On 16 December 2012 16:51, Stéphane Ducasse <stephane.ducasse@inria.fr> wrote:
Beware, Range exists in other languages (python, etc..). We should check if they correspond to a Smalltalk Interval or a mathematical Interval. If they correspond to a Smalltalk Interval, that will be one more un-necessary trap.
Note that we rarely use Interval, we just use #to: or #to:by:, so we could as well rename Interval->Range. And postpone creation of Mathematical Interval which is most likely unused in kernel image.
Why not? Now it would be good to move. but what I know is that igor wanted to have range intersection for the new text model. Another question: who thinks that ruby look at Smalltalk when they take a decision on their library? I do not think so. We can check what is around and **improve** our nice system
If you use Ruby for any length of time (and ignore most of the syntax) you will quickly realise that Ruby _is_ Smalltalk in many fundamental ways. It's just a pity Matz based its syntax on Perl (or so it seems). Ruby = Smalltalk with rubbish syntax and awesome integration with basic programmer tools and decent infrastructure. frank
Stef
2012/12/16 Stéphane Ducasse <stephane.ducasse@inria.fr>:
I agree so we should introduce Range. Did not you or camillo started to have Range? It can be a really nice class.
Stef On Dec 16, 2012, at 4:55 PM, Igor Stasenko wrote:
So, to my sense a behavior of Interval is overloaded.. it tries to be too many things at once: - be an interval in math sense (which is infinite set if used for Real numbers) - be a "collection" of numbers which you can enumerate (implies that it is finite).
to me, i would be much happier if we could have two different and non-intersecting entities:
- Enumeration. This one indeed can be used as a collection. i.e. "give me all integer numbers lying between values A and B, count each C-th number" Like that, (1 to: 1.5 by: 1) is enumeration which contains a single element. and #last should be = 1
- Interval (Range). A pure interval in math sense: defines a Set of numbers lying between numbers A and B, inclusive, where A <= B. Not enumerable, therefore no 'step' variable, instead what it could have, is flags to indicate whether interval endpoints included into interval or not.. i.e. (a,b) vs [a,b] vs [a,b) vs (a,b].
Not supporting enumeration (no #do: , no #add: no #at: etc). You can, however intersect, merge or diff two intervals etc.. same operations which you doing on sets (but that would require another entity - interval set). And of course, you can test whether some number lies within given interval or not.
The reason i started this topic is because some code were using 'range' for variables which holding intervals.. Now what you think is more appropriate protocol for something called 'range', this:
x := range first y := range last
or this:
x := range start y := range end
-- Best regards, Igor Stasenko.