Merge pull request #1392 from zainab-ali/state

Adding get method to StateT
typelevel · Sep 22, 2016 · 7b15008 · 7b15008
2 parents c3fc69d + 9ce7dc0
commit 7b15008
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diff --git a/core/src/main/scala/cats/data/StateT.scala b/core/src/main/scala/cats/data/StateT.scala
@@ -151,6 +151,9 @@ object StateT extends StateTInstances {
   def modifyF[F[_], S](f: S => F[S])(implicit F: Applicative[F]): StateT[F, S, Unit] =
     StateT(s => F.map(f(s))(s => (s, ())))
 
+  def get[F[_], S](implicit F: Applicative[F]): StateT[F, S, S] =
+    StateT(s => F.pure((s, s)))
+
   def set[F[_], S](s: S)(implicit F: Applicative[F]): StateT[F, S, Unit] =
     StateT(_ => F.pure((s, ())))
 

diff --git a/tests/src/test/scala/cats/tests/StateTTests.scala b/tests/src/test/scala/cats/tests/StateTTests.scala
@@ -29,6 +29,14 @@ class StateTTests extends CatsSuite {
     }
   }
 
+  test("State.get and StateT.get are consistent") {
+    forAll{ (s: String) => 
+      val state: State[String, String] = State.get
+      val stateT: State[String, String] = StateT.get
+      state.run(s) should === (stateT.run(s))
+    }
+  }
+
   test("State.inspect and StateT.inspect are consistent") {
     forAll { (s: String, f: String => Int) =>
       val state: State[String, Int] = State.inspect(f)