OpenEuphoria

Re: Why equal(x[n], x[n..n])=0 ?

• Posted by Fernando Bauer <fmbauer at hotmai?.com> Sep 25, 2007
• 698 views

Hi Jason. Thanks for your reply.

Jason Gade wrote:
> 
> Sorry, I missed the second part of the post.
> 
> Fernando Bauer wrote:
> > 
> > Yes. The manual is also very clear about this. However, the meaning of my
> > question
> > is another:
> > Why does Euphoria (the manual) define slices like x[n..n] and x[n]
> > differently?
> > Why is an atom transformed in a sequence by using a slice?
> > 
> > An analogy:
> > Suppose you have a set of enumerated objects and the following rules:
> > a)You can hold only one at a time. (subscription)
> > b)If you need more objects you can use a container. (slicing)
> > Then, if someone asks you to collect the objects 2 to 4?
> >  - Because the number of objects is 3, you need to use the container (rule
> >  2).
> > Now, if someone asks you to collect the objects 2 to 2?
> >  - Because the number of objects is 1, you *don't* need to use the
> >  container,
> > you can catch it directly (rule 1). Besides, if you use the container
> > (sequence),
> > you will have to discard it to catch the object (an unnecessary procedure).
> > Regards,
> >    Fernando
> 
> Because when you say s[3..3] you are saying, "bring me one item in a bucket".
This is how slices are currently implemented in Euphoria, but it doesn't have to
be. Why do you need the bucket? Why don't you catch the item directly?

> It's not mutually exclusive. You can carry one thing with or without the
> bucket.
> You can always take the item out of the bucket after it is brought to you.
Yes, but taking the item out of the bucket consumes more time and energy!

> 
> Does that make sense?
Definitely yes.

> 
> --
> A complex system that works is invariably found to have evolved from a simple
> system that works.
> --John Gall's 15th law of Systemantics.
> 
> "Premature optimization is the root of all evil in programming."
> --C.A.R. Hoare
> 
> j.

Regards, 
   Fernando