[REBOL] Re: bitset help
From: brett:codeconscious at: 28-Sep-2002 13:01
Hi Gregg, Romano,
> I ask myself if you learned all from that RT doc, i did not understand
> anything from it!
I'd heard that some DBs nowadays incorporate bit vector indexes - not sure
what the term is and after RT made those notes I figured it was time to find
out what bitset! could be used for. So I searched the internet for examples
and experimented with various series functions. So no, I didn't get it from
the docs :^)
> > On my machine and with this version a bitset seems to have a maximum
size of
> > 2040.
I need to correct this - after seeing your post.
I'm not sure what the maximum is now - could be as much as OS is willing to
provide perhaps.
For example this works, but I can here my disk starting to work heavily.
r: make bitset! 1024 * 1024 * 768
== make bitset! #{
0000000000000000000000000000000000000000000000000000000000000000
00000000000000000000000000000000000000000000000...
But 1024 * 1024 * 1024 causes a crash.
My comment about multiples of 8 could be wrong too, not sure what the actual
constraint is.
> >Here's a little function to represent the bits of a bitset:
> > stringbits: func [bitset [bitset!]][
> > enbase/base head reverse to-string load find/tail/last form bitset
{ }
> 2
> > ]
>
> Very useful. Cannot be removed that to-string?
Probably, it evolved :^)
> That reverse will not fail on different system? (big-endian/little endian)
Another good point. I'm using Win NT 4.0 on Intel. What happens on other
systems?
Thanks for the info on REMOVE as well.
Regards,
Brett.
