From: "Satyaki Das" <satyakid@stanford.edu>
Cc: monnier+gnu/emacs@rum.cs.yale.edu
Subject: Re: request for a new function, say, `sequence'
Date: Tue, 25 Mar 2003 17:44:02 -0800 [thread overview]
Message-ID: <31827.1048643042@theforce.Stanford.EDU> (raw)
In-Reply-To: <200303260018.JAA08092@etlken.m17n.org>
Kenichi Handa <handa@m17n.org> writes:
> In your example code, you united the implementaion of range
> and usage of the returned list. In such a way, of course,
> it is natural that we can make a function that uses `range'
> more concise and efficient.
This should be done only if it doesn't affect the readability and
simplicity of the code.
> > Do you have a counter-example to this?
>
> How about the code something like this.
>
> (defvar dev-consonants
> (append (range (decode-char 'ucs #x0915) (decode-char 'ucs #x0939))
> (range (decode-char 'ucs #x0958) (decode-char 'ucs #x095F))))
>
> (defun dev-looking-at-syllable ()
> (and (memq (following-char) dev-consonants)
> (looking-at dev-syllable-pattern)))
>
> The first `memq' is to avoid the heavy `looking-at' in an
> unnecessary case.
This seems like a reasonable usage scenario for `range'. However
since you are doing this for efficiency reasons, isn't it more
efficient to compare with <= than to use memq to to compare it
with 45 separate integers?
> The defvar part can be written as:
>
> (defvar dev-consonants
> (append (loop for x from (decode-char 'ucs #x0915) to (decode-char 'ucs #x0939)
> collect x)
> (loop for x from (decode-char 'ucs #x0958) to (decode-char 'ucs #x095F)
> collect x)))
Or you could do it in one loop and collect with a when. But I
agree that this could easily get quite hairy if there are lots of
ranges to consider.
> but using `range' is much more handy and easier to read.
Agreed.
> > IMO, a new builtin function is needed if and only if it makes
> > writing code easier or makes it simpler.
>
> I'm not requesting a builtin function.
Sorry about the bad terminology. I meant a library function.
> And, `range' surely
> makes writing code easier and makes the code simpler as well
> as dolist, dotimes, while, and etc. do.
Agreed. But I would be careful in its use, since it can
potentially cons a lot (if used inside of a loop for instance).
> > So I suggest that a more descriptive name be chosen -- for
> > instance something like `make-sequence-of-numbers'.
>
> I don't insist on having TYPE argument, always returning a
> list is ok. So, for instance, make-number-list, is also
> acceptable.
Yes, this seems reasonable if you don't want the vectors and
string types.
Satyaki
next prev parent reply other threads:[~2003-03-26 1:44 UTC|newest]
Thread overview: 49+ messages / expand[flat|nested] mbox.gz Atom feed top
2003-03-23 3:02 request for a new function, say, `sequence' Kenichi Handa
2003-03-24 15:41 ` Stefan Monnier
2003-03-25 0:15 ` Kenichi Handa
2003-03-25 0:50 ` Kenichi Handa
2003-03-25 0:57 ` Stefan Monnier
2003-03-25 1:25 ` Kenichi Handa
2003-03-25 1:47 ` Luc Teirlinck
2003-03-25 1:51 ` Luc Teirlinck
2003-03-25 1:59 ` Kenichi Handa
2003-03-25 2:29 ` Luc Teirlinck
2003-03-25 1:57 ` Satyaki Das
2003-03-25 2:08 ` Kenichi Handa
2003-03-25 2:41 ` Satyaki Das
2003-03-25 4:46 ` Kenichi Handa
2003-03-25 5:05 ` Satyaki Das
2003-03-25 5:40 ` Kenichi Handa
2003-03-25 20:10 ` Satyaki Das
2003-03-26 0:18 ` Kenichi Handa
2003-03-26 1:44 ` Satyaki Das [this message]
2003-03-26 2:38 ` Luc Teirlinck
2003-03-26 7:31 ` Edward O'Connor
2003-03-26 8:48 ` Thien-Thi Nguyen
2003-03-26 12:18 ` Kenichi Handa
2003-03-27 3:30 ` Richard Stallman
2003-04-03 2:54 ` Kenichi Handa
2003-04-03 3:44 ` Miles Bader
2003-04-03 22:52 ` Richard Stallman
2003-04-03 10:41 ` Thien-Thi Nguyen
2003-04-04 2:11 ` Vinicius Jose Latorre
2003-04-04 22:23 ` Richard Stallman
2003-04-05 2:10 ` Vinicius Jose Latorre
2003-04-06 2:00 ` Richard Stallman
2003-04-08 8:10 ` Kenichi Handa
2003-04-03 22:52 ` Richard Stallman
2003-03-25 15:27 ` Stefan Monnier
2003-03-25 23:11 ` Kenichi Handa
2003-03-26 0:11 ` Miles Bader
2003-03-26 0:40 ` Luc Teirlinck
2003-03-26 1:34 ` Miles Bader
2003-03-26 0:54 ` Kenichi Handa
2003-03-26 1:29 ` Miles Bader
2003-03-26 15:44 ` Stefan Monnier
2003-03-27 0:09 ` Luc Teirlinck
2003-03-27 15:20 ` Stefan Monnier
2003-03-27 15:53 ` Luc Teirlinck
2003-03-27 16:06 ` Stefan Monnier
2003-03-27 17:03 ` Luc Teirlinck
2003-03-27 17:08 ` Stefan Monnier
2003-03-26 2:41 ` Richard Stallman
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