Merge pull request #2 from LiamGoodacre/feature/compare-append-symbol

Add CompareSymbol and AppendSymbol

Author: paf31

src/Type/Data/Symbol.purs

@@ -0,0 +1,30 @@
+module Type.Data.Symbol
+  ( module Data.Symbol
+  , class CompareSymbol
+  , compareSymbol
+  , class AppendSymbol
+  , appendSymbol
+  ) where
+
+import Data.Symbol (SProxy(..), class IsSymbol, reflectSymbol, reifySymbol)
+import Type.Data.Ordering (OProxy(..), kind Ordering)
+
+-- | Compare two `Symbol` types
+class CompareSymbol (lhs :: Symbol)
+                    (rhs :: Symbol)
+                    (out :: Ordering) |
+                    lhs rhs -> out
+
+compareSymbol :: forall l r o. CompareSymbol l r o => SProxy l -> SProxy r -> OProxy o
+compareSymbol _ _ = OProxy
+
+
+-- | Append two `Symbol` types together
+class AppendSymbol (lhs :: Symbol)
+                   (rhs :: Symbol)
+                   (out :: Symbol) |
+                   lhs rhs -> out
+
+appendSymbol :: forall l r o. AppendSymbol l r o => SProxy l -> SProxy r -> SProxy o
+appendSymbol _ _ = SProxy
+

src/Type/Prelude.purs

@@ -2,10 +2,10 @@ module Type.Prelude
   ( module Type.Equality
   , module Type.Data.Ordering
   , module Type.Proxy
-  , module Data.Symbol
+  , module Type.Data.Symbol
   ) where
 
 import Type.Equality (class TypeEquals, from, to)
 import Type.Data.Ordering (kind Ordering, LT, EQ, GT, OProxy(..), class IsOrdering, reflectOrdering, reifyOrdering)
 import Type.Proxy (Proxy(..))
-import Data.Symbol (SProxy(..), class IsSymbol, reflectSymbol, reifySymbol)
+import Type.Data.Symbol (SProxy(..), class IsSymbol, reflectSymbol, reifySymbol, class CompareSymbol, compareSymbol, class AppendSymbol, appendSymbol)