Some thought's about the Interval discussion:

Squeak and Smalltalk in general mixes mathematical 
intervals and numerical orders in the Interval class:

If we use

(1 to: 20)   we expect to get an interval with a beginning and
             an end. We can ask this interval if it includes
             a number. It should return true if this number is
		 inside the interval. 
		 Example: 
			(1 to: 20) includes: 0.9  -> false	
			(1 to: 20) includes: 1    -> true

			(1 to: 20) includes: 1.1  -> true	
		 The interval by itself is continuous. [----]
             Maybe we should also think about open intervals with
             infinite beginning or end. [--[
			(1 to: oo) includes: 100 factorial -> true
 		 oo stands for infinite sign.

(1 to: 20 by: 3) means we want to have a collection of numbers 
		     like the following: (1,4,7,...,19).
                 The method Integer>>to:by: should therefore
                 return an array, an instance of a new class
                 called NumericalOrder or whatever. As mathematician 
		     we would'nt expect an interval as return value, would
we.

As Smalltalker we would expect an Interval, because we know of
the Integer>>to:by: implementation.

I've asked some non-smalltalkers about that with the result that
people wouldn't expect an interval, because an interval has only a
beginning and an end and is continuous. (They also expect the 
result of 3+4*7 as 31 ;)

The only reason for returning an interval is that Smalltalk
can safe a lot of memory if it stores only the beginning, the end and
an increment. So you can easily iterate through a huge collection of
numbers. 
(1 to: 4000 by: 3) do: [...] 


-Torsten