fix: add samples for Any and Next to iterator package (#78)

Signed-off-by: Carsten Leue <carsten.leue@de.ibm.com>

iterator/stateless/example_test.go

@@ -0,0 +1,55 @@
+// Copyright (c) 2023 IBM Corp.
+// All rights reserved.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package stateless
+
+import (
+	"fmt"
+
+	A "github.com/IBM/fp-go/array"
+	F "github.com/IBM/fp-go/function"
+	O "github.com/IBM/fp-go/option"
+)
+
+func Example_any() {
+	// `Any` function that simply returns the boolean identity
+	anyBool := Any(F.Identity[bool])
+
+	fmt.Println(anyBool(FromArray(A.From(true, false, false))))
+	fmt.Println(anyBool(FromArray(A.From(false, false, false))))
+	fmt.Println(anyBool(Empty[bool]()))
+
+	// Output:
+	// true
+	// false
+	// false
+}
+
+func Example_next() {
+
+	seq := MakeBy(F.Identity[int])
+
+	first := seq()
+
+	value := F.Pipe1(
+		first,
+		O.Map(Current[int]),
+	)
+
+	fmt.Println(value)
+
+	// Output:
+	// Some[int](0)
+}