fix: more iterator functions

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

iterator/stateless/compress.go

@@ -0,0 +1,27 @@
+// 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 (
+	G "github.com/IBM/fp-go/iterator/stateless/generic"
+	T "github.com/IBM/fp-go/tuple"
+)
+
+// Compress returns an [Iterator] that filters elements from a data [Iterator] returning only those that have a corresponding element in selector [Iterator] that evaluates to `true`.
+// Stops when either the data or selectors iterator has been exhausted.
+func Compress[U any](sel Iterator[bool]) func(Iterator[U]) Iterator[U] {
+	return G.Compress[Iterator[U], Iterator[bool], Iterator[T.Tuple2[U, bool]]](sel)
+}