Merge pull request #3158 from gagandeepkalra/functorFilter/addFilterN…

…otFunction

add `filterNot` to FunctorFilter

core/src/main/scala-2.12/cats/instances/stream.scala

@@ -192,6 +192,8 @@ private[instances] trait StreamInstancesBinCompat0 {
 
     override def filter[A](fa: Stream[A])(f: (A) => Boolean): Stream[A] = fa.filter(f)
 
+    override def filterNot[A](fa: Stream[A])(f: A => Boolean): Stream[A] = fa.filterNot(f)
+
     override def collect[A, B](fa: Stream[A])(f: PartialFunction[A, B]): Stream[B] = fa.collect(f)
 
     override def flattenOption[A](fa: Stream[Option[A]]): Stream[A] = fa.flatten

core/src/main/scala-2.13+/cats/instances/lazyList.scala

@@ -154,6 +154,8 @@ trait LazyListInstances extends cats.kernel.instances.LazyListInstances {
 
     override def filter[A](fa: LazyList[A])(f: (A) => Boolean): LazyList[A] = fa.filter(f)
 
+    override def filterNot[A](fa: LazyList[A])(f: (A) => Boolean): LazyList[A] = fa.filterNot(f)
+
     override def collect[A, B](fa: LazyList[A])(f: PartialFunction[A, B]): LazyList[B] = fa.collect(f)
 
     override def flattenOption[A](fa: LazyList[Option[A]]): LazyList[A] = fa.flatten

core/src/main/scala/cats/FunctorFilter.scala

@@ -66,4 +66,11 @@ trait FunctorFilter[F[_]] extends Serializable {
    */
   def filter[A](fa: F[A])(f: A => Boolean): F[A] =
     mapFilter(fa)(a => if (f(a)) Some(a) else None)
+
+  /**
+   * Apply a filter to a structure such that the output structure contains all
+   * `A` elements in the input structure that do not satisfy the predicate `f`.
+   */
+  def filterNot[A](fa: F[A])(f: A => Boolean): F[A] =
+    mapFilter(fa)(Some(_).filterNot(f))
 }

core/src/main/scala/cats/data/Chain.scala

@@ -799,6 +799,8 @@ sealed abstract private[data] class ChainInstances extends ChainInstances1 {
 
     override def filter[A](fa: Chain[A])(f: A => Boolean): Chain[A] = fa.filter(f)
 
+    override def filterNot[A](fa: Chain[A])(f: A => Boolean): Chain[A] = fa.filterNot(f)
+
     override def collect[A, B](fa: Chain[A])(f: PartialFunction[A, B]): Chain[B] = fa.collect(f)
 
     override def mapFilter[A, B](fa: Chain[A])(f: A => Option[B]): Chain[B] = fa.collect(Function.unlift(f))

core/src/main/scala/cats/data/Const.scala

@@ -107,6 +107,8 @@ sealed abstract private[data] class ConstInstances extends ConstInstances0 {
 
     override def filter[A](fa: Const[C, A])(f: (A) => Boolean): Const[C, A] = fa.retag
 
+    override def filterNot[A](fa: Const[C, A])(f: A => Boolean): Const[C, A] = fa.retag
+
     def traverseFilter[G[_], A, B](
       fa: Const[C, A]
     )(f: (A) => G[Option[B]])(implicit G: Applicative[G]): G[Const[C, B]] =

core/src/main/scala/cats/data/Nested.scala

@@ -369,6 +369,10 @@ abstract private[data] class NestedFunctorFilter[F[_], G[_]] extends FunctorFilt
 
   override def filter[A](fa: Nested[F, G, A])(f: (A) => Boolean): Nested[F, G, A] =
     Nested[F, G, A](F.map(fa.value)(G.filter(_)(f)))
+
+  override def filterNot[A](fa: Nested[F, G, A])(f: A => Boolean): Nested[F, G, A] =
+    Nested[F, G, A](F.map(fa.value)(G.filterNot(_)(f)))
+
 }
 
 abstract private[data] class NestedTraverseFilter[F[_], G[_]]

core/src/main/scala/cats/data/OptionT.scala

@@ -497,6 +497,8 @@ sealed private[data] trait OptionTFunctorFilter[F[_]] extends FunctorFilter[Opti
   override def flattenOption[A](fa: OptionT[F, Option[A]]): OptionT[F, A] = fa.subflatMap(identity)
 
   override def filter[A](fa: OptionT[F, A])(f: (A) => Boolean): OptionT[F, A] = fa.filter(f)
+
+  override def filterNot[A](fa: OptionT[F, A])(f: A => Boolean): OptionT[F, A] = fa.filterNot(f)
 }
 
 sealed private[data] trait OptionTOrder[F[_], A] extends Order[OptionT[F, A]] with OptionTPartialOrder[F, A] {

core/src/main/scala/cats/instances/list.scala

@@ -193,6 +193,8 @@ private[instances] trait ListInstancesBinCompat0 {
 
     override def filter[A](fa: List[A])(f: (A) => Boolean): List[A] = fa.filter(f)
 
+    override def filterNot[A](fa: List[A])(f: A => Boolean): List[A] = fa.filterNot(f)
+
     override def collect[A, B](fa: List[A])(f: PartialFunction[A, B]): List[B] = fa.collect(f)
 
     override def flattenOption[A](fa: List[Option[A]]): List[A] = fa.flatten

core/src/main/scala/cats/instances/map.scala

@@ -157,6 +157,9 @@ private[instances] trait MapInstancesBinCompat0 {
       override def filter[A](fa: Map[K, A])(f: A => Boolean) =
         fa.filter { case (_, v) => f(v) }
 
+      override def filterNot[A](fa: Map[K, A])(f: A => Boolean): Map[K, A] =
+        fa.filterNot { case (_, v) => f(v) }
+
     }
 
 }

core/src/main/scala/cats/instances/option.scala

@@ -168,6 +168,8 @@ private[instances] trait OptionInstancesBinCompat0 {
 
     override def filter[A](fa: Option[A])(f: (A) => Boolean): Option[A] = fa.filter(f)
 
+    override def filterNot[A](fa: Option[A])(f: A => Boolean): Option[A] = fa.filterNot(f)
+
     override def collect[A, B](fa: Option[A])(f: PartialFunction[A, B]): Option[B] = fa.collect(f)
 
     override def flattenOption[A](fa: Option[Option[A]]): Option[A] = fa.flatten

core/src/main/scala/cats/instances/queue.scala

@@ -165,6 +165,8 @@ private object QueueInstances {
 
     override def filter[A](fa: Queue[A])(f: (A) => Boolean): Queue[A] = fa.filter(f)
 
+    override def filterNot[A](fa: Queue[A])(f: A => Boolean): Queue[A] = fa.filterNot(f)
+
     override def collect[A, B](fa: Queue[A])(f: PartialFunction[A, B]): Queue[B] = fa.collect(f)
 
     override def flattenOption[A](fa: Queue[Option[A]]): Queue[A] = fa.flatten

core/src/main/scala/cats/instances/sortedMap.scala

@@ -205,6 +205,9 @@ private[instances] trait SortedMapInstancesBinCompat0 {
       override def filter[A](fa: SortedMap[K, A])(f: (A) => Boolean): SortedMap[K, A] =
         fa.filter { case (_, v) => f(v) }
 
+      override def filterNot[A](fa: SortedMap[K, A])(f: A => Boolean): SortedMap[K, A] =
+        fa.filterNot { case (_, v) => f(v) }
+
       override def filterA[G[_], A](
         fa: SortedMap[K, A]
       )(f: (A) => G[Boolean])(implicit G: Applicative[G]): G[SortedMap[K, A]] =

core/src/main/scala/cats/instances/vector.scala

@@ -158,6 +158,8 @@ private[instances] trait VectorInstancesBinCompat0 {
 
     override def filter[A](fa: Vector[A])(f: (A) => Boolean): Vector[A] = fa.filter(f)
 
+    override def filterNot[A](fa: Vector[A])(f: A => Boolean): Vector[A] = fa.filterNot(f)
+
     override def collect[A, B](fa: Vector[A])(f: PartialFunction[A, B]): Vector[B] = fa.collect(f)
 
     override def flattenOption[A](fa: Vector[Option[A]]): Vector[A] = fa.flatten

laws/src/main/scala/cats/laws/FunctorFilterLaws.scala

@@ -24,6 +24,9 @@ trait FunctorFilterLaws[F[_]] {
   def filterConsistentWithMapFilter[A](fa: F[A], f: A => Boolean): IsEq[F[A]] =
     F.filter(fa)(f) <->
       F.mapFilter(fa)(a => if (f(a)) Some(a) else None)
+
+  def filterNotConsistentWithFilter[A](fa: F[A], f: A => Boolean): IsEq[F[A]] =
+    F.filterNot(fa)(f) <-> F.filter(fa)(!f(_))
 }
 
 object FunctorFilterLaws {

laws/src/main/scala/cats/laws/discipline/FunctorFilterTests.scala

@@ -27,7 +27,8 @@ trait FunctorFilterTests[F[_]] extends Laws {
       "mapFilter map consistency" -> forAll(laws.mapFilterMapConsistency[A, B] _),
       "collect mapFilter consistency" -> forAll(laws.collectConsistentWithMapFilter[A, B] _),
       "flattenOption mapFilter consistency" -> forAll(laws.flattenOptionConsistentWithMapFilter[A] _),
-      "filter mapFilter consistency" -> forAll(laws.filterConsistentWithMapFilter[A] _)
+      "filter mapFilter consistency" -> forAll(laws.filterConsistentWithMapFilter[A] _),
+      "filterNot mapFilter consistency" -> forAll(laws.filterNotConsistentWithFilter[A] _)
     )
 }