[REBOL] Re: On mutability and sameness
From: gjones05:mail:orion at: 6-Jun-2001 10:13
From: "Joel Neely"
> Hi, again,
>
> Minor update to previous message...
>
> Ladislav Mecir wrote:
> >
> > I am pretty sure, that the feature you are describing is not a
> > bug. The reason for the behaviour is pretty simple. Rebol values
> > of type TUPLE! DATE! INTEGER! and some other types are immutable...
> >
>
> The oddity I described appears to reside in the /DATE "refinement"
> itself, based on this:
>
> >> a: now == 6-Jun-2001/9:05:53-5:00
> >> a/date == 6-Jun-2001
> >> a/date/date == 6-Jun-2001
> >> a/date/date/date/date/date/day == 6
>
> so that /DATE behaves less like a component selector and more like
> a function that takes a (complete) DATE! value and returns another
> DATE! value with the TIME! component set to none.
I think you are on to something with this hypothesis. I have expounded
on a concept from an earlier post. This gives more proof in the
pudding:
;First, the components of the full date time and zone
a/now ; == 6-Jun-2001/10:04:33-5:00
a/1 ; == 2001
a/2 ; == 6
a/3 ; == 6
a/4 ; == 10:04:33
a/4/1 ; == 10
a/4/2 ; == 4
a/4/3 ; == 33
a/5 ; == -5:00
;Now for just the "date" portion, notice the zone element (#5)?
a: now ; == 6-Jun-2001/10:04:33-5:00
a/date ; == 6-Jun-2001
a/date/1 ; == 2001
a/date/2 ; == 6
a/date/3 ; == 6
a/date/4 ; == none
a/date/5 ; == 0:00
--Scott Jones