IndexSet apply mutation

Sources/Rearrange/IndexSet+ApplyMutation.swift

@@ -0,0 +1,27 @@
+import Foundation
+
+extension IndexSet {
+	public func apply(mutation: RangeMutation) -> IndexSet {
+		let ranges = nsRangeView.compactMap { $0.apply(mutation) }
+
+		return IndexSet(ranges: ranges)
+	}
+
+	public mutating func applying(mutation: RangeMutation) {
+		self = self.apply(mutation: mutation)
+	}
+
+	public func apply(mutations: [RangeMutation]) -> IndexSet {
+		var ranges = nsRangeView
+
+		for mutation in mutations {
+			ranges = ranges.compactMap { $0.apply(mutation) }
+		}
+
+		return IndexSet(ranges: ranges)
+	}
+
+	public mutating func applying(mutations: [RangeMutation]) {
+		self = self.apply(mutations: mutations)
+	}
+}