Lambda the Ultimate

In
this paper, we present a typeful approach to implementing objects that makes use of a recently introduced notion of guarded datatypes. In particular, we demonstrate how the feature of multiple inheritance can be supported with this approach, presenting a simple and general account for multiple inheritance in a typeful manner.

[snip]

We refer the reader to [XCC03,Xi02] for further details on this typeful approach to OOP (with single inheritance). The treatment of multiple inheritance in this paper bears a great deal of similarity to the treatment of single inheritance in [XCC03,Xi02], though there are also some substantial differences involved. In order to handle multiple inheritance, we are to treat a path from a (super) class to a (sub)class as a first-class value.

What languages do we wish were still maintained? My list starts:

• Charity
• Cayenne
• O'Haskell
• Kiev
• Cecil

Revisiting coroutines

This paper defends the revival of coroutines as a general control abstraction. After proposing a new classification of coroutines, we introduce the concept of full asymmetric coroutines and provide a precise definition for it through an operational semantics. We then demonstrate that full coroutines have an expressive power equivalent to one-shot continuations and one-shot partial continuations. We also show that full asymmetric coroutines and one-shot partial continuations have many similarities, and therefore present comparable benefits. Nevertheless, coroutines are easier implemented and understood, specially in the realm of procedural languages. Finally, we provide a collection of programming examples that illustrate the use of full asymmetric coroutines to support direct and concise implementation of several useful control behaviors, including cooperative multitasking.

Taking into account real or imaginary interest to control operators on LtU, I believe this paper makes nice reading. See also Coroutines in Lua.