tailcalls 0.0.3

A library for trampolining tail calls by hand in cases when tail call optimization isn't done automatically. This library is ported from Scala's standard library (TailRec).

tailcall

A library for trampolining tail calls.

Example 1:

import 'package:tailcalls/tailcalls.dart';

TailRec<int> fib(int n) {
  if (n < 2) {
    return done(n);
  } else {
    return tailcall(() => fib(n - 1)).flatMap((x) {
      return tailcall(() => fib(n - 2)).map((y) {
        return (x + y);
      });
    });
  }
}

void main() {
  var res = fib(20).result();
  print("Result: $res");
}

Example 2:

TailRec<bool> isEven(List<int> xs) {
  if (xs.isEmpty) {
    return done(true);
  } else {
    return tailcall(() => isOdd(xs.sublist(1)));
  }
}

TailRec<bool> isOdd(List<int> xs) {
  if (xs.isEmpty) {
    return done(false);
  } else {
    return tailcall(() => isEven(xs.sublist(1)));
  }
}

void main() {
  List<int> r = rangeList(1, 40002);
  print(r.last);
  bool res = isEven(r).result();
  print(res);
}

Read more about trampoling in computing on Wikipedia.