tvl-depot/users/glittershark/emacs.d/utils.el
Griffin Smith a89c2f9bd8 feat(gs/emacs): Add an "average" util function
I've been using this in some literate org scripts lately

Change-Id: I42830fb30dd77c9b04fcc9373cafcef05fa8b837
Reviewed-on: https://cl.tvl.fyi/c/depot/+/1322
Tested-by: BuildkiteCI
Reviewed-by: glittershark <grfn@gws.fyi>
2020-07-20 15:51:24 +00:00

114 lines
3.3 KiB
EmacsLisp

;;; private/grfn/utils.el -*- lexical-binding: t; -*-
;; Elisp Extras
(defmacro comment (&rest _body)
"Comment out one or more s-expressions"
nil)
(defun inc (x) "Returns x + 1" (+ 1 x))
(defun dec (x) "Returns x - 1" (- x 1))
(defun average (ns)
"Arithmetic mean of xs"
(if (null ns) nil
(/ (apply #'+ ns)
(length ns))))
(comment
(average (list 1 2 3 4))
)
;;
;; Text editing utils
;;
;; Reading strings
(defun get-char (&optional point)
"Get the character at the given `point' (defaulting to the current point),
without properties"
(let ((point (or point (point))))
(buffer-substring-no-properties point (+ 1 point))))
(defun get-line (&optional lineno)
"Read the line number `lineno', or the current line if `lineno' is nil, and
return it as a string stripped of all text properties"
(let ((current-line (line-number-at-pos)))
(if (or (not lineno)
(= current-line lineno))
(thing-at-point 'line t)
(save-mark-and-excursion
(line-move (- lineno (line-number-at-pos)))
(thing-at-point 'line t)))))
(defun get-line-point ()
"Get the position in the current line of the point"
(- (point) (line-beginning-position)))
;; Moving in the file
(defun goto-line-char (pt)
"Moves the point to the given position expressed as an offset from the start
of the line"
(goto-char (+ (line-beginning-position) pt)))
(defun goto-eol ()
"Moves to the end of the current line"
(goto-char (line-end-position)))
(defun goto-regex-on-line (regex)
"Moves the point to the first occurrence of `regex' on the current line.
Returns nil if the regex did not match, non-nil otherwise"
(when-let ((current-line (get-line))
(line-char (string-match regex current-line)))
(goto-line-char line-char)))
(defun goto-regex-on-line-r (regex)
"Moves the point to the *last* occurrence of `regex' on the current line.
Returns nil if the regex did not match, non-nil otherwise"
(when-let ((current-line (get-line))
(modified-regex (concat ".*\\(" regex "\\)"))
(_ (string-match modified-regex current-line))
(match-start (match-beginning 1)))
(goto-line-char match-start)))
(comment
(progn
(string-match (rx (and (zero-or-more anything)
(group "foo" "foo")))
"foofoofoo")
(match-beginning 1)))
;; Changing file contents
(defun delete-line ()
"Remove the line at the current point"
(delete-region (line-beginning-position)
(inc (line-end-position))))
(defmacro modify-then-indent (&rest body)
"Modify text in the buffer according to body, then re-indent from where the
cursor started to where the cursor ended up, then return the cursor to where
it started."
`(let ((beg (line-beginning-position))
(orig-line-char (- (point) (line-beginning-position))))
(atomic-change-group
(save-mark-and-excursion
,@body
(evil-indent beg (+ (line-end-position) 1))))
(goto-line-char orig-line-char)))
(pcase-defmacro s-starts-with (prefix)
`(pred (s-starts-with-p ,prefix)))
(pcase-defmacro s-contains (needle &optional ignore-case)
`(pred (s-contains-p ,needle
,@(when ignore-case (list ignore-case)))))
(comment
(pcase "foo"
((s-contains "bar") 1)
((s-contains "o") 2))
)