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.[*])
For optimization reasons track of a variable's "history" may be kept only upon explicit appearance of undo()... [*] To be definite, any atomic value-changing expression or statement, for a choice of "atomic" to be decided upon. Just my 2 cents, Michele -- : I've actually fixed the security glitches now Bullshit. Security is designed into a product. Your design is inherently insecure. This is not something you can fix by pecking in a few more lines of code. - Jay Tilton in clpmisc, "Re: free source for bbs"
