From: Hugh Sasse Staff Elec Eng <hgs@...>
Date: 2002-09-19T23:54:07+09:00
Subject: classes, constants, inheritance and ===

I have been looking at TupleSpaces and Rinda and so on.
I have been trying to figure out how I can have a task list for
workers of differing type.

I want to do something like

space.out(["task", Admin, ["type", letter1, letter2]])
space.out(["task", Manager, ["meet", board]])
space.out(["task", Manual, ["paint", lines, car_park]])
space.out(["task", Worker, ["attend", address, "CEO", date]])

where
   class Worker; end
   class Manager < Worker; end
   class Admin < Worker; end
   class Manual < Worker; end

And I don't want the manager to end up doing the painting, or the
manual staff to do the typing... but I'd like all workers to attend
the address by the CEO..

This means that I actually want to do the matching involved
backwards -- normally a template expresses which things I can pickup
from the tuplespace, and === gets the right things.  This way round
the tuple determines who can pick it up.

It seems there are >= 3 inforences here:
    I am using Linda techniques in a way which is inappropriate, and
        a better structure to the space exists
    I need to extend TupleSpace to allow this kind of matching,
        possibly using kind_of? instead of ===...
    I don't need to extend TupleSpace but because
        Worker === Worker is false, I need to fiddle with
        x.class.name.intern to get symbols I can manipulate, and
        figure out how to get back to a class from the symbol.

Has anyone else run into this before, and did they come up with a
good solution?  I still find it odd that Worker === Worker is false!

        Thank you,
        Hugh