deriving ( Data -- ^ @since 4.3.0.0 + , Eq -- ^ @since 4.3.0.0 + ) {- ********************************************************************** @@ -194,6 +199,15 @@ instance IsList [a] where fromList = id toList = id +-- | @since 4.9.0.0 +instance IsList (NonEmpty a) where + type Item (NonEmpty a) = a + + fromList (a:as) = a :| as + fromList [] = errorWithoutStackTrace "NonEmpty.fromList: empty list" + + toList ~(a :| as) = a : as + -- | @since 4.8.0.0 instance IsList Version where type (Item Version) = Int @@ -208,3 +222,27 @@ instance IsList CallStack where type (Item CallStack) = (String, SrcLoc) fromList = fromCallSiteList toList = getCallStack + +-- | An implementation of the old @atomicModifyMutVar#@ primop in +-- terms of the new 'atomicModifyMutVar2#' primop, for backwards +-- compatibility. The type of this function is a bit bogus. It's +-- best to think of it as having type +-- +-- @ +-- atomicModifyMutVar# +-- :: MutVar# s a +-- -> (a -> (a, b)) +-- -> State# s +-- -> (# State# s, b #) +-- @ +-- +-- but there may be code that uses this with other two-field record +-- types. +atomicModifyMutVar# + :: MutVar# s a + -> (a -> b) + -> State# s + -> (# State# s, c #) +atomicModifyMutVar# mv f s = + case unsafeCoerce# (atomicModifyMutVar2# mv f s) of + (# s', _, ~(_, res) #) -> (# s', res #) |