Michele Dondi wrote: > I must say I've still not read all apocalypses, and OTOH I suspect that > this could be done more or less easily with a custom function (provided > that variables will have a method to keep track of their history, or, more > reasonably, will be *allowed* to have it), but I wonder if Perl6 may > include a builtin undo() function to recover values prior, say, to the > last assignement (or push() or, etc. etc.[*])
Difficulties: define "history" of a function w.r.t. threads; closures; and system side-effects (writing to files, locking them etc.) In other words, if you want a transaction/rollback mechanism, use a suitable transaction library that fits your needs, not a half-baked kludge built into the base language.
