#528: Improve Tail Call Elimination -------------------------------------+-------------------------------------- Reporter: haruki.zaemon@… | Owner: lsansonetti@… Type: enhancement | Status: new Priority: minor | Milestone: Component: MacRuby | Keywords: tail call elimination optimisation tco -------------------------------------+-------------------------------------- As it currently stands, MacRuby performs TCO for a method that calls itself. This is a great start and the implementation appears to be better than any other current Ruby implementation. When dealing with OO data structures, it's more common to call methods on _other_ instances and/or mutual recursion between two methods--be they on the same or a different instance. For example, imagine traversing a linked list recursively: def each yield(head) tail.each(&block) end This works great for small-ish lists but when processing larger lists stack overflows are common place. To remedy this, it needs to be re- written iteratively: def each list = self while !list.empty? yield(list.head) list = list.tail end end Not only is the latter more verbose, but in either case, without TCO, because the code always executes in the context of the first element, the traversal must complete before the garbage collector has a chance to reap unreferenced elements. It would be great if MacRub could do tail-call elimination for any returning statement that no longer requires the stack. -- Ticket URL: <http://www.macruby.org/trac/ticket/528> MacRuby <http://macruby.org/>