On Fri, 5 Oct 2001, Mark J. Reed wrote:
> Well, "car" and "cdr" don't really fit; the key and value of a pair can be any
> type of object, unlike the Lisp case where the cdr is always a list
> (while the car can be either a list or an atom).
Incorrect - "cdr" can be anything at all, just like in Perl 6.
> But you can always define your own accessor methods with whatever
> names you like. :)
I can? How do I do that?
> What's an associative list, how does it differ from an associative array,
> and how is it wimpy?
An associative list is a list of pairs that's used like a hash but
requires a linear search for reads and writes. In Perl 5 it would look
like:
( [ foo => 1 ], [ bar => 2 ] )
Assoc lists are commonly used in LISPish languages that lack convenient
hashes. Emacs, for example, uses assoc lists extensively.
> Perl hashes *are* associative arrays;
Right. The difference between "array" and "list" when you start talking
about LISPy pairs is significant.
> we only started calling them "hashes" because it's shorter.
Well, that and it's less confusing. We have a hard enough time keeping
our arrays and lists separated without pulling in another data-structure.
-sam
