public static IPromise <IPromiseEnumerator <T> > Intersect <T>(IPromiseEnumerator <T> left, IPromiseEnumerator <T> right, IEqualityComparer <T> comparer)
{
return(CountAlgorithm.Count(left).Then(leftCount => CountAlgorithm.Count(right).Then(rightCount =>
{
if (leftCount < rightCount)
{
return Tuple.Create(left, right);
}
return Tuple.Create(right, left);
})).Then(result =>
{
var x = result.Item1;
var y = result.Item2;
return ToSetAlgorithm.ToSet(x, comparer).Then(lookup => WhereEnumerator.Create(y, q => lookup.Contains(q, comparer)));
}));
}
public IPromise <IPromiseEnumerator <T> > MoveNext()
{
return(_items.MoveNext().Then(result =>
{
if (result == null)
{
return this.Factory.StartNew((IPromiseEnumerator <T>)null);
}
return _predicate(result.Current, _index).Then(take =>
{
IPromiseEnumerator <T> ret = new WhereEnumerator <T>(_index + 1, result, _predicate);
if (take)
{
return this.Factory.StartNew(ret);
}
return ret.MoveNext();
});
}));
}
public static IPromise <T> Last <T>(IPromiseEnumerator <T> items, Func <T, bool> predicate)
{
return(Last(WhereEnumerator.Create(items, predicate)));
}
public static IPromise <T> Single <T>(IPromiseEnumerator <T> items, Func <T, IPromise <bool> > predicate)
{
return(Single(WhereEnumerator.Create(items, predicate)));
}
public static IPromise <T> First <T>(IPromiseEnumerator <T> items, Func <T, int, IPromise <bool> > predicate)
{
return(First(WhereEnumerator.Create(items, predicate)));
}
public static IPromise <bool> Empty <T>(IPromiseEnumerator <T> items, Func <T, bool> predicate)
{
return(Empty(WhereEnumerator.Create(items, predicate)));
}
public static IPromise <IPromiseEnumerator <T> > Difference <T>(IPromiseEnumerator <T> left, IPromiseEnumerator <T> right, IEqualityComparer <T> comparer)
{
return(ToSetAlgorithm.ToSet(right, comparer).Then(lookup => WhereEnumerator.Create(left, q => !lookup.Contains(q, comparer))));
}
public PromiseGrouping(TKey key, IPromiseEnumerator <Tuple <TKey, TValue> > items, IEqualityComparer <TKey> comparer)
: base(items.Factory.Value(SelectEnumerator.Create(WhereEnumerator.Create(items, item => comparer.Equals(key, item.Item1)), item => item.Item2)))
{
this.Key = key;
}
public static IPromise <T> LastOrDefault <T>(IPromiseEnumerator <T> items, Func <T, int, IPromise <bool> > predicate)
{
return(LastOrDefault(WhereEnumerator.Create(items, predicate)));
}
public static IPromise <T> LastOrDefault <T>(IPromiseEnumerator <T> items, Func <T, bool> predicate, T defaultValue)
{
return(LastOrDefault(WhereEnumerator.Create(items, predicate), defaultValue));
}
public static IPromise <IPromiseEnumerator <Result> > GroupJoin <Inner, Outer, Key, Result>(
IPromiseEnumerator <Inner> inner, IPromiseEnumerator <Outer> outer,
Func <Inner, int, IPromise <Key> > innerKey, Func <Outer, int, IPromise <Key> > outerKey,
Func <Outer, IPromiseEnumerable <Inner>, IPromise <Result> > result,
IEqualityComparer <Key> comparer)
{
var innerKeys = SelectEnumerator.Create(inner, (x, i) => innerKey(x, i).Then(v => Tuple.Create(v, x)));
return(inner.Factory.Value(SelectEnumerator.Create(outer, (x, i) => outerKey(x, i).Then(
k => result(x, new PromiseEnumerable <Inner>(
inner.Factory.Value(SelectEnumerator.Create(WhereEnumerator.Create(innerKeys, y => comparer.Equals(y.Item1, k)), y => y.Item2))
))))));
}
public static IPromise <T> SingleOrDefault <T>(IPromiseEnumerator <T> items, Func <T, bool> predicate)
{
return(SingleOrDefault(WhereEnumerator.Create(items, predicate)));
}
public static IPromise <T> SingleOrDefault <T>(IPromiseEnumerator <T> items, Func <T, int, IPromise <bool> > predicate, T defaultValue)
{
return(SingleOrDefault(WhereEnumerator.Create(items, predicate), defaultValue));
}