feat: Added new 'MixedFraction.fromDouble' constructor

CHANGELOG.md

@@ -1,3 +1,7 @@
+## [4.1.2]
+ - Added the `MixedFraction.fromDouble` method
+ - Dependencies update
+
 ## [4.1.1]
  - Added more linter rules
  - Dependencies updates

example/CHANGELOG.md

@@ -1,4 +1,7 @@
-## 1.0.2
+## 1.0.4
+ - Updated dependencies
+
+## 1.0.3
  - Updated `analysis_options.yaml` file
  - Updated dependencies
 

example/pubspec.yaml

@@ -1,6 +1,6 @@
 name: fraction_example
 description: A simple Dart CLI application for the 'fraction' package
-version: 1.0.3
+version: 1.0.4
 repository: https://github.com/albertodev01/fraction/tree/master/example
 homepage: https://fluttercompletereference.com/
 publish_to: none
@@ -14,7 +14,7 @@ dependencies:
 
 dev_dependencies:
   # https://pub.dev/packages/dart_code_metrics
-  dart_code_metrics: ^4.15.2
+  dart_code_metrics: ^4.16.0
 
   # https://pub.dev/packages/test
-  test: ^1.21.1
+  test: ^1.21.4

lib/src/types/mixed.dart

@@ -150,6 +150,42 @@ class MixedFraction extends Rational {
     );
   }
 
+  /// Tries to give a fractional representation of a double according with the
+  /// given precision. This implementation takes inspiration from the
+  /// (continued fraction)[https://en.wikipedia.org/wiki/Continued_fraction]
+  /// algorithm.
+  ///
+  /// ```dart
+  /// MixedFraction.fromDouble(5.46) // represented as 5 + 23/50
+  /// ```
+  ///
+  /// Note that irrational numbers can **not** be represented as fractions, so
+  /// if you try to use this method on π (3.1415...) you won't get a valid
+  /// result.
+  ///
+  /// ```dart
+  /// MixedFraction.fromDouble(math.pi)
+  /// ```
+  ///
+  /// The above returns a mixed fraction because the algorithm considers only
+  /// the first 10 decimal digits (since `precision` is set to 1.0e-10).
+  ///
+  /// ```dart
+  /// MixedFraction.fromDouble(math.pi, precision: 1.0e-20)
+  /// ```
+  ///
+  /// This example will return another different value because it considers the
+  /// first 20 digits. It's still not a fractional representation of pi because
+  /// irrational numbers cannot be expressed as fractions.
+  ///
+  /// This method is good with rational numbers.
+  factory MixedFraction.fromDouble(double value, {double precision = 1.0e-12}) {
+    // Use 'Fraction' to reuse the continued fraction algorithm.
+    final fraction = Fraction.fromDouble(value, precision: precision);
+
+    return fraction.toMixedFraction();
+  }
+
   @override
   int get numerator => _numerator;
 

pubspec.yaml

@@ -1,6 +1,6 @@
 name: fraction
 description: A package that helps you working with mathematical fractions.
-version: 4.1.1
+version: 4.1.2
 repository: https://github.com/albertodev01/fraction
 homepage: https://fluttercompletereference.com/
 
@@ -9,7 +9,7 @@ environment:
 
 dev_dependencies:
   # https://pub.dev/packages/dart_code_metrics
-  dart_code_metrics: ^4.15.2
+  dart_code_metrics: ^4.16.0
 
   # https://pub.dev/packages/test
-  test: ^1.21.1
+  test: ^1.21.4

test/types/mixed_test.dart

@@ -125,6 +125,15 @@ void main() {
       expect(fraction3.numerator, equals(2));
       expect(fraction3.denominator, equals(7));
       expect(fraction3.toString(), equals('-6 2/7'));
+
+      expect(
+        MixedFraction(whole: -3, numerator: 2, denominator: 5).toFraction(),
+        equals(Fraction(-17, 5)),
+      );
+      expect(
+        MixedFraction(whole: -4, numerator: 5, denominator: 6).toFraction(),
+        equals(Fraction(-29, 6)),
+      );
     });
 
     test(
@@ -189,6 +198,31 @@ void main() {
         );
       },
     );
+
+    test(
+      'Making sure that mixed fractions are properly constructed from '
+      'decimal values',
+      () {
+        expect(
+          MixedFraction.fromDouble(5.46),
+          equals(
+            MixedFraction(whole: 5, numerator: 23, denominator: 50),
+          ),
+        );
+        expect(
+          MixedFraction.fromDouble(1.06),
+          equals(
+            MixedFraction(whole: 1, numerator: 3, denominator: 50),
+          ),
+        );
+        expect(
+          MixedFraction.fromDouble(0),
+          equals(
+            MixedFraction(whole: 0, numerator: 0, denominator: 1),
+          ),
+        );
+      },
+    );
   });
 
   group('Testing objects equality', () {