Spans

// System.Spans — System.Core (decompiled from Larva HIR)

into namespace System
{
	/// What spans of comparable, equatable and number elements can do.
	public static class Spans
	{
		public:
			/// A span of a list's elements (in place: it sees them until the list grows).
			Of<T>(List<T> list) : Span<T> => new Span<T>(list.Items(), 0, list.Count);

			Sort<T : IComparable<T>>(Span<T> span)
			{
				if (span.Length > 1)
					Array.Sort(span.Items, span.Start, span.Length);
			}

			IndexOf<T : IHashable<T>>(Span<T> span, T value) : i32
			{
				loop (i32 i = 0..span.Length)
				{
					if (span[i].Equals(value))
						return i;
				}
				return -1;
			}

			Contains<T : IHashable<T>>(Span<T> span, T value) : bool => IndexOf(span, value) >= 0;

			SequenceEqual<T : IHashable<T>>(Span<T> a, Span<T> b) : bool
			{
				if (a.Length != b.Length)
					return false;
				loop (i32 i = 0..a.Length)
				{
					if (!a[i].Equals(b[i]))
						return false;
				}
				return true;
			}

			Sum<T : INumber<T>>(Span<T> span) : T
			{
				T total = T.Zero;
				T[] array = span.Items;
				loop (i32 i = span.Start..span.Start + span.Length)
					total = total + array[i];
				return total;
			}
	}
}