git.iko.soy/type-fun
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CHANGELOG.md+7 example/Main.hs+1 src/TypeFun/Data/Peano.hs+14−3 stack.yaml+9 stack.yaml.lock+12 type-fun.cabal+2−2
CHANGELOG.md+7
@@ -4,6 +4,13 @@
44
55# CHANGELOG
66
7+## 0.1.2
8+### Added KnownPeano
9+
10+## 0.1.1
11+### Fixed
12+* Compilable with ghc-8.0.1
13+
714## 0.1.0
815### Added
916* Type family `Substract` to remove elements of one list from another
example/Main.hs+1
@@ -37,4 +37,5 @@ main = do
3737 print $ prefixConstr p2
3838 print $ prefixConstr p3
3939 print $ uniqConstr p2
40+ print $ peanoVal (Proxy :: Proxy (FromNat 100))
4041 -- print $ uniqConstr p3 -- < ElementIsNotUniqInList Int '[Int, Bool, Int]
src/TypeFun/Data/Peano.hs+14−3
@@ -1,5 +1,6 @@
11module TypeFun.Data.Peano
22 ( N(..)
3+ , KnownPeano(..)
34 , ToNat
45 , FromNat
56 , (:+:)
@@ -7,14 +8,24 @@ module TypeFun.Data.Peano
78 , (:*:)
89 ) where
910
10−import Data.Typeable
11−import GHC.Generics (Generic)
12−import GHC.TypeLits
11+import Data.Typeable
12+import GHC.Generics (Generic)
13+import GHC.TypeLits
1314
1415data N = Z | S N
1516 deriving ( Eq, Ord, Read, Show
1617 , Generic, Typeable )
1718
19+-- | @since 0.1.2
20+class KnownPeano (p :: N) where
21+ peanoVal :: proxy p -> Integer
22+
23+instance KnownPeano Z where
24+ peanoVal _ = 0
25+
26+instance (KnownPeano n) => KnownPeano (S n) where
27+ peanoVal _ = succ $ peanoVal (Proxy :: Proxy n)
28+
1829type family ToNat (a :: N) :: Nat where
1930 ToNat Z = 0
2031 ToNat (S a) = 1 + (ToNat a)
stack.yamlnew file+9
@@ -0,0 +1,9 @@
1+nix:
2+ packages:
3+ - zlib
4+ - postgresql
5+
6+resolver: lts-13.21
7+
8+packages:
9+ - .
stack.yaml.locknew file+12
@@ -0,0 +1,12 @@
1+# This file was autogenerated by Stack.
2+# You should not edit this file by hand.
3+# For more information, please see the documentation at:
4+# https://docs.haskellstack.org/en/stable/lock_files
5+
6+packages: []
7+snapshots:
8+- completed:
9+ size: 498180
10+ url: https://raw.githubusercontent.com/commercialhaskell/stackage-snapshots/master/lts/13/21.yaml
11+ sha256: eff2de19a6d4691ccbf6edc1fba858f1918683047dce0f09adede874bbd2a8f3
12+ original: lts-13.21
type-fun.cabal+2−2
@@ -1,5 +1,5 @@
11name: type-fun
2−version: 0.1.0
2+version: 0.1.2
33synopsis: Collection of widely reimplemented type families
44license: BSD3
55license-file: LICENSE
@@ -36,7 +36,7 @@ library
3636 , TypeFun.Data.Maybe
3737 , TypeFun.Data.Peano
3838
39− build-depends: base >=4.7 && <4.9
39+ build-depends: base >= 4.7 && < 5
4040
4141test-suite example
4242 type: exitcode-stdio-1.0