Tuple2 complete, changed Foldable instances

Author: SandroMaglione

.packages

@@ -3,7 +3,7 @@
 # 
 # For more info see: https://dart.dev/go/dot-packages-deprecation
 # 
-# Generated by pub on 2021-06-13 21:30:13.314180.
+# Generated by pub on 2021-06-15 19:06:22.469619.
 _fe_analyzer_shared:file:///C:/Users/Sandro%20Maglione/AppData/Roaming/Pub/Cache/hosted/pub.dartlang.org/_fe_analyzer_shared-22.0.0/lib/
 analyzer:file:///C:/Users/Sandro%20Maglione/AppData/Roaming/Pub/Cache/hosted/pub.dartlang.org/analyzer-1.7.0/lib/
 args:file:///C:/Users/Sandro%20Maglione/AppData/Roaming/Pub/Cache/hosted/pub.dartlang.org/args-2.1.0/lib/

CHANGELOG.md

@@ -1,9 +1,13 @@
-# v0.0.4
+# v0.0.4 - 15 June 2021
 
-- Renamed `fold` method of `Foldable` to `foldLeft` [**BREAKING CHANGE**]
 - Completed `Unit` type documentation
 - Completed `Task` type implementation, documentation, and testing
 - Completed `TaskEither` type implementation, documentation, and testing
+- Completed implementation, documentation, and testing of `Foldable` instance on `Option` and `Either` [**BREAKING CHANGE**]
+- Completed `Tuple2` type implementation, documentation, and testing [**BREAKING CHANGE**]
+- Renamed `fold` method of `Foldable` to `foldLeft` [**BREAKING CHANGE**]
+- Updated methods API (`foldRight`, `foldLeft`, etc.) of `Foldable` instances (`Option`, `Either`, `Tuple`) [**BREAKING CHANGE**]
+- `IList` not longer working correctly (waiting for a [better solution for immutable collections](https://github.com/SandroMaglione/fpdart#roadmap)) [**BREAKING CHANGE**]
 
 # v0.0.3 - 13 June 2021
 

README.md

@@ -5,7 +5,7 @@
     <img src="https://img.shields.io/github/stars/SandroMaglione/fpdart?logo=github" />
   </a>
   <img src="https://img.shields.io/github/license/SandroMaglione/fpdart?logo=github" />
-  <img src="https://img.shields.io/badge/version-0.0.3-blue.svg" />
+  <img src="https://img.shields.io/badge/version-0.0.4-blue.svg" />
   <!-- <img src="https://img.shields.io/badge/flutter-v2.0.2-blue.svg" /> -->
   <img src="https://img.shields.io/badge/dart-v2.13.1-blue.svg" />
   <a href="https://github.com/SandroMaglione">
@@ -54,7 +54,7 @@ Fpdart is inspired by [fp-ts](https://gcanti.github.io/fp-ts/), [cats](https://t
 ```yaml
 # pubspec.yaml
 dependencies:
-  fpdart: ^0.0.3 # Check out the latest version
+  fpdart: ^0.0.4 # Check out the latest version
 ```
 
 ## Examples
@@ -204,10 +204,10 @@ The roadmap for types development is highlighted below (breaking changes to *'st
    - ~~Implementation~~
    - ~~Documentation~~
    - ~~Testing~~
-6. `Tuple`
-   - Implementation
-   - Documentation
-   - Testing
+6. ~~`Tuple`~~
+   - ~~Implementation~~
+   - ~~Documentation~~
+   - ~~Testing~~
 7. `State`
    - Implementation
    - Documentation
@@ -263,6 +263,7 @@ In general, any contribution or feedback is welcome (and encouraged!).
 
 ## Versioning
 
+- v0.0.4 - 15 June 2021
 - v0.0.3 - 13 June 2021
 - v0.0.2 - 13 June 2021
 - v0.0.1 - 28 May 2021

lib/src/either.dart

@@ -1,5 +1,6 @@
 import 'function.dart';
 import 'option.dart';
+import 'tuple.dart';
 import 'typeclass/typeclass.export.dart';
 
 /// Tag the [HKT2] interface for the actual [Either].
@@ -19,6 +20,58 @@ abstract class Either<L, R> extends HKT2<_EitherHKT, L, R>
         Extend2<_EitherHKT, L, R> {
   const Either();
 
+  /// Return the result of `f` called with `b` and the value of [Right].
+  /// If this [Either] is [Left], return `b`.
+  @override
+  C foldRight<C>(C b, C Function(C acc, R b) f);
+
+  /// Return the result of `f` called with `b` and the value of [Right].
+  /// If this [Either] is [Left], return `b`.
+  @override
+  C foldLeft<C>(C b, C Function(C acc, R b) f) =>
+      foldMap<Endo<C>>(dualEndoMonoid(), (b) => (C c) => f(c, b))(b);
+
+  /// Use `monoid` to combine the value of [Right] applied to `f`.
+  @override
+  C foldMap<C>(Monoid<C> monoid, C Function(R b) f) =>
+      foldRight(monoid.empty, (c, b) => monoid.combine(f(b), c));
+
+  /// Return the result of `f` called with `b` and the value of [Right].
+  /// If this [Either] is [Left], return `b`.
+  @override
+  C foldRightWithIndex<C>(C c, C Function(int i, C acc, R b) f) =>
+      foldRight<Tuple2<C, int>>(
+        Tuple2(c, length() - 1),
+        (t, b) => Tuple2(f(t.second, t.first, b), t.second - 1),
+      ).first;
+
+  /// Return the result of `f` called with `b` and the value of [Right].
+  /// If this [Either] is [Left], return `b`.
+  @override
+  C foldLeftWithIndex<C>(C c, C Function(int i, C acc, R b) f) =>
+      foldLeft<Tuple2<C, int>>(
+        Tuple2(c, 0),
+        (t, b) => Tuple2(f(t.second, t.first, b), t.second + 1),
+      ).first;
+
+  /// Returns `1` when [Either] is [Right], `0` otherwise.
+  @override
+  int length() => foldLeft(0, (b, _) => b + 1);
+
+  /// Return the result of `predicate` applied to the value of [Right].
+  /// If the [Either] is [Left], returns `false`.
+  @override
+  bool any(bool Function(R a) predicate) => foldMap(boolOrMonoid(), predicate);
+
+  /// Return the result of `predicate` applied to the value of [Right].
+  /// If the [Either] is [Left], returns `true`.
+  @override
+  bool all(bool Function(R a) predicate) => foldMap(boolAndMonoid(), predicate);
+
+  /// Use `monoid` to combine the value of [Right].
+  @override
+  R concatenate(Monoid<R> monoid) => foldMap(monoid, identity);
+
   /// If the [Either] is [Right], then change its value from type `R` to
   /// type `C` using function `f`.
   @override
@@ -216,7 +269,7 @@ class Right<L, R> extends Either<L, R> {
   Either<C, R> mapLeft<C>(C Function(L a) f) => Right<C, R>(_value);
 
   @override
-  C foldRight<C>(C b, C Function(R a, C b) f) => f(_value, b);
+  C foldRight<C>(C b, C Function(C acc, R a) f) => f(b, _value);
 
   @override
   C match<C>(C Function(L l) onLeft, C Function(R r) onRight) =>
@@ -292,7 +345,7 @@ class Left<L, R> extends Either<L, R> {
   Either<C, R> mapLeft<C>(C Function(L a) f) => Left<C, R>(f(_value));
 
   @override
-  C foldRight<C>(C b, C Function(R a, C b) f) => b;
+  C foldRight<C>(C b, C Function(C acc, R a) f) => b;
 
   @override
   C match<C>(C Function(L l) onLeft, C Function(R r) onRight) => onLeft(_value);

lib/src/ilist.dart

@@ -18,8 +18,8 @@ abstract class IList<T> extends HKT<IListHKT, T>
       concatMap((t) => a.map((f) => f(t)));
 
   @override
-  B foldRight<B>(B b, B Function(T a, B b) f) =>
-      reverse().foldLeft(b, (b, a) => f(a, b));
+  B foldRight<B>(B b, B Function(B acc, T a) f) =>
+      reverse().foldLeft(b, (b, t) => f(b, t));
 
   @override
   IList<B> flatMap<B>(covariant IList<B> Function(T a) f);
@@ -52,7 +52,7 @@ abstract class IList<T> extends HKT<IListHKT, T>
 
   /// Append an `IList<T>` to the list
   @override
-  IList<T> plus(covariant IList<T> l) => foldRight(l, (e, p) => Cons(e, p));
+  IList<T> plus(covariant IList<T> l) => foldRight(l, (e, p) => Cons(p, e));
 
   /// Apply `f` to the elements of this `IList` and `concat` the result.
   IList<B> concatMap<B>(IList<B> Function(T t) f) => IList.concat(map(f));

lib/src/option.dart

@@ -46,6 +46,70 @@ abstract class Option<A> extends HKT<_OptionHKT, A>
         Filterable<_OptionHKT, A> {
   const Option();
 
+  /// Return the result of `f` called with `b` and the value of [Some].
+  /// If this [Option] is [None], return `b`.
+  @override
+  B foldRight<B>(B b, B Function(B acc, A a) f);
+
+  /// Return the result of `f` called with `b` and the value of [Some].
+  /// If this [Option] is [None], return `b`.
+  @override
+  B foldLeft<B>(B b, B Function(B acc, A a) f) =>
+      foldMap<Endo<B>>(dualEndoMonoid(), (a) => (B b) => f(b, a))(b);
+
+  /// Use `monoid` to combine the value of [Some] applied to `f`.
+  @override
+  B foldMap<B>(Monoid<B> monoid, B Function(A a) f) =>
+      foldRight(monoid.empty, (b, a) => monoid.combine(f(a), b));
+
+  /// Return the result of `f` called with `b` and the value of [Some].
+  /// If this [Option] is [None], return `b`.
+  @override
+  B foldRightWithIndex<B>(B b, B Function(int i, B acc, A a) f) =>
+      foldRight<Tuple2<B, int>>(
+        Tuple2(b, length() - 1),
+        (t, a) => Tuple2(f(t.second, t.first, a), t.second - 1),
+      ).first;
+
+  /// Return the result of `f` called with `b` and the value of [Some].
+  /// If this [Option] is [None], return `b`.
+  @override
+  B foldLeftWithIndex<B>(B b, B Function(int i, B acc, A a) f) =>
+      foldLeft<Tuple2<B, int>>(
+        Tuple2(b, 0),
+        (t, a) => Tuple2(f(t.second, t.first, a), t.second + 1),
+      ).first;
+
+  /// Returns `1` when [Option] is [Some], `0` otherwise.
+  @override
+  int length() => foldLeft(0, (b, _) => b + 1);
+
+  /// Return the result of `predicate` applied to the value of [Some].
+  /// If the [Option] is [None], returns `false`.
+  @override
+  bool any(bool Function(A a) predicate) => foldMap(boolOrMonoid(), predicate);
+
+  /// Return the result of `predicate` applied to the value of [Some].
+  /// If the [Option] is [None], returns `true`.
+  @override
+  bool all(bool Function(A a) predicate) => foldMap(boolAndMonoid(), predicate);
+
+  /// Use `monoid` to combine the value of [Some].
+  @override
+  A concatenate(Monoid<A> monoid) => foldMap(monoid, identity);
+
+  /// Return the value of this [Option] if it is [Some], otherwise return `a`.
+  @override
+  Option<A> plus(covariant Option<A> a);
+
+  /// Return `Some(a)`.
+  @override
+  Option<A> prepend(A a) => Some(a);
+
+  /// If this [Option] is [None], return `Some(a)`. Otherwise return this [Some].
+  @override
+  Option<A> append(A a);
+
   /// Change the value of type `A` to a value of type `B` using function `f`.
   /// ```dart
   /// /// Change type `String` (`A`) to type `int` (`B`)
@@ -162,18 +226,6 @@ abstract class Option<A> extends HKT<_OptionHKT, A>
           E Function(A a, C c, D d) f) =>
       flatMap((a) => mc.flatMap((c) => md.map((d) => f(a, c, d))));
 
-  /// Return the value of this [Option] if it is [Some], otherwise return `a`.
-  @override
-  Option<A> plus(covariant Option<A> a);
-
-  /// Return `Some(a)`.
-  @override
-  Option<A> prepend(A a) => Some(a);
-
-  /// If this [Option] is [None], return `Some(a)`. Otherwise return this [Some].
-  @override
-  Option<A> append(A a);
-
   /// Execute `onSome` when value is [Some], otherwise execute `onNone`.
   B match<B>(B Function(A a) onSome, B Function() onNone);
 
@@ -323,7 +375,7 @@ class Some<A> extends Option<A> {
   Option<B> map<B>(B Function(A a) f) => Some(f(_value));
 
   @override
-  B foldRight<B>(B b, B Function(A a, B b) f) => f(_value, b);
+  B foldRight<B>(B b, B Function(B acc, A a) f) => f(b, _value);
 
   @override
   Option<B> flatMap<B>(covariant Option<B> Function(A a) f) => f(_value);
@@ -394,7 +446,7 @@ class None<A> extends Option<A> {
   Option<B> map<B>(B Function(A a) f) => Option.none();
 
   @override
-  B foldRight<B>(B b, B Function(A a, B b) f) => b;
+  B foldRight<B>(B b, B Function(B acc, A a) f) => b;
 
   @override
   Option<B> flatMap<B>(covariant Option<B> Function(A a) f) => Option.none();

lib/src/tuple.dart

@@ -58,12 +58,12 @@ class Tuple2<T1, T2> extends HKT2<_Tuple2HKT, T1, T2>
   ///
   /// Same as `foldLeft`.
   @override
-  C foldRight<C>(C b, C Function(T2 a, C b) f) => f(_value2, b);
+  C foldRight<C>(C b, C Function(C acc, T2 a) f) => f(b, _value2);
 
   /// Return value of type `C` by calling `f` with `b` and the first value of the [Tuple2].
   ///
   /// Same as `foldLeftFirst`.
-  C foldRightFirst<C>(C b, C Function(T1 a, C b) f) => f(_value1, b);
+  C foldRightFirst<C>(C b, C Function(C acc, T1 a) f) => f(b, _value1);
 
   /// Return value of type `C` by calling `f` with `b` and the second value of the [Tuple2].
   ///
@@ -81,40 +81,40 @@ class Tuple2<T1, T2> extends HKT2<_Tuple2HKT, T1, T2>
   /// Return value of type `C` by applying `f` on `monoid`.
   @override
   C foldMap<C>(Monoid<C> monoid, C Function(T2 a) f) =>
-      foldRight(monoid.empty, (a, b) => monoid.combine(f(a), b));
+      foldRight(monoid.empty, (c, b) => monoid.combine(c, f(b)));
 
   /// Return value of type `C` by applying `f` on `monoid`.
   C foldMapFirst<C>(Monoid<C> monoid, C Function(T1 a) f) =>
-      foldRightFirst(monoid.empty, (a, b) => monoid.combine(f(a), b));
+      foldRightFirst(monoid.empty, (c, t) => monoid.combine(f(t), c));
 
   /// Return value of type `C` by calling `f` with `b` and the second value of the [Tuple2].
   @override
-  C foldRightWithIndex<C>(C c, C Function(int i, T2 b, C c) f) =>
+  C foldRightWithIndex<C>(C c, C Function(int i, C acc, T2 b) f) =>
       foldRight<Tuple2<C, int>>(
         Tuple2(c, length() - 1),
-        (a, t) => Tuple2(f(t.second, a, t.first), t.second - 1),
+        (t, a) => Tuple2(f(t.second, t.first, a), t.second - 1),
       ).first;
 
   /// Return value of type `C` by calling `f` with `b` and the first value of the [Tuple2].
-  C foldRightFirstWithIndex<C>(C c, C Function(int i, T1 b, C c) f) =>
+  C foldRightFirstWithIndex<C>(C c, C Function(int i, C c, T1 b) f) =>
       foldRightFirst<Tuple2<C, int>>(
         Tuple2(c, length() - 1),
-        (a, t) => Tuple2(f(t.second, a, t.first), t.second - 1),
+        (t, a) => Tuple2(f(t.second, t.first, a), t.second - 1),
       ).first;
 
   /// Return value of type `C` by calling `f` with `b` and the second value of the [Tuple2].
   @override
-  C foldLeftWithIndex<C>(C c, C Function(int i, T2 b, C c) f) =>
+  C foldLeftWithIndex<C>(C c, C Function(int i, C acc, T2 b) f) =>
       foldLeft<Tuple2<C, int>>(
         Tuple2(c, 0),
-        (t, a) => Tuple2(f(t.second, a, t.first), t.second + 1),
+        (t, a) => Tuple2(f(t.second, t.first, a), t.second + 1),
       ).first;
 
   /// Return value of type `C` by calling `f` with `b` and the first value of the [Tuple2].
-  C foldLeftFirstWithIndex<C>(C c, C Function(int i, T1 b, C c) f) =>
+  C foldLeftFirstWithIndex<C>(C c, C Function(int i, C c, T1 b) f) =>
       foldLeftFirst<Tuple2<C, int>>(
         Tuple2(c, 0),
-        (t, a) => Tuple2(f(t.second, a, t.first), t.second + 1),
+        (t, a) => Tuple2(f(t.second, t.first, a), t.second + 1),
       ).first;
 
   /// Returns `1`.
@@ -131,6 +131,11 @@ class Tuple2<T1, T2> extends HKT2<_Tuple2HKT, T1, T2>
       foldMap(boolAndMonoid(), predicate);
 
   /// Combine the second value of [Tuple2] using `monoid`.
+  /// ```dart
+  /// const tuple = Tuple2('abc', 10);
+  /// final ap = tuple.concatenate(Monoid.instance(0, (a1, a2) => a1 + a2));
+  /// expect(ap, 10);
+  /// ```
   @override
   T2 concatenate(Monoid<T2> monoid) => foldMap(monoid, identity);