Hello everyone,

Attached is a re-implementation of the standard library module [Queue],
which I believe offers a few advantages over the standard one:

  + more space efficient (one memory block per element in the queue,
    instead of two), while equally fast;

  + the function [length] is tail recursive;

  + I have added an extra operation, [transfer], for my own convenience;
    it copies the contents of a queue to another queue in constant time.

Disclaimer: I haven't seriously tested this code. Comments are welcome.

-- 
François Pottier
Francois.Pottier@inria.fr
http://pauillac.inria.fr/~fpottier/