Add any function (#34)

This is a specialized version of `Data.Foldable.any` that can short-circuit.

Co-authored-by: Stefan Fehrenbach <stefan.fehrenbach@gmail.com>

.gitignore

@@ -7,3 +7,4 @@
 /.purs*
 /.psa*
 test-bundle.js
+.spago

src/Data/HashMap.js

@@ -477,6 +477,26 @@ MapNode.prototype.itraverse = function (pure, apply, f) {
     return m;
 }
 
+MapNode.prototype.any = function (predicate) {
+  for (var i = 1; i < popCount(this.datamap) * 2; i = i + 2) {
+    var v = this.content[i];
+
+    if (predicate(v)) {
+        return true;
+    }
+  }
+
+  i--;
+
+  for (; i < this.content.length; i++) {
+    if (this.content[i].any(predicate)) {
+      return true;
+    }
+  }
+
+  return false;
+};
+
 /** @constructor */
 function Collision(keys, values) {
     this.keys = keys;
@@ -679,6 +699,15 @@ Collision.prototype.filterWithKey = function collisionFilterWithKey(f) {
     return new Collision(keys, values);
 }
 
+Collision.prototype.any = function (predicate) {
+  for (var i = 0; i < this.keys.length; i++) {
+    if (predicate(this.values[i])) {
+      return true;
+    }
+  }
+  return false;
+};
+
 function mask(keyHash, shift) {
     return 1 << ((keyHash >>> shift) & 31);
 }
@@ -917,3 +946,9 @@ export function nubHashPurs(Nothing, Just, eq, hash) {
         return r;
     };
 };
+
+export function anyPurs(pred) {
+  return function (m) {
+      return m.any(pred);
+  };
+};

src/Data/HashMap.purs

@@ -46,7 +46,9 @@ module Data.HashMap (
 
   nubHash,
 
-  debugShow
+  debugShow,
+
+  any
   ) where
 
 import Prelude
@@ -407,3 +409,11 @@ nubHash :: forall a. Hashable a => Array a -> Array a
 nubHash = runFn4 nubHashPurs Nothing Just (==) hash
 
 foreign import nubHashPurs :: forall a. Fn4 (forall x. Maybe x) (forall x. x -> Maybe x) (a -> a -> Boolean) (a -> Int) (Array a -> Array a)
+
+foreign import anyPurs :: forall k v. (v -> Boolean) -> HashMap k v -> Boolean
+
+-- | Returns true if at least one HashMap element satisfies the given predicate, iterating the HashMap only as necessary and stopping as soon as the predicate yields true.
+-- |
+-- | Use this function instead of `Foldable.any` for more performance.
+any :: forall k v. (v -> Boolean) -> HashMap k v -> Boolean
+any = anyPurs

test/Main.purs

@@ -9,7 +9,7 @@ import Prelude
 import Data.Array as A
 import Data.Array as Array
 import Data.Array.NonEmpty (fromNonEmpty)
-import Data.Foldable (all, foldMap, foldl, foldr)
+import Data.Foldable (all, foldMap, foldl, foldr, any)
 import Data.FoldableWithIndex (allWithIndex, foldMapWithIndex, foldlWithIndex, foldrWithIndex)
 import Data.HashMap (HashMap)
 import Data.HashMap as HM
@@ -437,6 +437,26 @@ main = do
       Just false -> HM.lookup k mc === HM.lookup k my
       Nothing -> false === HM.member k my
 
+  log "any"
+  quickCheck' 10000 $ \(a :: Array (Tuple Int Int)) ->
+    let hm = HM.fromFoldable a
+        xs = HM.toArrayBy Tuple hm
+    in  (not (HM.any (\_ -> true) HM.empty)) &&
+        case A.head xs of
+          Nothing -> true
+          Just h  -> case A.last xs of
+            Nothing -> true
+            Just l  -> HM.any (\x -> x == snd h) hm
+                    && HM.any (\x -> x == snd l) hm
+                    && (not (HM.any (\_ -> false) hm))
+
+  log "any agrees with Foldable any"
+  quickCheck' 10000 $ \(a :: Array (Tuple CollidingInt Int)) (f :: Int -> Boolean) ->
+    let m = HM.fromArray a
+        f' (Tuple _ v) = f v
+    -- use array instance, so we still test something useful if any ever becomes a method on Foldable
+    in  any f' a === HM.any f m
+
   log "Done."
 
 t54 :: Boolean