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| author | Joey Hess <joeyh@joeyh.name> | 2016-03-08 23:33:12 -0400 |
|---|---|---|
| committer | Joey Hess <joeyh@joeyh.name> | 2016-03-08 23:33:12 -0400 |
| commit | a08ec3412b45a49d3668a6d6439d1c81b05612ab (patch) | |
| tree | 86a3f0b77769cc21f19fe7d3ff61123e4ded073d /src | |
| parent | 30008bc643eeb8128f42734fe96d4f9010078558 (diff) | |
backported to ghc 7.6.3
Works on debian stable!
Diffstat (limited to 'src')
| -rw-r--r-- | src/Propellor/Types/OS/Typelevel.hs | 38 |
1 files changed, 30 insertions, 8 deletions
diff --git a/src/Propellor/Types/OS/Typelevel.hs b/src/Propellor/Types/OS/Typelevel.hs index 4803e4ac..0c2e76bf 100644 --- a/src/Propellor/Types/OS/Typelevel.hs +++ b/src/Propellor/Types/OS/Typelevel.hs @@ -14,8 +14,6 @@ module Propellor.Types.OS.TypeLevel ( import Network.BSD (HostName) import Data.Typeable import Data.String -import Data.Type.Bool -import Data.Type.Equality -- | A supported operating system. data SupportedOS = OSDebian | OSBuntish | OSFreeBSD @@ -86,11 +84,35 @@ type instance IntersectOSList (a ': rest) list2 = -- | Type level elem for OSList type family ElemOSList (a :: SupportedOS) (list :: [SupportedOS]) :: Bool -type instance ElemOSList a '[] = False -type instance ElemOSList a (b ': bs) = a == b || ElemOSList a bs +type instance ElemOSList a '[] = 'False +type instance ElemOSList a (b ': bs) = EqOS a b || ElemOSList a bs -- | Type level equality for SupportedOS -type family EqOS (a :: SupportedOS) (b :: SupportedOS) where - EqOS a a = True - EqOS a b = False -type instance a == b = EqOS a b +-- +-- This is a very clumsy implmentation, but it works back to ghc 7.6. +type family EqOS (a :: SupportedOS) (b :: SupportedOS) :: Bool +type instance EqOS OSDebian OSDebian = 'True +type instance EqOS OSBuntish OSBuntish = 'True +type instance EqOS OSFreeBSD OSFreeBSD = 'True +type instance EqOS OSDebian OSBuntish = 'False +type instance EqOS OSDebian OSFreeBSD = 'False +type instance EqOS OSBuntish OSDebian = 'False +type instance EqOS OSBuntish OSFreeBSD = 'False +type instance EqOS OSFreeBSD OSDebian = 'False +type instance EqOS OSFreeBSD OSBuntish = 'False +-- More modern version if the combinatiorial explosion gets too bad later: +-- +-- type family EqOS (a :: SupportedOS) (b :: SupportedOS) where +-- EqOS a a = True +-- EqOS a b = False + +-- | This is in Data.Type.Bool with modern versions of ghc, but is included +-- here to support ghc 7.6. +type family If (cond :: Bool) (tru :: a) (fls :: a) :: a +type instance If 'True tru fls = tru +type instance If 'False tru fls = fls +type family (a :: Bool) || (b :: Bool) :: Bool +type instance 'False || 'False = 'False +type instance 'True || 'True = 'True +type instance 'True || 'False = 'True +type instance 'False || 'True = 'True |