feat: Add powerset function and PowersetOnIterableExtension.

lib/src/_index.g.dart

@@ -1,13 +1,12 @@
 //.title
 // ▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓
 //
-// GENERATED BY DF GEN - DO NOT MODIFY BY HAND
+// GENERATED - DO NOT MODIFY BY HAND
 // See: https://github.com/robmllze/df_gen
 //
 // ▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓
 //.title~
 
-// --- PUBLIC FILES ---
 export 'unique_entries.dart';
 export 'merge.dart';
 export 'maybe_add_to.dart';
@@ -28,10 +27,5 @@ export 'extensions/traverse_map_on_map_extension.dart';
 export 'extensions/generic_type_extension.dart';
 export 'extensions/second_to_ninth_element_on_iterable_extension.dart';
 export 'extensions/non_nulls_on_map_extension.dart';
-export 'extensions/map_filter_extension.dart';
-
-// --- PRIVATE FILES (EXCLUDED) ---
-// export '_index.g.dart';
-
-// --- GENERATED FILES (EXCLUDED) ---
-// export '_index.g.dart';
+export 'extensions/powerset_on_iterable_extension.dart';
+export 'extensions/map_filter_extension.dart';

lib/src/extensions/powerset_on_iterable_extension.dart

@@ -0,0 +1,69 @@
+//.title
+// ▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓
+//
+// Dart/Flutter (DF) Packages by DevCetra.com & contributors. The use of this
+// source code is governed by an MIT-style license described in the LICENSE
+// file located in this project's root directory.
+//
+// See: https://opensource.org/license/mit
+//
+// ▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓
+//.title~
+
+extension PowersetOnIterableExtension<T> on Iterable<T> {
+  /// Returns the powerset using the provided [combinator].
+  ///
+  /// The powerset of a set is the set of all possible subsets of the set.
+  ///
+  /// The [combinator] is a function that combines two elements of the set.
+  ///
+  /// For example, given the set {1, 2, 3} and the combinator `+`, the powerset
+  /// would be {1, 2, 3, 1+2, 1+3, 2+3, 1+2+3}.
+  Iterable<T> powerset(T Function(T a, T b) combinator) {
+    return _powerset(
+      map((e) => {e}).toList(),
+      combinator,
+    );
+  }
+}
+
+final _powerset = powerset;
+
+/// Returns the powerset of the given [source] using the provided [combinator].
+///
+/// The powerset of a set is the set of all possible subsets of the set.
+///
+/// The [combinator] is a function that combines two elements of the set.
+///
+/// For example, given the set {1, 2, 3} and the combinator `+`, the powerset
+/// would be {1, 2, 3, 1+2, 1+3, 2+3, 1+2+3}.
+Iterable<T> powerset<T>(
+  Iterable<Iterable<T>> source,
+  T Function(T a, T b) combinator,
+) {
+  // Filter out empty sets to simplify logic
+  final input = source.where((e) => e.isNotEmpty).toList();
+
+  if (input.isEmpty) {
+    return {};
+  } else if (input.length == 1) {
+    return input[0];
+  } else {
+    // Combine the first two sets using the provided combinator
+    final combined = <T>{};
+    for (final a in input[0]) {
+      for (final b in input[1]) {
+        combined.add(combinator(a, b));
+      }
+    }
+
+    // Recursively process the remaining sets
+    return powerset(
+      [
+        combined,
+        ...input.skip(2),
+      ],
+      combinator,
+    );
+  }
+}

pubspec.yaml

@@ -12,7 +12,7 @@
 
 name: df_collection
 description: A package designed to extend Dart collections by offering additional functionality.
-version: 0.6.1
+version: 0.6.2
 repository: https://github.com/robmllze/df_collection
 funding:
   - https://www.buymeacoffee.com/robmllze