diff options
Diffstat (limited to 'lisp/emacs-lisp/subr-x.el')
| -rw-r--r-- | lisp/emacs-lisp/subr-x.el | 218 |
1 files changed, 199 insertions, 19 deletions
diff --git a/lisp/emacs-lisp/subr-x.el b/lisp/emacs-lisp/subr-x.el index 4548d749fe8..1d729f94092 100644 --- a/lisp/emacs-lisp/subr-x.el +++ b/lisp/emacs-lisp/subr-x.el @@ -33,6 +33,7 @@ ;;; Code: (require 'pcase) +(eval-when-compile (require 'cl-lib)) (defmacro internal--thread-argument (first? &rest forms) @@ -114,14 +115,19 @@ threading." binding)) bindings))) -(defmacro if-let (bindings then &rest else) - "Process BINDINGS and if all values are non-nil eval THEN, else ELSE. -Argument BINDINGS is a list of tuples whose car is a symbol to be -bound and (optionally) used in THEN, and its cadr is a sexp to be -evalled to set symbol's value. In the special case you only want -to bind a single value, BINDINGS can just be a plain tuple." +(defmacro if-let* (bindings then &rest else) + "Bind variables according to VARLIST and eval THEN or ELSE. +Each binding is evaluated in turn with `let*', and evaluation +stops if a binding value is nil. If all are non-nil, the value +of THEN is returned, or the last form in ELSE is returned. +Each element of VARLIST is a symbol (which is bound to nil) +or a list (SYMBOL VALUEFORM) (which binds SYMBOL to the value of VALUEFORM). +In the special case you only want to bind a single value, +VARLIST can just be a plain tuple. +\n(fn VARLIST THEN ELSE...)" (declare (indent 2) - (debug ([&or (&rest (symbolp form)) (symbolp form)] form body))) + (debug ([&or (&rest [&or symbolp (symbolp form)]) (symbolp form)] + form body))) (when (and (<= (length bindings) 2) (not (listp (car bindings)))) ;; Adjust the single binding case @@ -131,30 +137,34 @@ to bind a single value, BINDINGS can just be a plain tuple." ,then ,@else))) -(defmacro when-let (bindings &rest body) - "Process BINDINGS and if all values are non-nil eval BODY. -Argument BINDINGS is a list of tuples whose car is a symbol to be -bound and (optionally) used in BODY, and its cadr is a sexp to be -evalled to set symbol's value. In the special case you only want -to bind a single value, BINDINGS can just be a plain tuple." +(defmacro when-let* (bindings &rest body) + "Bind variables according to VARLIST and conditionally eval BODY. +Each binding is evaluated in turn with `let*', and evaluation +stops if a binding value is nil. If all are non-nil, the value +of the last form in BODY is returned. +Each element of VARLIST is a symbol (which is bound to nil) +or a list (SYMBOL VALUEFORM) (which binds SYMBOL to the value of VALUEFORM). +In the special case you only want to bind a single value, +VARLIST can just be a plain tuple. +\n(fn VARLIST BODY...)" (declare (indent 1) (debug if-let)) (list 'if-let bindings (macroexp-progn body))) +(defalias 'if-let 'if-let*) +(defalias 'when-let 'when-let*) +(defalias 'and-let* 'when-let*) + (defsubst hash-table-empty-p (hash-table) "Check whether HASH-TABLE is empty (has 0 elements)." (zerop (hash-table-count hash-table))) (defsubst hash-table-keys (hash-table) "Return a list of keys in HASH-TABLE." - (let ((keys '())) - (maphash (lambda (k _v) (push k keys)) hash-table) - keys)) + (cl-loop for k being the hash-keys of hash-table collect k)) (defsubst hash-table-values (hash-table) "Return a list of values in HASH-TABLE." - (let ((values '())) - (maphash (lambda (_k v) (push v values)) hash-table) - values)) + (cl-loop for v being the hash-values of hash-table collect v)) (defsubst string-empty-p (string) "Check whether STRING is empty." @@ -198,6 +208,176 @@ to bind a single value, BINDINGS can just be a plain tuple." (substring string 0 (- (length string) (length suffix))) string)) +(defun read-multiple-choice (prompt choices) + "Ask user a multiple choice question. +PROMPT should be a string that will be displayed as the prompt. + +CHOICES is an alist where the first element in each entry is a +character to be entered, the second element is a short name for +the entry to be displayed while prompting (if there's room, it +might be shortened), and the third, optional entry is a longer +explanation that will be displayed in a help buffer if the user +requests more help. + +This function translates user input into responses by consulting +the bindings in `query-replace-map'; see the documentation of +that variable for more information. In this case, the useful +bindings are `recenter', `scroll-up', and `scroll-down'. If the +user enters `recenter', `scroll-up', or `scroll-down' responses, +perform the requested window recentering or scrolling and ask +again. + +When `use-dialog-box' is t (the default), this function can pop +up a dialog window to collect the user input. That functionality +requires `display-popup-menus-p' to return t. Otherwise, a text +dialog will be used. + +The return value is the matching entry from the CHOICES list. + +Usage example: + +\(read-multiple-choice \"Continue connecting?\" + \\='((?a \"always\") + (?s \"session only\") + (?n \"no\")))" + (let* ((altered-names nil) + (full-prompt + (format + "%s (%s): " + prompt + (mapconcat + (lambda (elem) + (let* ((name (cadr elem)) + (pos (seq-position name (car elem))) + (altered-name + (cond + ;; Not in the name string. + ((not pos) + (format "[%c] %s" (car elem) name)) + ;; The prompt character is in the name, so highlight + ;; it on graphical terminals... + ((display-supports-face-attributes-p + '(:underline t) (window-frame)) + (setq name (copy-sequence name)) + (put-text-property pos (1+ pos) + 'face 'read-multiple-choice-face + name) + name) + ;; And put it in [bracket] on non-graphical terminals. + (t + (concat + (substring name 0 pos) + "[" + (upcase (substring name pos (1+ pos))) + "]" + (substring name (1+ pos))))))) + (push (cons (car elem) altered-name) + altered-names) + altered-name)) + (append choices '((?? "?"))) + ", "))) + tchar buf wrong-char answer) + (save-window-excursion + (save-excursion + (while (not tchar) + (message "%s%s" + (if wrong-char + "Invalid choice. " + "") + full-prompt) + (setq tchar + (if (and (display-popup-menus-p) + last-input-event ; not during startup + (listp last-nonmenu-event) + use-dialog-box) + (x-popup-dialog + t + (cons prompt + (mapcar + (lambda (elem) + (cons (capitalize (cadr elem)) + (car elem))) + choices))) + (condition-case nil + (let ((cursor-in-echo-area t)) + (read-char)) + (error nil)))) + (setq answer (lookup-key query-replace-map (vector tchar) t)) + (setq tchar + (cond + ((eq answer 'recenter) + (recenter) t) + ((eq answer 'scroll-up) + (ignore-errors (scroll-up-command)) t) + ((eq answer 'scroll-down) + (ignore-errors (scroll-down-command)) t) + ((eq answer 'scroll-other-window) + (ignore-errors (scroll-other-window)) t) + ((eq answer 'scroll-other-window-down) + (ignore-errors (scroll-other-window-down)) t) + (t tchar))) + (when (eq tchar t) + (setq wrong-char nil + tchar nil)) + ;; The user has entered an invalid choice, so display the + ;; help messages. + (when (and (not (eq tchar nil)) + (not (assq tchar choices))) + (setq wrong-char (not (memq tchar '(?? ?\C-h))) + tchar nil) + (when wrong-char + (ding)) + (with-help-window (setq buf (get-buffer-create + "*Multiple Choice Help*")) + (with-current-buffer buf + (erase-buffer) + (pop-to-buffer buf) + (insert prompt "\n\n") + (let* ((columns (/ (window-width) 25)) + (fill-column 21) + (times 0) + (start (point))) + (dolist (elem choices) + (goto-char start) + (unless (zerop times) + (if (zerop (mod times columns)) + ;; Go to the next "line". + (goto-char (setq start (point-max))) + ;; Add padding. + (while (not (eobp)) + (end-of-line) + (insert (make-string (max (- (* (mod times columns) + (+ fill-column 4)) + (current-column)) + 0) + ?\s)) + (forward-line 1)))) + (setq times (1+ times)) + (let ((text + (with-temp-buffer + (insert (format + "%c: %s\n" + (car elem) + (cdr (assq (car elem) altered-names)))) + (fill-region (point-min) (point-max)) + (when (nth 2 elem) + (let ((start (point))) + (insert (nth 2 elem)) + (unless (bolp) + (insert "\n")) + (fill-region start (point-max)))) + (buffer-string)))) + (goto-char start) + (dolist (line (split-string text "\n")) + (end-of-line) + (if (bolp) + (insert line "\n") + (insert line)) + (forward-line 1))))))))))) + (when (buffer-live-p buf) + (kill-buffer buf)) + (assq tchar choices))) + (provide 'subr-x) ;;; subr-x.el ends here |