From 60d8e5af0c1c6b0677d2892869894a4b804be445 Mon Sep 17 00:00:00 2001
From: "David R. Bild" <david@davidbild.org>
Date: Wed, 9 Aug 2017 13:00:41 -0500
Subject: [PATCH] Implement iterateWhile in terms of iterateWhileM

---
 core/src/main/scala/cats/Monad.scala | 18 ++++--------------
 1 file changed, 4 insertions(+), 14 deletions(-)

diff --git a/core/src/main/scala/cats/Monad.scala b/core/src/main/scala/cats/Monad.scala
index f3f364a2a0..fa4d05079c 100644
--- a/core/src/main/scala/cats/Monad.scala
+++ b/core/src/main/scala/cats/Monad.scala
@@ -76,29 +76,19 @@ import simulacrum.typeclass
    * Execute an action repeatedly until its result fails to satisfy the given predicate
    * and return that result, discarding all others.
    */
-  def iterateWhile[A](f: F[A])(p: A => Boolean): F[A] = {
+  def iterateWhile[A](f: F[A])(p: A => Boolean): F[A] =
     flatMap(f) { i =>
-      tailRecM(i) { a =>
-        if (p(a))
-          map(f)(Left(_))
-        else pure(Right(a))
-      }
+      iterateWhileM(i)(_ => f)(p)
     }
-  }
 
   /**
    * Execute an action repeatedly until its result satisfies the given predicate
    * and return that result, discarding all others.
    */
-  def iterateUntil[A](f: F[A])(p: A => Boolean): F[A] = {
+  def iterateUntil[A](f: F[A])(p: A => Boolean): F[A] =
     flatMap(f) { i =>
-      tailRecM(i) { a =>
-        if (p(a))
-          pure(Right(a))
-        else map(f)(Left(_))
-      }
+      iterateUntilM(i)(_ => f)(p)
     }
-  }
 
   /**
     * Apply a monadic function iteratively until its result fails