Merge pull request #97 from matthewleon/nonempty-funcs

sorting for NonEmptyList

Author: paf31

bower.json

@@ -23,7 +23,8 @@
     "purescript-lazy": "^3.0.0",
     "purescript-nonempty": "^4.0.0",
     "purescript-tailrec": "^3.0.0",
-    "purescript-unfoldable": "^3.0.0"
+    "purescript-unfoldable": "^3.0.0",
+    "purescript-partial": "^1.0.0"
   },
   "devDependencies": {
     "purescript-arrays": "^4.0.0",

src/Data/List/NonEmpty.purs

@@ -13,6 +13,8 @@ module Data.List.NonEmpty
   , length
   , concatMap
   , appendFoldable
+  , sort
+  , sortBy
   ) where
 
 import Prelude
@@ -21,11 +23,12 @@ import Data.Foldable (class Foldable)
 import Data.List ((:))
 import Data.List as L
 import Data.List.Types (NonEmptyList(..))
-import Data.Maybe (Maybe(..), maybe, fromMaybe)
+import Data.Maybe (Maybe(..), maybe, fromMaybe, fromJust)
 import Data.NonEmpty ((:|))
 import Data.NonEmpty as NE
 import Data.Tuple (Tuple(..))
 import Data.Unfoldable (class Unfoldable, unfoldr)
+import Partial.Unsafe (unsafePartial)
 
 toUnfoldable :: forall f. Unfoldable f => NonEmptyList ~> f
 toUnfoldable =
@@ -68,3 +71,10 @@ concatMap = flip bind
 appendFoldable :: forall t a. Foldable t => NonEmptyList a -> t a -> NonEmptyList a
 appendFoldable (NonEmptyList (x :| xs)) ys =
   NonEmptyList (x :| (xs <> L.fromFoldable ys))
+
+sort :: forall a. Ord a => NonEmptyList a -> NonEmptyList a
+sort xs = sortBy compare xs
+
+sortBy :: forall a. (a -> a -> Ordering) -> NonEmptyList a -> NonEmptyList a
+sortBy cmp xs = unsafeFromList $ L.sortBy cmp (toList xs)
+  where unsafeFromList ys = unsafePartial $ fromJust $ fromList ys

test/Test/Data/List/NonEmpty.purs

@@ -0,0 +1,19 @@
+module Test.Data.List.NonEmpty (testNonEmptyList) where
+
+import Prelude
+import Data.List (fromFoldable)
+import Data.List.NonEmpty (NonEmptyList(..), sort, sortBy)
+import Data.NonEmpty ((:|))
+import Control.Monad.Eff (Eff)
+import Control.Monad.Eff.Console (CONSOLE, log)
+import Test.Assert (ASSERT, assert)
+
+testNonEmptyList ::
+  forall eff. Eff (assert :: ASSERT, console :: CONSOLE | eff) Unit
+testNonEmptyList = do
+  let nel x xs = NonEmptyList $ x :| fromFoldable xs
+
+  log "sort should reorder a non-empty list into ascending order based on the result of compare"
+  assert $ sort (nel 1 [3, 2, 5, 6, 4]) == nel 1 [2, 3, 4, 5, 6]
+  log "sortBy should reorder a non-empty list into ascending order based on the result of a comparison function"
+  assert $ sortBy (flip compare) (nel 1 [3, 2, 5, 6, 4]) == nel 6 [5, 4, 3, 2, 1]

test/Test/Main.purs

@@ -10,10 +10,12 @@ import Test.Data.List (testList)
 import Test.Data.List.Lazy (testListLazy)
 import Test.Data.List.Partial (testListPartial)
 import Test.Data.List.ZipList (testZipList)
+import Test.Data.List.NonEmpty (testNonEmptyList)
 
 main :: forall eff. Eff (assert :: ASSERT, console :: CONSOLE | eff) Unit
 main = do
   testList
   testListLazy
   testZipList
   testListPartial
+  testNonEmptyList