From: Ted Zlatanov <tzz@lifelogs.com>
Subject: Re: bool-vector implementation in the Emacs core
Date: Fri, 23 Jan 2004 15:18:54 -0500 [thread overview]
Message-ID: <4nhdym4dw1.fsf@collins.bwh.harvard.edu> (raw)
In-Reply-To: m3k73jtt8b.fsf@kfs-l.imdomain.dk
On 23 Jan 2004, no-spam@cua.dk wrote:
> Ted Zlatanov <tzz@lifelogs.com> writes:
>
>>
>> We're talking about implementations of ranges in the Gnus developer
>> list right now, and our implementations of ranges is written in
>> Lisp. I can implement inversion lists in Lisp as well, but ranges
>> are such an essential Gnus piece that it seems like seeking core
>> support for them would be a good idea.
>
> What kind of C-level support are you looking for?
Something like a bool-vector, but internally implemented with an
inversion list. A double-linked C list of integers is perfect, so you
can insert and delete quickly. I can base it on the ELisp lists, I
was just hoping to make the bool-vector operations insanely fast :)
Now, there are two approaches - either provide an alternate internal
implementation of the bool-vector when you create it, or provide a
whole new data type. I'd rather be able to make a bool-vector with
an inversion list internally.
> If you implement inversion lists with lists, I don't really think
> lookups or inserts will be significantly faster in C than in
> byte-compiled Elisp.
You may be right, I'm not familiar with the differences. It seems to
me that a double-linked list in C that can only hold integers will be
significantly faster than the equivalent interpreted code using the
general-purpose ELisp lists.
> I do think that it would be a good idea to add the bool-vector
> support to the emacs lisp core files though, e.g. in subr.el.
>
> What kind of API do you envision?
Same as bool-vector: aref, aset. Also union, intersection, inversion,
etc. set operations would be nice. With inversion lists those
operations are very simple. Inversion, for instance - you just
precede the list with a 0, or delete the 0 if it's already there.
Thanks
Ted
next prev parent reply other threads:[~2004-01-23 20:18 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2004-01-21 16:52 bool-vector implementation in the Emacs core Ted Zlatanov
2004-01-21 17:06 ` Paul Jarc
2004-01-21 18:35 ` Ted Zlatanov
2004-01-23 0:16 ` Kim F. Storm
2004-01-23 0:37 ` Kenichi Handa
2004-01-23 2:19 ` Stefan Monnier
2004-01-23 20:26 ` Ted Zlatanov
2004-01-24 21:40 ` Richard Stallman
2004-01-25 2:59 ` Ted Zlatanov
2004-01-26 19:23 ` Richard Stallman
2004-01-27 1:32 ` Kim F. Storm
2004-01-23 20:18 ` Ted Zlatanov [this message]
2004-01-24 2:11 ` Kim F. Storm
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