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From: David Kastrup <dak@gnu.org>
Cc: Juri Linkov <juri@jurta.org>, dann@ics.uci.edu, emacs-devel@gnu.org
Subject: Re: should search ring contain duplicates?
Date: Thu, 04 May 2006 12:29:56 +0200	[thread overview]
Message-ID: <85iromw09n.fsf@lola.goethe.zz> (raw)
In-Reply-To: <m3slnqp08r.fsf@kfs-l.imdomain.dk> (Kim F. Storm's message of "Thu, 04 May 2006 12:12:20 +0200")

storm@cua.dk (Kim F. Storm) writes:

> storm@cua.dk (Kim F. Storm) writes:
>
>> I definitely think we need the history-push macro!
>> Here is something which works for me:
>
> .. almost :-)  Here is a better version:
>
> (defmacro history-push (newelt history &optional maxelt)
>   "Add NEWELT to the history list stored in the symbol HISTORY.
> If symbol MAXELT is specified, the maximum length of the history is
> specified by the value of that symbol.  Otherwise, the maximum history
> length is  to the value of the `history-length' property on symbol
> HISTORY, if set, or to the value of the `history-length' variable.
> Remove duplicates of NEWELT unless `history-delete-duplicates' is nil."
>   (declare (debug (form sexp)))
>   (unless maxelt
>     (setq maxelt `(or (get ',history 'history-length)
> 		       history-length)))
>   `(let ((len ,maxelt))
>      (if history-delete-duplicates
> 	 (setq ,history (delete ,newelt ,history)))
>      (setq ,history (cons ,newelt ,history))
>      (when (integerp len)
>        (if (= 0 len)
> 	   (setq ,history nil)
> 	 (if (> (length ,history) len)
> 	     (setcdr (nthcdr (1- len) ,history) nil))))))

What is the rationale for making this a macro?  It's not performance
relevant, and not short.  Seems like something

(defun history-push (newelt history &optional maxelt)
  "Add NEWELT to the history list stored in the symbol HISTORY.
If symbol MAXELT is specified, the maximum length of the history is
specified by the value of that symbol.  Otherwise, the maximum history
length is  to the value of the `history-length' property on symbol
HISTORY, if set, or to the value of the `history-length' variable.
Remove duplicates of NEWELT unless `history-delete-duplicates' is nil."
  (unless maxelt
    (setq maxelt (or (get history 'history-length)
		       history-length)))
  (if history-delete-duplicates
     (set history (delete newelt (symbol-value history))))
  (set history (cons newelt (symbol-value history)))
  (when (integerp maxelt)
      (if (= 0 maxelt)
	 (set history nil)
       (if (> (length (symbol-value history)) maxelt)
          (setcdr (nthcdr (1- maxelt) (symbol-value history)) nil)))))

Sure, you need to quote history in the call then, but it seems like
the trouble for a macro is not really warranted.

-- 
David Kastrup, Kriemhildstr. 15, 44793 Bochum

  reply	other threads:[~2006-05-04 10:29 UTC|newest]

Thread overview: 80+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2006-05-03  0:54 should search ring contain duplicates? Drew Adams
2006-05-03  7:27 ` Dan Nicolaescu
2006-05-03  8:26   ` Kim F. Storm
2006-05-03 12:48     ` Juri Linkov
2006-05-03 13:53       ` Kim F. Storm
2006-05-04 10:12         ` Kim F. Storm
2006-05-04 10:29           ` David Kastrup [this message]
2006-05-04 12:00             ` Stefan Monnier
2006-05-04 12:19             ` Kim F. Storm
2006-05-04 12:25               ` David Kastrup
2006-05-05 22:14               ` Richard Stallman
2006-05-05 23:55                 ` Kim F. Storm
2006-05-06  8:00                   ` Eli Zaretskii
2006-05-06 23:36                     ` Richard Stallman
2006-05-07 20:41                       ` Kim F. Storm
2006-05-04 16:05             ` Stuart D. Herring
2006-05-04 16:23               ` David Kastrup
2006-05-04 16:36                 ` Stuart D. Herring
2006-05-04 21:55               ` Kim F. Storm
2006-05-03 15:04       ` query-replace in isearch (was Re: should search ring contain duplicates?) Dan Nicolaescu
2006-05-03 20:27         ` query-replace in isearch Juri Linkov
2006-05-03 20:43         ` query-replace in isearch (was Re: should search ring contain duplicates?) Richard Stallman
2006-05-11  3:45         ` Richard Stallman
2006-05-11 11:57           ` Juri Linkov
2006-05-11 14:10             ` Kim F. Storm
2006-05-11 21:52               ` Juri Linkov
2006-05-19  3:05                 ` Juri Linkov
2006-05-20 22:39                   ` Kim F. Storm
2006-05-21  4:27                     ` Juri Linkov
2006-05-21  0:55                   ` Richard Stallman
2006-05-23  5:17                     ` Juri Linkov
2006-05-24  2:18                       ` Richard Stallman
2006-05-25 22:47                         ` Juri Linkov
2006-05-29  6:39                           ` Richard Stallman
2006-05-30  9:28                             ` Juri Linkov
2006-05-31  0:40                               ` Richard Stallman
2006-05-12  4:15             ` Richard Stallman
2006-05-12 11:14               ` Juri Linkov
2006-05-13  4:52                 ` Richard Stallman
2006-05-13 23:13                   ` Kim F. Storm
2006-05-14 15:09                     ` Richard Stallman
2006-05-14 20:52                       ` Kim F. Storm
2006-05-09 20:47       ` should search ring contain duplicates? Juri Linkov
2006-05-10  9:34         ` Kim F. Storm
2006-05-10 22:55           ` Juri Linkov
2006-05-11 10:08             ` Kim F. Storm
2006-05-14 23:29             ` Richard Stallman
2006-05-15  9:54               ` Kim F. Storm
2006-05-16  4:29                 ` Richard Stallman
2006-05-16 11:07                   ` Kim F. Storm
2006-05-11 11:59       ` C-f in isearch minibuffer (was: should search ring contain duplicates?) Juri Linkov
2006-05-11 14:04         ` C-f in isearch minibuffer Miles Bader
2006-05-11 21:52           ` Juri Linkov
2006-05-12  4:15         ` C-f in isearch minibuffer (was: should search ring contain duplicates?) Richard Stallman
2006-05-12 11:12           ` C-f in isearch minibuffer Juri Linkov
2006-05-13  4:52             ` Richard Stallman
2006-05-03 14:18   ` should search ring contain duplicates? Stefan Monnier
2006-05-03 14:25     ` Kim F. Storm
2006-05-03 14:40     ` Drew Adams
2006-05-03 15:54       ` Drew Adams
2006-05-03 20:27         ` Juri Linkov
2006-05-03 23:08           ` Drew Adams
2006-05-04 14:17         ` Richard Stallman
2006-05-04 15:07           ` Kim F. Storm
2006-05-04 22:44             ` Kim F. Storm
2006-05-05 19:05             ` Richard Stallman
2006-05-05 19:14               ` Drew Adams
2006-05-05 19:25                 ` David Kastrup
2006-05-05 20:09                   ` Drew Adams
2006-05-06 14:25                   ` Richard Stallman
2006-05-05 23:22                 ` Juri Linkov
2006-05-05 23:32                   ` Kim F. Storm
2006-05-06  2:05                   ` Drew Adams
2006-05-03 14:43     ` Dan Nicolaescu
2006-05-04 19:41     ` Richard Stallman
2006-05-03 20:42   ` Richard Stallman
2006-05-03 22:41     ` Dan Nicolaescu
2006-05-04 19:41       ` Richard Stallman
  -- strict thread matches above, loose matches on Subject: below --
2006-05-14 23:29 Richard Stallman
2006-05-14 23:46 ` Drew Adams

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