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[REBOL] Re: Temporal data [was is REBOL OO]

From: SunandaDH:aol at: 14-Jan-2004 17:15

Hi Gregg!
> Sac> 256 bits isn't enough for a bit-per-day for a whole year. We need > Sac> two bitmaps. > > You can do it with one.
Amazing, thanks. I think I'd got myself blindsided about the maximum length of a bitset because of the length of a charset charset. I should have remembered that Carl is subtler than most of my assumptions. Incidentally, I thought I was about to find a bug in your code, or in the way bits are inserted in bitsets. Consider this: mybitset: make bitset 128 insert mybitset 7 insert mybitset 8 mold mybitset "make bitset! #{80010000000000000000000000000000}" Look at that: those two bits are nowhere near adjacent. But: available? mybitset 2 == 8 Correct answer! Must be an endian issue in the way bitsets are displayed. Bits in an octet are numbered left to right (from 0 to 7, natch) but displayed right to left, thus creating an optical illusion that bits 0 and 15 are adjacent:
>> mybitset: make bitset 16
== make bitset! #{0000}
>> insert mybitset 0
== make bitset! #{0100}
>> insert mybitset 15
== make bitset! #{0180} Just another of those REBOL gotchas. Sunanda.