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| author | Simon Peyton Jones <simonpj@microsoft.com> | 2017-12-13 10:49:31 +0000 |
|---|---|---|
| committer | Simon Peyton Jones <simonpj@microsoft.com> | 2017-12-13 10:52:10 +0000 |
| commit | 321b420f4582d103ca7b304867b916a749712e9f (patch) | |
| tree | 2e76c23cca162b2d00da9b52c73f42bc559a0089 /libraries/base/GHC/Base.hs | |
| parent | e40db7b1676627f5291b463405338e7b69fa3f69 (diff) | |
| download | haskell-321b420f4582d103ca7b304867b916a749712e9f.tar.gz | |
Tidy up of wired-in names
Two things here:
* While debugging Trac #14561 I found it hard to understand
ghcPrimIds and magicIds in MkId. This patch adds more
structure and comments.
* I also discovered that ($) no longer needs to be a wiredInId
because we now have levity polymorphism. So I took dollarId
out of MkId; and gave it a levity-polymorphic type in GHC.Base
Diffstat (limited to 'libraries/base/GHC/Base.hs')
| -rw-r--r-- | libraries/base/GHC/Base.hs | 9 |
1 files changed, 7 insertions, 2 deletions
diff --git a/libraries/base/GHC/Base.hs b/libraries/base/GHC/Base.hs index 2d6e0e4195..35de446ca6 100644 --- a/libraries/base/GHC/Base.hs +++ b/libraries/base/GHC/Base.hs @@ -83,6 +83,7 @@ Other Prelude modules are much easier with fewer complex dependencies. , UnboxedTuples , ExistentialQuantification , RankNTypes + , KindSignatures #-} -- -Wno-orphans is needed for things like: -- Orphan rule: "x# -# x#" ALWAYS forall x# :: Int# -# x# x# = 0 @@ -1287,9 +1288,13 @@ flip f x y = f y x -- -- It is also useful in higher-order situations, such as @'map' ('$' 0) xs@, -- or @'Data.List.zipWith' ('$') fs xs@. +-- +-- Note that @($)@ is levity-polymorphic in its result type, so that +-- foo $ True where foo :: Bool -> Int# +-- is well-typed {-# INLINE ($) #-} -($) :: (a -> b) -> a -> b -f $ x = f x +($) :: forall r a (b :: TYPE r). (a -> b) -> a -> b +f $ x = f x -- | Strict (call-by-value) application operator. It takes a function and an -- argument, evaluates the argument to weak head normal form (WHNF), then calls |