Add foldl and foldr aliases to Foldable

typelevel · Nov 7, 2017 · 51a577d · 51a577d
1 parent 93dc315
commit 51a577d
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Showing 2 changed files with 11 additions and 3 deletions.
diff --git a/core/src/main/scala/cats/syntax/foldable.scala b/core/src/main/scala/cats/syntax/foldable.scala
@@ -2,11 +2,11 @@ package cats
 package syntax
 
 trait FoldableSyntax1 {
-  implicit def foldableSyntaxU[FA](fa: FA)(implicit U: Unapply[Foldable,FA]): Foldable.Ops[U.M, U.A] =
-    new Foldable.Ops[U.M, U.A] {
+  implicit def foldableSyntaxU[FA](fa: FA)(implicit U: Unapply[Foldable,FA]): FoldableOps[U.M, U.A] =
+    new FoldableOps[U.M, U.A] {
       val self = U.subst(fa)
       val typeClassInstance = U.TC
-      }
+    }
 }
 
 trait FoldableSyntax extends Foldable.ToFoldableOps with FoldableSyntax1 {
@@ -33,3 +33,9 @@ final class NestedFoldableOps[F[_], G[_], A](fga: F[G[A]])(implicit F: Foldable[
    */
   def foldK(implicit G: MonoidK[G]): G[A] = F.foldK(fga)
 }
+
+abstract class FoldableOps[F[_], A] extends Foldable.Ops[F, A] {
+  def foldl[B](b: B)(f: (B, A) => B): B = typeClassInstance.foldLeft(self, b)(f)
+
+  def foldr[B](b: Eval[B])(f: (A, Eval[B]) => Eval[B]): Eval[B] = typeClassInstance.foldRight(self, b)(f)
+}
diff --git a/tests/src/test/scala/cats/tests/SyntaxTests.scala b/tests/src/test/scala/cats/tests/SyntaxTests.scala
@@ -86,10 +86,12 @@ class SyntaxTests extends AllInstances with AllSyntax {
     val b = mock[B]
     val f1 = mock[(B, A) => B]
     val b0: B = fa.foldLeft(b)(f1)
+    val b1: B = fa.foldl(b)(f1)
     val a0: A = fa.fold
 
     val f2 = mock[(A, Eval[B]) => Eval[B]]
     val lb0: Eval[B] = fa.foldRight(Now(b))(f2)
+    val lb1: Eval[B] = fa.foldr(Now(b))(f2)
 
     val fz = mock[F[Z]]
     val f3 = mock[Z => A]