The mechanism iswtichb used to show completions - emacs

all.
I decided to hack iswitchb this morning, and found a confusing thing.
Usually,when we command iswitchb,we got someting in minibuffer like:
iswitch {buffer1,buffer2 ...}
What in braces is the completions, as we typing its number
is shrinking.
And I didn't find how iswitchb achieved this when hacking on
its code (sorry for my dullness ).
This is original iswitchb-read-buffer with doc-string ripped
off:
(defun iswitchb-read-buffer (prompt &optional default require-match
start matches-set)
(let
(
buf-sel
iswitchb-final-text
(icomplete-mode nil) ;; prevent icomplete starting up
)
(iswitchb-define-mode-map)
(setq iswitchb-exit nil)
(setq iswitchb-default
(if (bufferp default)
(buffer-name default)
default))
(setq iswitchb-text (or start ""))
(unless matches-set
(setq iswitchb-rescan t)
(iswitchb-make-buflist iswitchb-default)
(iswitchb-set-matches))
(let
((minibuffer-local-completion-map iswitchb-mode-map)
;; Record the minibuffer depth that we expect to find once
;; the minibuffer is set up and iswitchb-entryfn-p is called.
(iswitchb-minibuf-depth (1+ (minibuffer-depth)))
(iswitchb-require-match require-match))
;; prompt the user for the buffer name
(setq iswitchb-final-text (completing-read
prompt ;the prompt
'(("dummy" . 1)) ;table
nil ;predicate
nil ;require-match [handled elsewhere]
start ;initial-contents
'iswitchb-history)))
(if (and (not (eq iswitchb-exit 'usefirst))
(get-buffer iswitchb-final-text))
;; This happens for example if the buffer was chosen with the mouse.
(setq iswitchb-matches (list iswitchb-final-text)
iswitchb-virtual-buffers nil))
;; If no buffer matched, but a virtual buffer was selected, visit
;; that file now and act as though that buffer had been selected.
(if (and iswitchb-virtual-buffers
(not (iswitchb-existing-buffer-p)))
(let ((virt (car iswitchb-virtual-buffers))
(new-buf))
;; Keep the name of the buffer returned by find-file-noselect, as
;; the buffer 'virt' could be a symlink to a file of a different name.
(setq new-buf (buffer-name (find-file-noselect (cdr virt))))
(setq iswitchb-matches (list new-buf)
iswitchb-virtual-buffers nil)))
;; Handling the require-match must be done in a better way.
(if (and require-match
(not (iswitchb-existing-buffer-p)))
(error "Must specify valid buffer"))
(if (or (eq iswitchb-exit 'takeprompt)
(null iswitchb-matches))
(setq buf-sel iswitchb-final-text)
;; else take head of list
(setq buf-sel (car iswitchb-matches)))
;; Or possibly choose the default buffer
(if (equal iswitchb-final-text "")
(setq buf-sel (car iswitchb-matches)))
buf-sel))
And this is the part of iswitchb-read buffer,which I thought
is responsible for functioning completion mechanism.
(defun iswitchb-read-buffer (prompt &optional default require-match
start matches-set)
(let
(
(iswitchb-minibuf-depth (1+ (minibuffer-depth)))
)
;; prompt the user for the buffer name
(completing-read
prompt ;the prompt
'(("dummy" . 1)) ;table
nil ;predicate
nil ;require-match [handled elsewhere]
start ;initial-contents
'iswitchb-history)))
Eval
(iswitchb-read-buffer "Test: ")
resulting
Test: {buffer1,buffer2,...}
So, I think I'm right.
So,what confused me is how can sexp:
(iswitchb-minibuf-depth (1+ (minibuffer-depth)))
has effect on what echos in minibuffer. Comment this
sexp,or replace iswitchb-minibuffer-depth with another
variable, the completions will disappear.
Any advice?

This variable is used in iswitchb-entryfn-p which is called from iswitchb-minibuffer-setup
(defun iswitchb-minibuffer-setup ()
"Set up minibuffer for `iswitchb-buffer'.
Copied from `icomplete-minibuffer-setup-hook'."
(when (iswitchb-entryfn-p)
(set (make-local-variable 'iswitchb-use-mycompletion) t)
(add-hook 'pre-command-hook 'iswitchb-pre-command nil t)
(add-hook 'post-command-hook 'iswitchb-post-command nil t)
(run-hooks 'iswitchb-minibuffer-setup-hook)))
When iswitchb-minibuf-depth is null then iswitchb-entryfn-p is null and the setup is not done.
The iswitchb-minibuffer-setup is a hook which is added to the iswitchb-mode.

BTW, while this may not directly answer your question, this part of iswitchb's behavior is also provided by icomplete-mode (for the normal completion code).

Related

Emacs jump to next annotated words or phrases

When using Emacs, I notice that words or phrases in a buffer can be annotated or highlighted by many minor modes like hi-lock-mode, flyspell-mode, flycheck-mode...
Is there any uniform way to jump to the highlighted words or phrases created by all these minor modes? Specifically, is there any package or function support jumping to the next and previous highlighted phrases?
When using Eclipse, I can do it by pressing Ctrl-. and Ctrl-,. However, when switching to Emacs, so far, I haven't found an equivalent feature.
Developing a mode which aims to tackle that kind of tasks
https://github.com/andreas-roehler/werkstatt/tree/master/general-key
Facilitates the setting of a general command.
Than this command gets different bindings according to modes - which needs to be edited by hand once. Afterwards it allows to set/change a key at one place for all related/bound commands.
See for example inside
https://github.com/andreas-roehler/werkstatt/blob/master/general-key/general-key-python-mode.el
It's alpha still notably for the install process. Bug reports resp. feature requests welcome.
Not surprisingly, #Drew has answered something related to this.
You can programmatically use isearch with something like:
(defun foo (regexp)
(interactive (list (read-regexp "Regexp: ")))
(isearch-mode t t)
(let ((isearch-regexp nil))
(isearch-yank-string regexp)))
This will pull your previous regexp history, including those from hi-lock. I imagine it would be a fun exercise to modify this to use hi-lock-regexp-history.
If you use swiper, you can restrict the search candidates to lines with highlighted patterns by hi-lock-mode.
Here is a simple wrapper of swiper:
(require 'cl-lib)
(defun swiper-over-highlights-simple ()
(interactive)
(let ((original-swiper--candidates (symbol-function 'swiper--candidates)))
(cl-letf (((symbol-function 'swiper--candidates)
(lambda ()
(let ((pattern (mapconcat #'car hi-lock-interactive-patterns "\\|")))
(cl-remove-if-not (lambda (x) (string-match-p pattern x))
(funcall original-swiper--candidates))))))
(swiper))))
In addition, you can change ivy-read's preselect argument, which initializes the first matched line inside swiper.
The following fuction, modified from swiper, finds the closest next line with a highlighted pattern:
(defun swiper-over-highlights (&optional initial-input)
(interactive)
(let ((original-swiper--candidates (symbol-function 'swiper--candidates))
(pattern (mapconcat #'car hi-lock-interactive-patterns "\\|")))
(cl-letf (((symbol-function 'swiper--candidates)
(lambda ()
(cl-remove-if-not (lambda (x) (string-match-p pattern x))
(funcall original-swiper--candidates)))))
(let ((candidates (swiper--candidates)))
(swiper--init)
(setq swiper-invocation-face
(plist-get (text-properties-at (point)) 'face))
(let ((preselect
(save-excursion
(search-forward-regexp pattern nil t)
(let* ((current-line-value (current-line))
(candidate-line-numbers (mapcar (lambda (x) (cadr (text-properties-at 0 x)))
candidates))
(preselect-line-num (cl-find-if (lambda (x) (<= current-line-value x))
candidate-line-numbers)))
(- (length candidate-line-numbers)
(length (member preselect-line-num candidate-line-numbers))))))
(minibuffer-allow-text-properties t)
res)
(unwind-protect
(and
(setq res
(ivy-read
"Swiper: "
candidates
:initial-input initial-input
:keymap swiper-map
:preselect preselect
:require-match t
:action #'swiper--action
:re-builder #'swiper--re-builder
:history 'swiper-history
:extra-props (list :fname (buffer-file-name))
:caller 'swiper))
(point))
(unless (or res swiper-stay-on-quit)
(goto-char swiper--opoint))
(isearch-clean-overlays)
(unless (or res (string= ivy-text ""))
(cl-pushnew ivy-text swiper-history))
(setq swiper--current-window-start nil)
(when swiper--reveal-mode
(reveal-mode 1))))))))

Emacs: swapping replace queries

Using query-replace, the minibuffer says this (having saved the previous arguments):
Query replace (default FROM -> TO)
is there a command to swap the args? To get this:
Query replace (default TO -> FROM)
AFAIK, nothing out of the box does that for you. But IMHO you don't need that.
All you need to do is use M-p. Use it once to get the last TO you used. Then repeat M-p a couple times to get the last FROM you used. Very quick.
After that, you can use C-x ESC ESC (or C-x M-: or C-x M-ESC), possibly followed by M-p, to repeat either combination (TO -> FROM or FROM -> TO).
(defun swap-query-replace-defaults ()
"Swap the initial expressions offered by `query-replace'. "
(interactive)
(let* ((erg query-replace-defaults)
(first (car erg))
(second (cdr erg)))
(setq query-replace-defaults (cons second first))
(when (interactive-p) (message "%s" query-replace-defaults))
query-replace-defaults))
Made a feature-request:
http://lists.gnu.org/archive/html/bug-gnu-emacs/2013-10/msg00102.html
There's a shortcut to swap the args: M-p RET M-p M-p RET
I use this:
;; Redefine `query-replace-read-from' to add a custom keymap when
;; replacing strings. Now, C-u ENTER does the reverse suggested
;; replacement.
(defvar query-replace-keymap
(let ((map (make-sparse-keymap)))
(set-keymap-parent map minibuffer-local-map)
(define-key map [remap exit-minibuffer]
(lambda ()
(interactive)
(if (and current-prefix-arg query-replace-defaults)
(setq query-replace-defaults
(cons
(cdr query-replace-defaults)
(car query-replace-defaults))))
(exit-minibuffer)))
map))
(defun query-replace-read-from (prompt regexp-flag)
"Query and return the `from' argument of a query-replace operation.
The return value can also be a pair (FROM . TO) indicating that the user
wants to replace FROM with TO."
(if query-replace-interactive
(car (if regexp-flag regexp-search-ring search-ring))
(let* ((history-add-new-input nil)
(query-replace-defaults query-replace-defaults)
(prompt
(if query-replace-defaults
(format "%s (default %s -> %s): " prompt
(query-replace-descr (car query-replace-defaults))
(query-replace-descr (cdr query-replace-defaults)))
(format "%s: " prompt)))
(from
;; The save-excursion here is in case the user marks and copies
;; a region in order to specify the minibuffer input.
;; That should not clobber the region for the query-replace itself.
(save-excursion
(if regexp-flag
(read-regexp prompt nil query-replace-from-history-variable)
(read-from-minibuffer
prompt nil query-replace-keymap nil query-replace-from-history-variable
(car (if regexp-flag regexp-search-ring search-ring)) t)))))
(if (and (zerop (length from)) query-replace-defaults)
(cons (car query-replace-defaults)
(query-replace-compile-replacement
(cdr query-replace-defaults) regexp-flag))
(add-to-history query-replace-from-history-variable from nil t)
;; Warn if user types \n or \t, but don't reject the input.
(and regexp-flag
(string-match "\\(\\`\\|[^\\]\\)\\(\\\\\\\\\\)*\\(\\\\[nt]\\)" from)
(let ((match (match-string 3 from)))
(cond
((string= match "\\n")
(message "Note: `\\n' here doesn't match a newline; to do that, type C-q C-j instead"))
((string= match "\\t")
(message "Note: `\\t' here doesn't match a tab; to do that, just type TAB")))
(sit-for 2)))
from))))

Shortcut for inserting environments in `org-mode`

I'm using org-mode for organizing myself (very useful so far!). However, it is kind of annoying writting
#+begin_comment
...
#+end_comment
each time I'd like to insert an environment.
Question
Is there a shortcut to insert the #+begin_ and #+end_ for a given environment?
In the same way C-c C-o comment RET would insert
\begin{comment}
\end{comment}
in latex-mode.
Org has a facility called "Easy templates": http://orgmode.org/manual/Easy-Templates.html
A template for comment is missing but you can add it with:
(add-to-list 'org-structure-template-alist '("C" "#+begin_comment\n?\n#+end_comment"))
And use it by typing <C followed by TAB.
Alternatively, you could use yasnippet.
Now the corresponding template section is called Structure Template and the insertion sequence is invoked by C-c C-,. I didn't (require 'org-tempo) which is described to support insertion keys like <s TAB.
The comment environment is already defined in org-structure-template-alist. So the comment would be inserted by
C-c C-, C
It's still possible to add a user defined sequence by, for example,
C-c C-, [TAB|RET|SPC] src python :results output :session
delivering
#+begin_src python :results output :session
#+end_src
(emacs 25.2.2, org-mode 9.2)
You could have a look at "org-auctex-keys.el", a minor mode which I created to offer AUCTeX key bindings within Org documents.
In this case, you'd use C-c C-e to insert an environment (prompt to enter the environment name), as what AUCTeX does.
If you're interested, check it out at https://github.com/fniessen/org-auctex-key-bindings.
Not as elegant as the answer of Michael Markert but maybe more expandable.
1) You can select a region and put the block around it or you can just put the block at point.
2) Keyword expansion and history.
3) Keystrokes: C-c b
The command could be further expanded. E.g., for the src block the various switches like -n -r and export to files could be supported.
(defun list-major-modes ()
"Returns list of potential major mode names (without the final -mode).
Note, that this is guess work."
(interactive)
(let (l)
(mapatoms #'(lambda (f) (and
(commandp f)
(string-match "-mode$" (symbol-name f))
;; auto-loaded
(or (and (autoloadp (symbol-function f))
(let ((doc (documentation f)))
(when doc
(and
(let ((docSplit (help-split-fundoc doc f)))
(and docSplit ;; car is argument list
(null (cdr (read (car docSplit)))))) ;; major mode starters have no arguments
(if (string-match "[mM]inor" doc) ;; If the doc contains "minor"...
(string-match "[mM]ajor" doc) ;; it should also contain "major".
t) ;; else we cannot decide therefrom
))))
(null (help-function-arglist f)))
(setq l (cons (substring (symbol-name f) 0 -5) l)))))
(when (called-interactively-p 'any)
(with-current-buffer (get-buffer-create "*Major Modes*")
(clear-buffer-delete)
(let ((standard-output (current-buffer)))
(display-completion-list l)
(display-buffer (current-buffer)))))
l))
(defvar org-insert-block-hist nil
"History for command `org-insert-block'")
(defvar org-insert-block-hist/src:major nil
"History for major mode in org src blocks.")
(defvar org-insert-block-list (append org-protecting-blocks
'("comment" ""))
"List of block types offered as completion for command `org-insert-block'")
;; block_src switches: -n () -r (references) -l "((%s))" (label format) -k (keep labels)
(defvar org-insert-block-list-specials
"Assoc list of Commands for reading additional specification of org-blocks.")
(setq org-insert-block-list-specials
'(("src" . (concat " " (completing-read "Major mode:"
(list-major-modes)
nil nil
(car org-insert-block-hist/src:major)
'(org-insert-block-hist/src:major . 1)
)))))
(defun org-insert-block (bl &optional b e attributes)
"Put region between b and e into org-block of kind bl.
If b or e is nil then put org-block limiters around point.
The string attributes is inserted behind the string #+begin_... "
(interactive
(let ((usereg (use-region-p))
(blKind (completing-read "Input block kind (tab: completion, uparrow: history):"
org-insert-block-list nil nil (car org-insert-block-hist) '(org-insert-block-hist . 1))))
(list
blKind
(when usereg (region-beginning))
(when usereg (region-end))
(let ((spec (assoc blKind org-insert-block-list-specials)))
(when spec (eval (cdr spec)))
))))
(let ((begBlock (concat "\n#+begin_" bl attributes "\n"))
(endBlock (concat "\n#+end_" bl "\n")))
(if (and b e)
(save-restriction
(narrow-to-region b e)
(goto-char (point-min))
(insert begBlock)
(goto-char (point-max))
(insert endBlock)
(indent-region (point-min) (point-max)))
(let ((p (point)))
(insert endBlock)
(goto-char p)
(insert begBlock))
)))
(add-hook 'org-mode-hook '(lambda ()
(local-set-key (kbd "C-c b") 'org-insert-block)))

Asking emacs for default directory path "once"

I want to have a variable that keeps the default directory a user enters and keep using it throughout the run of emacs.
Basically, when the user executes a custom command, the prompt will ask for a default directory path to execute the command (only once) and whenever the user calls the same command emacs uses the same path onward.
How can I program that snippet of code in lisp?
I basically want this code in the igrep library to accept the input from user once and not ask again:
(defvar default-files-string-new "*.[sch]")
(defun igrep-read-files (&optional prompt-prefix)
"Read and return a file name pattern from the minibuffer.
If `current-prefix-arg' is '(16) or '(64), read multiple file name
patterns and return them in a list. Optional PROMPT-PREFIX is
prepended to the \"File(s): \" prompt."
(let* ((default-files (igrep-default-files))
(default-files-string (mapconcat 'identity default-files " "))
(insert-default-directory igrep-insert-default-directory)
(file (igrep-read-file-name
(igrep-prefix prompt-prefix
(if default-files
(format "File(s) [default: %s]: "
default-files-string)
"File(s): "))
nil (if default-files default-files-string "") nil nil
'igrep-files-history))
(files (list file)))
(if (or igrep-read-multiple-files
(and (consp current-prefix-arg)
(memq (prefix-numeric-value current-prefix-arg)
'(16 64))))
(let* ((key (igrep-default-key 'exit-minibuffer
minibuffer-local-completion-map
"\r"))
(prompt
(igrep-prefix prompt-prefix
(if igrep-verbose-prompts
(format "File(s): [Type `%s' when done] "
(key-description key))
"File(s): "))))
(while (and (setq file
(igrep-read-file-name prompt
nil "" nil nil
'igrep-files-history))
(not (equal file "")))
(setq files (cons file files)))))
(mapcar (lambda (file)
(if (file-directory-p file)
;; really should map expand-file-name over default-files:
(expand-file-name (if default-files default-files-string-new "*")
file)
file))
(nreverse files))))
You could use advices to do that:
(defvar wd-alist nil)
(mapc
(lambda (function)
(eval
`(defadvice ,function (around ,(intern (format "%s-wd" function)) activate)
(let ((wd (cdr (assoc ',function wd-alist))))
(unless wd
(setq wd (read-file-name "Default directory: "))
(push (cons ',function wd) wd-alist))
(let ((default-directory wd))
ad-do-it)))))
'(grep-find))
The variable wd-list stores the association (FUNCTION . PATH). The list mapc iterate over are the advised functions. Now, when calling find-grep, it asks for the working directory (after interactive arguments, so you first have to type the pattern and enter...) and stores it in wd-list for further use. Now your find-grep are always done in that directory.
You could have a custom variable for the sane default, and then have the user enter the path or accept the default on the first call.
(defcustom default-path "/tmp/foo" "Path")
(setq current-path nil)
(defun foo ()
(interactive)
(unless current-path
(setq current-path
(read-from-minibuffer
(format "Path [%s]" default-path) nil nil t nil default-path)))
(message "Path is: %s" current-path))
The first time you do M-x foo, it prompts for the path. A common idiom is to allow the user to specify a prefix argument when they want to change the value (after the first time.) This code will have the desired effect:
(defun foo (choose)
(interactive "P")
(when (or choose (not current-path))
(setq current-path
(read-from-minibuffer
(format "Path [%s]" default-path) nil nil t nil default-path)))
(message "Path is: %s" current-path))
Now doing M-x foo is the same as before, but C-0 M-x foo will prompt for a new value.
In your example, something like this will work.
(defun igrep-read-files (&optional prompt-prefix)
(interactive "P")
(when (or prompt-prefix (not current-path ))
(setq current-path
(read-file-name "Dir: " default-path nil t)))
(message (expand-file-name default-files-string-new current-path)))
Have a look at the code of sendmail-query-once.
Although it's not very fashionable to do this sort of thing.
Usually package writers pick a sane default and let the user
customize it as they want.

How do I get the region (selection) programmatically in Emacs Lisp?

I need to access the selection in Emacs buffer.
I have found this article How do I access the contents of the current region in Emacs Lisp?
and it helps me a lot.
But there is a problem. The first time I select (highlight) a region, it works okay, but when I press C-g, and move cursor normally to another place without highlighting any chars, I got a string from last mark to the current point while I expect an empty one.
Actually I need to implement a function which will return the current selection (highlighted) as a string, or empty string if nothing is highlighted. The following code may express me more clearly.
(defun get-search-term ()
(interactive)
(let (
(selection (buffer-substring-no-properties (region-beginning) (region-end))))
(if (= (length selection) 0)
(message "empty string")
(message selection))))
Any suggestions? Thanks a lot!
"r" specification of interactive is dumb. You're seeing why.
(defun get-search-term (beg end)
"message region or \"empty string\" if none highlighted"
(interactive (if (use-region-p)
(list (region-beginning) (region-end))
(list (point-min) (point-min))))
(let ((selection (buffer-substring-no-properties beg end)))
(if (= (length selection) 0)
(message "empty string")
(message selection))))
I don't mean "dumb" as in stupid and not useful; just that it doesn't care
about whether the mark is active or not. I think it predates
transient-mark-mode.
EDIT: Using (point-min) twice above makes the code harder to understand
when re-reading. Here is a better implementation:
(defun get-search-term (beg end)
"message region or \"empty string\" if none highlighted"
(interactive (if (use-region-p)
(list (region-beginning) (region-end))
(list nil nil)))
(message "%s" (if (and beg end)
(buffer-substring-no-properties beg end)
"empty string")))
Check variable mark-active eg. C-h v mark-active
==> mark-active is a variable defined in `C source code'.
Its value is nil
Local in buffer Apropos; global value is nil
Automatically becomes buffer-local when set in any fashion.
Documentation:
Non-nil means the mark and region are currently active in this buffer.
(defun get-search-term ()
(interactive)
(if mark-active
(let (
(selection (buffer-substring-no-properties (region-beginning) (region-end))))
(if (= (length selection) 0)
(message "empty string")
(message selection))
)
(error "mark not active"))
)