Implementing stable sort

[sebastienros]

Fixes #808

[lahma]

Seems to hang?

[lahma]

If there's an overload of concrete type public ArrayOperationsIterator GetEnumerator() then there would be no dispatch overhead like the interfaces have, CLR will find the version by name.

[sebastienros]

What do you suggest? To implement it in each concrete type and call base.GetEnumerator() ?

[lahma]

I was referring to concrete enumerator method without interface, as seen here:

jint/Jint/Collections/DictionarySlim.cs

Lines 221 to 235 in 1d29ae7

	/// <summary>
	/// Gets an enumerator over the dictionary
	/// </summary>
	public Enumerator GetEnumerator() => new Enumerator(this); // avoid boxing
	/// <summary>
	/// Gets an enumerator over the dictionary
	/// </summary>
	IEnumerator<KeyValuePair<TKey, TValue>> IEnumerable<KeyValuePair<TKey, TValue>>.GetEnumerator() =>
	new Enumerator(this);
	/// <summary>
	/// Gets an enumerator over the dictionary
	/// </summary>
	IEnumerator IEnumerable.GetEnumerator() => new Enumerator(this);

Explicit interface implementations for generic use case and then one of concrete type to avoid boxing (struct via interface).

[sebastienros]

Updated but this new member is not called, and we need to user OrderBy for a stable sort.

[sebastienros]

There is a test that must be blocked in an infinite loop/ Haven't identified which one yet.

[sebastienros]

@lahma new review please

[lahma]

Looks good and contained. I think that at some point it would make sense to make the actual ObjectInstance and ArrayInstance implement the IEnumerable<JsValue>, this would open resolution for extension methods too.