Add minimum and maximum to Data.Semigroup.Foldable

These are handy because, unlike `Data.Foldable` they don't return a `Maybe`.

Author: colehaus

bower.json

@@ -18,7 +18,8 @@
   ],
   "dependencies": {
     "purescript-bifunctors": "^3.0.0",
-    "purescript-maybe": "^3.0.0"
+    "purescript-maybe": "^3.0.0",
+    "purescript-orders": "^3.0.0"
   },
   "devDependencies": {
     "purescript-assert": "^3.0.0",

src/Data/Semigroup/Foldable.purs

@@ -13,6 +13,9 @@ import Prelude
 import Data.Foldable (class Foldable)
 import Data.Monoid.Dual (Dual(..))
 import Data.Monoid.Multiplicative (Multiplicative(..))
+import Data.Newtype (ala)
+import Data.Ord.Max (Max(..))
+import Data.Ord.Min (Min(..))
 
 -- | `Foldable1` represents data structures with a minimum of one element that can be _folded_.
 -- |
@@ -71,3 +74,9 @@ for1_ = flip traverse1_
 -- | given by the `Foldable1` instance, ignoring the final result.
 sequence1_ :: forall t f a. Foldable1 t => Apply f => t (f a) -> f Unit
 sequence1_ = traverse1_ id
+
+maximum :: forall f a. Ord a => Foldable1 f => f a -> a
+maximum = ala Max foldMap1
+
+minimum :: forall f a. Ord a => Foldable1 f => f a -> a
+minimum = ala Min foldMap1