Implement iterateWhile in terms of iterateWhileM

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
@@ -107,9 +97,9 @@ import simulacrum.typeclass
   def iterateWhileM[A](init: A)(f: A => F[A])(p: A => Boolean): F[A] =
     tailRecM(init) { a =>
       if (p(a))
-        map(f(a))(_.asLeft[A])
+        map(f(a))(Left(_))
       else
-        pure(a.asRight[A])
+        pure(Right(a))
     }
 
   /**