fromPredicate<A, B> function

Either<A, B> Function(B value) fromPredicate<A, B>(
  1. Predicate<B> predicate,
  2. A leftValue(
      )
    )

    A function that takes a predicate and a function that produces a leftValue. It returns a function that takes a value and returns an Either that is Right with the provided value if the predicate returns true for this value, and Left with the provided value if the predicate returns false.

    Example usage:

    var eitherFromPredicate = fromPredicate<String, int>((value) => value > 0, () => 'Negative value');
// returns a function

Either<String, int> either1 = eitherFromPredicate(42);  // This will be Right(42)
Either<String, int> either2 = eitherFromPredicate(-1);  // This will be Left('Negative value')

    @category lift

    Implementation

    Either<A, B> Function(B value) fromPredicate<A, B>(
        Predicate<B> predicate, A Function() leftValue) =>
    (B value) =>
        predicate(value) ? right<A, B>(value) : left<A, B>(leftValue());