Added Stream.isEmpty

nessos · Apr 21, 2015 · 86ce3f0 · 86ce3f0
1 parent ef35fc6
commit 86ce3f0
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diff --git a/src/Streams.Core/Streams.fs b/src/Streams.Core/Streams.fs
@@ -851,3 +851,12 @@ module Stream =
         match tryHead stream with
         | Some value -> value
         | None -> invalidArg "stream" "The stream was empty."
+
+
+    /// <summary>
+    ///     Returs true if the stream is empty and false otherwise.
+    /// </summary>
+    /// <param name="stream">The input stream.</param>
+    /// <returns>true if the input stream is empty, false otherwise</returns>
+    let inline isEmpty (stream : Stream<'T>) : bool =
+        stream |> exists (fun _ -> true) |> not
diff --git a/tests/Streams.Tests/StreamsTests.fs b/tests/Streams.Tests/StreamsTests.fs
@@ -411,3 +411,11 @@
                     with :? System.ArgumentException -> None
 
                 Assert.AreEqual(y, x)).QuickCheckThrowOnFailure()
+
+        [<Test>]
+        member __.``isEmpty``() =
+            Spec.ForAny<int []>(fun (xs : int  []) ->
+                let x = xs |> Stream.ofArray |> Stream.isEmpty
+                let y = xs |> Array.isEmpty
+
+                Assert.AreEqual(x, y)).QuickCheckThrowOnFailure()