updating buffer window while accepting minibuffer input

updating buffer window while accepting minibuffer input

[Buchs, Kevin J.]

This is a follow-up to "regexp nirvana - near miss" (thanks Drew for 
giving me this programming burden ;-). I'm wanting to traverse a list of 
buffer positions according to minibuffer keystrokes and have the 
referenced buffer position update (and eventually highlight) much like 
isearch-*. I'm stuck on the buffer position not actually updating 
whilest I am in the midst of (read-minibuffer-input). I have spent about 
two hours delving into how isearch works and came out without a clue as 
to how it actually gets minibuffer reading activated. So, I'm seeking 
help. Code follows signature.

Kevin Buchs   Research Computer Services   Phone: 507-538-5459
Mayo Clinic   200 1st. St SW   Rochester, MN 55905
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(defun regexpneg-fwd ()
    (interactive)
      ;; Move to next match
      (if (< regexpneg-pointer (1- (length regexpneg-list)))
             (progn
                  (set-buffer regexpneg-buffer)
                  (setq regexpneg-pointer (1+ regexpneg-pointer))
                  (goto-char (nth regexpneg-pointer regexpneg-list))
                  (recenter 5)
                  (message "buffer: %S, position: %d, pointer: %d"
                         (current-buffer) (point) regexpneg-pointer))))


(defun regexpneg-rev ()
    (interactive)
      ;; Move to prior match
      (unless (= regexpneg-pointer 0)
             (set-buffer regexpneg-buffer)
             (setq regexpneg-pointer (1- regexpneg-pointer))
             (goto-char (nth regexpneg-pointer regexpneg-list))
             (recenter 5)
             (message "buffer: %S, position: %d, pointer: %d"
                  (current-buffer) (point) regexpneg-pointer)))


(defun regexpneg (part negpart)
      "Search for regexp part, not followed by regexp negpart; You can 
advance in search hits with C-s or SPACE. Reverse with C-r or DEL"
      (interactive)
      (let (
                      (point-start (point))
                      (subsetnotlist '()))

             ;; Save a reference to current buffer
             (setq regexpneg-buffer (current-buffer))

             ;; Search for 'part' - return list of locations = 
regexpneg-list
             (setq regexpneg-list '())
             (while (re-search-forward part nil t)
                  (setq regexpneg-list (append regexpneg-list
  (list (match-beginning 0)))))

             ;; Search for 'part'+'negpart' - return list of locations = 
subsetnotlist
             (goto-char point-start)
             (while (re-search-forward (concat part negpart) nil t)
                  (setq subsetnotlist (append subsetnotlist (list 
(match-beginning 0)))))

             ;; Delete members of subsetnotlist from regexpneg-list
             (dolist (var subsetnotlist)
                  (delq var regexpneg-list))

             ;; Check for keymap or create it
             (unless (keymapp 'regexpneg-keymap)
                  (setq regexpneg-keymap (make-sparse-keymap))
                  (define-key regexpneg-keymap "\C-s" 'regexpneg-fwd)
                  (define-key regexpneg-keymap " " 'regexpneg-fwd)
                  (define-key regexpneg-keymap "\C-r" 'regexpneg-rev)
                  (define-key regexpneg-keymap "DEL" 'regexpneg-rev)
                  (define-key regexpneg-keymap "\C-j" 'exit-minibuffer)
                  (define-key regexpneg-keymap "\C-m" 'exit-minibuffer))

             ;; Set index-pointer
             (setq regexpneg-pointer 0)

             ;; Move to first match
             (goto-char (nth regexpneg-pointer regexpneg-list))
             (message "buffer: %S, position: %d, pointer: %d"
                  (current-buffer) (point) regexpneg-pointer)

             ;; Show minibuffer for further options
             (setq resp (read-from-minibuffer
                  "REN: fwd=C-s,SPACE; rev=C-r,DEL; exit=C-j,C-m: " nil
                  regexpneg-keymap))
             (message "got response '%s'" resp)))

RE: updating buffer window while accepting minibuffer input

[Drew Adams]

> I'm wanting to traverse a list of
> buffer positions according to minibuffer keystrokes and have the
> referenced buffer position update (and eventually highlight) much like
> isearch-*. I'm stuck on the buffer position not actually updating
> whilest I am in the midst of (read-minibuffer-input). I have spent about
> two hours delving into how isearch works and came out without a clue as
> to how it actually gets minibuffer reading activated. 

The Isearch code is a bit complicated.  If you follow its model then you
will likely need to do many of the state-maintenance etc. things it does,
which are not necessarily directly related to searching.

Of particular note: Isearch does not really use the minibuffer (except
for odd jobs like when you use `M-e' to edit the search string).

Instead, it handles events in the usual way that Emacs does.  (In Emacs,
every key you hit corresponds to a command, which is then invoked.)

In Isearch, certain input events correspond to keys that are bound to
particular Isearch actions.  Other keys, such as `a', `B', `9', and `$'
have, as their corresponding action, to add the corresponding printable
character (`a', `B', `9', `$' etc.) to the search string.  Search then
begins again automatically (resumes), using the newly updated search string.
See `isearch-printing-char' for the treatment of printable chars.

In sum, the minibuffer is not involved at all, for reading your input.
In particular, you do *not* want to use `read-input-from-minibuffer',
if you want Isearch-like behavior.

(FWIW, I'm no expert on Isearch.  HTH.  Juri Linkov is one of the best
placed to answer questions about its code.)

Re: updating buffer window while accepting minibuffer input

[Michael Heerdegen]

"Buchs, Kevin J." <buchs.kevin@mayo.edu> writes:

> This is a follow-up to "regexp nirvana - near miss" (thanks Drew for
> giving me this programming burden ;-).

BTW, what nobody said yet is that both Icicles and Helm implement buffer
searches that allow negation, i.e., have built in what you described in
your prior post.  Before you reinvent the wheel ... maybe you find one
of these sufficient.

In Icicles' search, use the normal candidate exclusion mechanism.

In helm, use helm-occur and enter e.g. "rx1 !rx1rx2" to match lines that
match regexp rx1, but that do not match regexp rx1 followed by regexp
rx2  ("!" just means "negation").


Michael.

RE: updating buffer window while accepting minibuffer input

[Drew Adams]

> In Icicles' search, use the normal candidate exclusion mechanism.

Which means:

1. Type a pattern to match whatever subset of the current
   set of candidates you want to remove (exclude, subtract).

2. Then use `C-~' to remove them.

See "Chip Away the Non-Elephant" in the Icicles doc:
http://www.emacswiki.org//Icicles_-_Nutshell_View#ChippingAway

Re: updating buffer window while accepting minibuffer input

[Michael Heerdegen]

Drew Adams <drew.adams@oracle.com> writes:

> > In Icicles' search, use the normal candidate exclusion mechanism.
>
> Which means:
>
> 1. Type a pattern to match whatever subset of the current
>    set of candidates you want to remove (exclude, subtract).
>
> 2. Then use `C-~' to remove them.
>
> See "Chip Away the Non-Elephant" in the Icicles doc:
> http://www.emacswiki.org//Icicles_-_Nutshell_View#ChippingAway

Thanks for elaborating, Drew.


Let me add: the poor man's version of this - or of doing this similarly
with helm - without using external packages could be reached with M-x
occur combined with M-x hide-lines.  Doesn't offer all the features that
come with these packages, but does the job.

Michael.