Merge pull request #3 from jdegoes/ready/char-instance

add Enum instance for Char, fix all versions

Author: paf31

README.md

@@ -22,6 +22,8 @@
 
     instance enumBoolean :: Enum Boolean
 
+    instance enumChar :: Enum Char
+
     instance enumMaybe :: (Enum a) => Enum (Maybe a)
 
     instance enumTuple :: (Enum a, Enum b) => Enum (Tuple a b)

bower.json

@@ -18,7 +18,8 @@
     "package.json"
   ],
   "dependencies": {
-    "purescript-maybe":  "*",
-    "purescript-tuples": "*"
+    "purescript-maybe":   "~0.2.1",
+    "purescript-tuples":  "~0.2.1",
+    "purescript-strings": "~0.3.2"
   }
 }

src/Data/Enum.purs

@@ -13,6 +13,7 @@ module Data.Enum
 
   import Data.Maybe
   import Data.Tuple
+  import Data.Char
   import Data.Maybe.Unsafe
 
   newtype Cardinality a = Cardinality Number 
@@ -55,6 +56,17 @@ module Data.Enum
   maybeCardinality :: forall a. (Enum a) => Cardinality a -> Cardinality (Maybe a)
   maybeCardinality c = Cardinality $ 1 + (runCardinality c)
 
+  instance enumChar :: Enum Char where
+    cardinality = Cardinality (65535 + 1)
+
+    firstEnum = fromCharCode 0
+
+    lastEnum = fromCharCode 65535
+
+    succ c = if c == lastEnum then Nothing else Just $ (fromCharCode <<< ((+) 1) <<< toCharCode) c
+
+    pred c = if c == firstEnum then Nothing else Just $ (fromCharCode <<< ((+) (-1)) <<< toCharCode) c
+
   instance enumMaybe :: (Enum a) => Enum (Maybe a) where
     cardinality = maybeCardinality cardinality