Functional

Utilities for functional programimng in dart.

Install

Add this in dependencies of pubspec.yaml

functional: ^0.9.4+1

Import

import 'package:functional/functional.dart';

Usage

Currying

int add(int a, int b) => a + b;

void main() {
  final inc = add % 1;
  final dec = add % -1;

  print(inc(5)); // Same as add(1, 5);
  print(dec(5)); // Same as add(-1, 5);
}

Currying For Optional Parameters

void printAll({String a, int b, double c}) {
  print(a);
  print(b);
  print(c);
}

void main() {
  final func = printAll % #a['Hello'] % #b[2] % #c[4.0];
  func(); // Same as printAll(a: 'Hello', b: 2, c: 4.0);
}

Function Piping

String toUpperCase(String s) => s.toUpperCase();

void main() {
  final convertToUppercaseAndPrint = toUpperCase | print;
  convertToUppercaseAndPrint('Hello'); 
    // Same as print(toUpperCase('Hello'));
}

Collection Piping

int inc(int a) => a++;

void main() {
    
  [1, 2, 3, 4, 5, 6] | print;
  // Same as [1, 2, 3, 4, 5, 6].forEach((int value) => print(value));

  final incrementedList = [1, 2, 3, 4, 5, 6] ^ inc;
  // Same as [1, 2, 3, 4, 5, 6].map((int value)=> inc(value));

  print(incrementedList);
  // Will print : (2, 3, 4, 5, 6, 7)

  incrementedList | print;
  /* Will print : 
     2
     3
     4
     5
     6
     7
  */
}

Stream Piping

Stream<int> generate(int start, int end, Duration duration) async* {
  for (int i = start; i <= end; i++) {
    yield i;
    await Future.delayed(duration);
  }
}

void main() {
    
  final stream = generate(1, 9, Duration(seconds: 1));
  final subscription = stream | print;
  // Same as stream.listen((event) => print(event));

}