Paul Rubin wrote: > Steven D'Aprano <[EMAIL PROTECTED]> writes: >>> Not tail calls, in general, no. >> Sorry, how does that work? You're suggesting that there is an algorithm >> which the compiler could follow to optimize away tail-recursion, but human >> beings can't follow the same algorithm? >> >> Now I'm confused. > > The usual compiler method is to translate the code into > continuation-passing style and thereby gain tail-recursion > optimization automagically.
There's no need to go into CPS just to optimise tail-recursion. After all, compilers were optimising tail-calls decades before Appel's work on SML/NJ. Converting tail-recursion to iteration is trivial, and perfectly reasonable for a human to do by hand. You add an outer "while True"-loop, the recursive call becomes a tuple assignment, and other code paths end with a break out of the loop. Completely mechanical and the resulting code doesn't even look that bad. Like Steven said, tail-call optimisation is not necessary as you can always hand-optimise it yourself. - Anders -- http://mail.python.org/mailman/listinfo/python-list
