Programmatically do shift selection - emacs

Given a beginning position (b) and an end position (e), I want to perform the same action that one does by hitting the movement keys with shift from b to e, but in elisp. The selection can be cancelled by any movement key without shift, so set-mark-command is not what I want.

You can try:
(defun my-mark-region-as-shifted (other-end)
(let ((pos (point)))
(goto-char other-end)
(setq-local transient-mark-mode
(cons 'only
(unless (eq transient-mark-mode 'lambda)
transient-mark-mode)))
(push-mark nil nil t)
(goto-char pos)))
This code is mostly lifted from handle-shift-selection.

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))))

Swap parentheses and square brackets in Emacs Paredit

How can I define a command in paredit mode that swaps parentheses and square brackets?
So the task is to turn this, for example:
(blah
(a (b)
c))
into this:
(blah
[a (b)
c])
With paredit mode, move to start of the expression (a ..) and then:
C-M-SPC [ <right> M-s
Without paredit, but still wanting to maintain balanced parens during transitions, move to a and then press C-M-SPC multiple times until error and then (assuming that CUA mode is on):
C-x <timeout> <right> <backspace> <backspace> [ ] <left> C-v
Well that is complex, so let's stick with paredit mode version, and try to make a command out of it. Keyboard Macro Editor tells you the names of commands being used, so you would be able to come up with at least the following code:
(defun my-switch-to-square ()
"Change (..) to [..]."
(interactive)
(mark-sexp --)
(paredit-open-square --)
(right-char --)
(paredit-splice-sexp --))
-- indicates part of code we have not yet decided. After you read documentation of each function in the code, you learn what arguments to pass, and that there is no need to call mark-sexp. After rewriting docstring and adding a call to left-char, the code you end up with would be:
(defun my-switch-to-square ()
"Change |(..) to |[..]. | is point position."
(interactive)
(paredit-open-square 1)
(right-char 1)
(paredit-splice-sexp)
(left-char 1))
The following code does what you request. You can bind swap-parens to whatever key binding you want.
(defvar swap-paren-pairs '("()" "[]"))
(defun swap-parens-at-points (b e)
(let ((open-char (buffer-substring b (+ b 1)))
(paren-pair-list (append swap-paren-pairs swap-paren-pairs)))
(while paren-pair-list
(if (eq (aref open-char 0) (aref (car paren-pair-list) 0))
(save-excursion
(setq to-replace (cadr paren-pair-list))
(goto-char b)
(delete-char 1)
(insert (aref to-replace 0))
(goto-char (- e 1))
(delete-char 1)
(insert (aref to-replace 1))
(setq paren-pair-list nil))
(setq paren-pair-list (cdr paren-pair-list))))))
(defun swap-parens ()
(interactive)
(cond ((looking-at "\\s(")
(swap-parens-at-points (point) (save-excursion (forward-sexp) (point))))
((and (> (point) 1) (save-excursion (forward-char -1) (looking-at "\\s)")))
(swap-parens-at-points (save-excursion (forward-sexp -1) (point)) (point)))
((message "Not at a paren"))))
I'm not sure what you mean by "define command"? You can do it like this:
|(foo bar)
"|" is point.
;; Keyboard Macro Editor. Press C-c C-c to finish; press C-x k RET to cancel.
;; Original keys: C-u [ C-f <M-up> C-b
Command: last-kbd-macro
Key: none
Macro:
C-u [ ;; paredit-open-square
C-f ;; forward-char
<M-up> ;; paredit-splice-sexp-killing-backward
C-b ;; backward-char
Although to be honest, this type of usage scenario is more common for VIM trickery. I've never actually used this IRL.
bzr branch lp:s-x-emacs-werkstatt
will deliver a library inspired by paredit, but delivering more detailed commands
M-x ar-bracket-parentized-atpt RET
puts brackets around parenteses at point
look inside thing-at-point-utils.el and the other files what else is provided

Permanently change the state of abbreviated display of a piece of code?

In *scratch* buffer in Emacs Lisp after you evaluated an expression that evaluates to a complex Lisp form, that form is "abbreviated", i.e. some long lists or its inner parts are replaced by ellipses. Looks something like:
(let* ((--3 (make-hash-table)) d c (--5 (let ... ... ...)) (--6 0) (--0 (make-
hash-table)) b a (--1 0) --7) (catch (quote --2) (maphash (lambda ... ... ...
... ... ... ...) --0)) (nreverse --7))
vs expanded version:
(let* ((--3 (make-hash-table)) d c (--5 (let (--4) (maphash (lambda (k v)
(setq --4(cons k --4))) --3) (nreverse --4))) (--6 0) (--0 (make-hash-table))
b a (--1 0) --7) (catch (quote --2) (maphash (lambda (k v) (when (or (> --6
150) (> --1 100)) (throw (quote --2) nil)) (setq a k b v) (setq c (car --5) d
(gethash (car --5) --3) --5 (cdr --5)) (incf --6) (setq --7 (cons (list (cons
a b) (cons c d)) --7)) (message "a: %s, b: %s, c: %s, d: %s" a b c d)) --0))
(nreverse --7))
If I press RET in the expanded or collapsed state, it toggles the state back. Obviously, my first reaction is to try to format the output, so I press RET! And then it will either collapse or expand, depends on whichever state it was in. If I copy and paste the whole thing, then it is treated as normal text, but is there a faster way of doing it? I.e. I would like to permanently expand it, w/o having to copy-paste.
I couldn't find the function which toggles the state (perhaps I'm calling it incorrectly). It took me a while to realize it was possible to toggle it anyway (yeah, it displays that in a tooltip, but who uses mouse in Emacs?).
Also, I, in general, like the idea, is it possible to apply it to other languages too? Where can I read more about this feature?
Two variables control the print out of results of eval-expression. in the *scratch* buffer:
eval-expression-print-length
eval-expression-print-level
You could set those to nil and the result would always be expanded.
If you just want the RET to switch to the fully expanded (and not to toggle), you can use this advice to strip the text properties which enable the toggling of display state:
(defadvice last-sexp-toggle-display (after last-sexp-toggle-display-only-long-form activate)
"After the function is called, check to see if the long form had been displayed, and if so, remove property enabling toggling"
(save-restriction
(widen)
(let ((value (get-text-property (point) 'printed-value)))
(when value
(let ((beg (or (previous-single-property-change (min (point-max) (1+ (point)))
'printed-value)
(point)))
(end (or (next-single-char-property-change (point) 'printed-value) (point)))
(standard-output (current-buffer))
(point (point)))
(if (< (length (nth 1 value)) (length (nth 2 value)))
(remove-text-properties beg end '(printed-value))))))))

The mechanism iswtichb used to show completions

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).