Michael Mehl, Christian Schulte, Gert Smolka
We propose a conservative extension of Oz that adds futures and by-need synchronization. Futures are read-only views of logic variables that make it possible to statically limit the scope in which a variable can be constrained. For instance, one can express with futures safe streams that cannot be assigned by their readers. By-need synchronization makes it possible to synchronize a thread on the event that a thread blocks on a future. It is used to express dynamic linking and lazy functions.