public static ITry <T> Where <T>(this ITry <T> value, Func <T, bool> evaluator, Func <Unit, Exception> error)
{
return(value.FlatMap(v => evaluator(v).ToTry(
t => v,
f => error(Unit.Value)
)));
}
public static ITry <T, INonEmptyEnumerable <E> > Where <T, E>(this ITry <T, INonEmptyEnumerable <E> > value, Func <T, bool> evaluator, Func <Unit, E> error)
{
return(value.FlatMap(v => evaluator(v).ToTry(
t => v,
f => error(Unit.Value).ToEnumerable()
)));
}
/// <summary>
/// If the successful result passes the predicate, returns the original try. Otherwise returns erroneous try with the specified result.
/// </summary>
public static ITry <A, E> Where <A, E>(this ITry <A, E> t, Func <A, bool> predicate, Func <Unit, E> otherwise)
{
return(t.FlatMap(a => predicate(a).Match(
_ => t,
_ => Try.Error <A, E>(otherwise(Unit.Value))
)));
}
/// <summary>
/// If the successful result passes the predicate, returns the original try. Otherwise returns erroneous try with the specified result.
/// </summary>
public static ITry <A, IEnumerable <E> > Where <A, E>(this ITry <A, IEnumerable <E> > t, Func <A, bool> predicate, Func <Unit, E> otherwise)
{
return(t.FlatMap(a => predicate(a).Match(
_ => t,
_ => Try.Error <A, IEnumerable <E> >(new[] { otherwise(Unit.Value) })
)));
}
private void HandlingNestedTriesWithFlatMap()
{
ITry <int, NetworkOperationError> number = Api.GetNumber();
ITry <ITry <int, NetworkOperationError>, NetworkOperationError> doubleNumber = number.Map(r => Api.DoubleNumber(r));
// This try succeeds only if both tries succeed. However the second lambda is only executed in case the first try is successful.
ITry <int, NetworkOperationError> doubleNumberFlattened = number.FlatMap(r => Api.DoubleNumber(r));
}
