Aaron Sherman writes: : Should a tied and/or lazy array be forced to present a length on demand, : or can length return undef on indeterminate arrays?
An array implementation can return anything it jolly well pleases, but I'd say undef would be a reasonable thing to return if the length is indeterminate. Then you can at least get warnings if you try to use the undefined value later. The class could even tag the undef with a property containing an unthrown exception that explains why the length is indeterminate, since Perl 6 will support interesting values of undef. Larry
