Merge pull request #31 from LiamGoodacre/master

`fromFoldable` generalised `fromList`

Author: paf31

bower.json

@@ -23,5 +23,9 @@
   ],
   "dependencies": {
     "purescript-maps": "^0.5.0"
+  },
+  "devDependencies": {
+    "purescript-assert": "~0.1.1",
+    "purescript-console": "~0.1.1"
   }
 }

docs/Data/Set.md

@@ -15,12 +15,12 @@ data Set a
 
 ##### Instances
 ``` purescript
-instance eqSet :: (Eq a) => Eq (Set a)
-instance showSet :: (Show a) => Show (Set a)
-instance ordSet :: (Ord a) => Ord (Set a)
-instance monoidSet :: (Ord a) => Monoid (Set a)
-instance semigroupSet :: (Ord a) => Semigroup (Set a)
-instance foldableSet :: Foldable Set
+(Eq a) => Eq (Set a)
+(Show a) => Show (Set a)
+(Ord a) => Ord (Set a)
+(Ord a) => Monoid (Set a)
+(Ord a) => Semigroup (Set a)
+Foldable Set
 ```
 
 #### `empty`
@@ -81,6 +81,14 @@ delete :: forall a. (Ord a) => a -> Set a -> Set a
 
 Delete a value from a set
 
+#### `fromFoldable`
+
+``` purescript
+fromFoldable :: forall f a. (Foldable f, Ord a) => f a -> Set a
+```
+
+Create a set from a foldable collection of elements
+
 #### `toList`
 
 ``` purescript

package.json

@@ -2,7 +2,7 @@
   "private": true,
   "scripts": {
     "postinstall": "pulp dep install",
-    "build": "pulp build && rimraf docs && pulp docs"
+    "build": "pulp build && pulp test && rimraf docs && pulp docs"
   },
   "devDependencies": {
     "pulp": "^4.0.2",

src/Data/Set.purs

@@ -12,6 +12,7 @@ module Data.Set
   , insert
   , member
   , delete
+  , fromFoldable
   , toList
   , fromList
   , size
@@ -81,13 +82,17 @@ insert a (Set m) = Set (M.insert a unit m)
 delete :: forall a. (Ord a) => a -> Set a -> Set a
 delete a (Set m) = Set (a `M.delete` m)
 
+-- | Create a set from a foldable collection of elements
+fromFoldable :: forall f a. (Foldable f, Ord a) => f a -> Set a
+fromFoldable = foldl (\m a -> insert a m) empty
+
 -- | Convert a set to a list
 toList :: forall a. Set a -> List a
 toList (Set m) = map fst (M.toList m)
 
 -- | Create a set from a list of elements
 fromList :: forall a. (Ord a) => List a -> Set a
-fromList = foldl (\m a -> insert a m) empty
+fromList = fromFoldable
 
 -- | Find the size of a set
 size :: forall a. Set a -> Int

test/Test/Main.purs

@@ -0,0 +1,20 @@
+module Test.Main where
+
+import Prelude
+
+import Control.Monad.Eff.Console (log)
+import Test.Assert (assert)
+
+import Data.Set (Set())
+import Data.Set as S
+
+main = do
+  log "fromFoldable - empty"
+  assert $ S.fromFoldable [] == S.empty :: Set Unit
+
+  log "fromFoldable - non empty"
+  do let set = S.fromFoldable [0, 1, 1, 2]
+     assert $ S.size set == 3
+     assert $ S.member 0 set
+     assert $ S.member 1 set
+     assert $ S.member 2 set