Re: collect-string (was: simple useful functions)

[Tak Ota <Takaaki.Ota@am.sony.com>]

The documentation can be something like this.  I just added the last
paragraph below.

-Tak

`M-x occur'
     Prompt for a regexp, and display a list showing each line in the
     buffer that contains a match for it.  To limit the search to part
     of the buffer, narrow to that part (*note Narrowing::).  A numeric
     argument N specifies that N lines of context are to be displayed
     before and after each matching line.  Currently, `occur' can not
     correctly handle multiline matches.

     The buffer `*Occur*' containing the output serves as a menu for
     finding the occurrences in their original context.  Click
     `Mouse-2' on an occurrence listed in `*Occur*', or position point
     there and type <RET>; this switches to the buffer that was
     searched and moves point to the original of the chosen occurrence.
     `o' and `C-o' display the match in another window; `C-o' does not
     select it.

     After using `M-x occur', you can use `next-error' to visit the
     occurrences found, one by one.  *note Compilation Mode::.

     When the numeric argument N is 0 or negative the buffer `*Occur*'
     collects all the matched strings.  When N is 0 the entire text
     matched is collected.  When N is negative the text in the -Nth
     parenthesized expression in the regexp is collected.


Thu, 04 Nov 2010 11:36:54 -0700: Tak Ota <Takaaki.Ota@am.sony.com> wrote:

> Thu, 4 Nov 2010 06:58:20 -0700: Stefan Monnier <monnier@iro.umontreal.ca> wrote:
> 
> > >> How about rename the command as collect-occur instead of
> > >> collect-string and document it as next?
> > > Wrong namespace.  IMO, the name should *start* with occur (but Stefan
> > > and Yidong are final authorities on that).
> > 
> > Agreed, namespace cleanliness is one of my favorite forms of
> > anal retentiveness.
> > 
> > The way I see it, the suggested collect-string is a variant of occur
> > where the result buffer contains none of the regexp matches's context.
> > So it would make sense to integrate it very tightly with `occur',
> > i.e. make M-x occur do the job of collect-strings for some particular
> > value of its argument NLINES.  Currently, NLINES is assumed to be
> > a number and all values of that number have a useful meaning, so we'd
> > have to add this new feature via a non-number value of NLINES.
> > 
> > E.g. C-u M-x occur could do the collect-string thingy (which is still an
> > incompatible change since some people may like to use C-u M-x occur to get
> > 4 lines of context, but you can make omelets without breaking eggs).
> > 
> > 
> >         Stefan
> > 
> 
> Now I am convinced.  How about the change below?  In conventional
> occur zero or negative value for nlines is meaningless correct?  We
> can use that for collection purpose.  i.e. C-u 0 M-x occur does the
> collection of the matching pattern.  C-u -1 M-x occur performs the
> collection of the recorded pattern 1.
> 
> -Tak
> 
> (defun occur-1 (regexp nlines bufs &optional buf-name)
>   (unless (and regexp (not (equal regexp "")))
>     (error "Occur doesn't work with the empty regexp"))
>   (unless buf-name
>     (setq buf-name "*Occur*"))
>   (let (occur-buf
> 	(active-bufs (delq nil (mapcar #'(lambda (buf)
> 					   (when (buffer-live-p buf) buf))
> 				       bufs))))
>     ;; Handle the case where one of the buffers we're searching is the
>     ;; output buffer.  Just rename it.
>     (when (member buf-name (mapcar 'buffer-name active-bufs))
>       (with-current-buffer (get-buffer buf-name)
> 	(rename-uniquely)))
> 
>     ;; Now find or create the output buffer.
>     ;; If we just renamed that buffer, we will make a new one here.
>     (setq occur-buf (get-buffer-create buf-name))
> 
>     (if (or (null (integerp nlines))
> 	    (> nlines 0))
> 	;; nlines is not zero or negative so perform nomal occur
> 	(with-current-buffer occur-buf
> 	  (occur-mode)
> 	  (let ((inhibit-read-only t)
> 		;; Don't generate undo entries for creation of the initial contents.
> 		(buffer-undo-list t))
> 	    (erase-buffer)
> 	    (let ((count (occur-engine
> 			  regexp active-bufs occur-buf
> 			  (or nlines list-matching-lines-default-context-lines)
> 			  (if (and case-fold-search search-upper-case)
> 			      (isearch-no-upper-case-p regexp t)
> 			    case-fold-search)
> 			  list-matching-lines-buffer-name-face
> 			  nil list-matching-lines-face
> 			  (not (eq occur-excluded-properties t)))))
> 	      (let* ((bufcount (length active-bufs))
> 		     (diff (- (length bufs) bufcount)))
> 		(message "Searched %d buffer%s%s; %s match%s for `%s'"
> 			 bufcount (if (= bufcount 1) "" "s")
> 			 (if (zerop diff) "" (format " (%d killed)" diff))
> 			 (if (zerop count) "no" (format "%d" count))
> 			 (if (= count 1) "" "es")
> 			 regexp))
> 	      (setq occur-revert-arguments (list regexp nlines bufs))
> 	      (if (= count 0)
> 		  (kill-buffer occur-buf)
> 		(display-buffer occur-buf)
> 		(setq next-error-last-buffer occur-buf)
> 		(setq buffer-read-only t)
> 		(set-buffer-modified-p nil)
> 		(run-hooks 'occur-hook)))))
>       ;; nlines is zero or negative integer perform collect-string
>       (with-current-buffer occur-buf
> 	(setq nlines (- nlines))
> 	(fundamental-mode)
> 	(let ((inhibit-read-only t)
> 	      (buffer-undo-list t))
> 	  (erase-buffer)
> 	  (while active-bufs
> 	    (with-current-buffer (car active-bufs)
> 	      (save-excursion
> 		(goto-char (point-min))
> 		(while (re-search-forward regexp nil t)
> 		  (let ((str (match-string nlines)))
> 		    (if str
> 			(with-current-buffer occur-buf
> 			  (insert str)
> 			  (or (zerop (current-column))
> 			      (insert "\n"))))))))
> 	    (setq active-bufs (cdr active-bufs))))
> 	(display-buffer occur-buf)))))