> How about Bag, a set container? Alternately what we really want is > just a Hash where the type of the value is defined as 1, so it need > not be stored at all. Then most of the syntax for it just falls out > of Hash syntax, unless you like writing $x ∈ $bag instead of $bag{$x}. > Presumably we could make both work.
Please don't use bag as that is usually mathematically defined to be a multi-set that can contain multiple copies of any given element. In perl that would be a hash of Ints. I'm not sure that immutable make any sense as a concept separate from constant. A truly immutable object can't even be initialized, it has to be born ex-nilo already with a value. I think that only values (like 1, "ABC" and a set constant like (1|2|5|9)) are immutable. So, we should just stick with variable and constant (assigned once doesn't change afterwards) containers and not use the term immutable at all. -- [EMAIL PROTECTED] [EMAIL PROTECTED]