| 1 | ;;; levents.el --- emulate the Lucid event data type and associated functions. |
| 2 | |
| 3 | ;; Copyright (C) 1993 Free Software Foundation, Inc. |
| 4 | |
| 5 | ;; This file is part of GNU Emacs. |
| 6 | |
| 7 | ;; GNU Emacs is free software; you can redistribute it and/or modify |
| 8 | ;; it under the terms of the GNU General Public License as published by |
| 9 | ;; the Free Software Foundation; either version 2, or (at your option) |
| 10 | ;; any later version. |
| 11 | |
| 12 | ;; GNU Emacs is distributed in the hope that it will be useful, |
| 13 | ;; but WITHOUT ANY WARRANTY; without even the implied warranty of |
| 14 | ;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| 15 | ;; GNU General Public License for more details. |
| 16 | |
| 17 | ;; You should have received a copy of the GNU General Public License |
| 18 | ;; along with GNU Emacs; see the file COPYING. If not, write to |
| 19 | ;; the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA. |
| 20 | |
| 21 | ;;; Commentary: |
| 22 | |
| 23 | ;; Things we cannot emulate in Lisp: |
| 24 | ;; It is not possible to emulate current-mouse-event as a variable, |
| 25 | ;; though it is not hard to obtain the data from (this-command-keys). |
| 26 | |
| 27 | ;; We do not have a variable unread-command-event; |
| 28 | ;; instead, we have the more general unread-command-events. |
| 29 | |
| 30 | ;; Our read-key-sequence and read-char are not precisely |
| 31 | ;; compatible with those in Lucid Emacs, but they should work ok. |
| 32 | |
| 33 | ;;; Code: |
| 34 | |
| 35 | (defun next-command-event (event) |
| 36 | (error "You must rewrite to use `read-command-event' instead of `next-command-event'")) |
| 37 | |
| 38 | (defun next-event (event) |
| 39 | (error "You must rewrite to use `read-event' instead of `next-event'")) |
| 40 | |
| 41 | (defun dispatch-event (event) |
| 42 | (error "`dispatch-event' not supported")) |
| 43 | |
| 44 | ;; Make events of type eval, menu and timeout |
| 45 | ;; execute properly. |
| 46 | |
| 47 | (define-key global-map [menu] 'execute-eval-event) |
| 48 | (define-key global-map [timeout] 'execute-eval-event) |
| 49 | (define-key global-map [eval] 'execute-eval-event) |
| 50 | |
| 51 | (defun execute-eval-event (event) |
| 52 | (interactive "e") |
| 53 | (funcall (nth 1 event) (nth 2 event))) |
| 54 | |
| 55 | (put 'eval 'event-symbol-elements '(eval)) |
| 56 | (put 'menu 'event-symbol-elements '(eval)) |
| 57 | (put 'timeout 'event-symbol-elements '(eval)) |
| 58 | |
| 59 | (defsubst eventp (obj) |
| 60 | "True if the argument is an event object." |
| 61 | (or (integerp obj) |
| 62 | (and (symbolp obj) |
| 63 | (get obj 'event-symbol-elements)) |
| 64 | (and (consp obj) |
| 65 | (symbolp (car obj)) |
| 66 | (get (car obj) 'event-symbol-elements)))) |
| 67 | |
| 68 | (defun allocate-event () |
| 69 | "Returns an empty event structure. |
| 70 | In this emulation, it returns nil." |
| 71 | nil) |
| 72 | |
| 73 | (defun button-press-event-p (obj) |
| 74 | "True if the argument is a mouse-button-press event object." |
| 75 | (and (consp obj) (symbolp (car obj)) |
| 76 | (memq 'down (get (car obj) 'event-symbol-elements)))) |
| 77 | |
| 78 | (defun button-release-event-p (obj) |
| 79 | "True if the argument is a mouse-button-release event object." |
| 80 | (and (consp obj) (symbolp (car obj)) |
| 81 | (or (memq 'click (get (car obj) 'event-symbol-elements)) |
| 82 | (memq 'drag (get (car obj) 'event-symbol-elements))))) |
| 83 | |
| 84 | (defun character-to-event (ch &optional event) |
| 85 | "Converts a numeric ASCII value to an event structure, replete with |
| 86 | bucky bits. The character is the first argument, and the event to fill |
| 87 | in is the second. This function contains knowledge about what the codes |
| 88 | mean -- for example, the number 9 is converted to the character Tab, |
| 89 | not the distinct character Control-I. |
| 90 | |
| 91 | Beware that character-to-event and event-to-character are not strictly |
| 92 | inverse functions, since events contain much more information than the |
| 93 | ASCII character set can encode." |
| 94 | ch) |
| 95 | |
| 96 | (defun copy-event (event1 &optional event2) |
| 97 | "Make a copy of the given event object. |
| 98 | In this emulation, `copy-event' just returns its argument." |
| 99 | event1) |
| 100 | |
| 101 | (defun deallocate-event (event) |
| 102 | "Allow the given event structure to be reused. |
| 103 | In actual Lucid Emacs, you MUST NOT use this event object after |
| 104 | calling this function with it. You will lose. It is not necessary to |
| 105 | call this function, as event objects are garbage- collected like all |
| 106 | other objects; however, it may be more efficient to explicitly |
| 107 | deallocate events when you are sure that that is safe. |
| 108 | |
| 109 | This emulation does not actually deallocate or reuse events |
| 110 | except via garbage collection and `cons'." |
| 111 | nil) |
| 112 | |
| 113 | (defun enqueue-eval-event: (function object) |
| 114 | "Add an eval event to the back of the queue. |
| 115 | It will be the next event read after all pending events." |
| 116 | (setq unread-command-events |
| 117 | (nconc unread-command-events |
| 118 | (list (list 'eval function object))))) |
| 119 | |
| 120 | (defun eval-event-p (obj) |
| 121 | "True if the argument is an eval or menu event object." |
| 122 | (eq (car-safe obj) 'eval)) |
| 123 | |
| 124 | (defun event-button (event) |
| 125 | "Return the button-number of the given mouse-button-press event." |
| 126 | (let ((sym (car (get (car event) 'event-symbol-elements)))) |
| 127 | (cdr (assq sym '((mouse-1 . 1) (mouse-2 . 2) (mouse-3 . 3) |
| 128 | (mouse-4 . 4) (mouse-5 . 5)))))) |
| 129 | |
| 130 | (defun event-function (event) |
| 131 | "Return the callback function of the given timeout, menu, or eval event." |
| 132 | (nth 1 event)) |
| 133 | |
| 134 | (defun event-key (event) |
| 135 | "Returns the KeySym of the given key-press event. |
| 136 | The value is an ASCII printing character (not upper case) or a symbol." |
| 137 | (if (symbolp event) |
| 138 | (car (get event 'event-symbol-elements)) |
| 139 | (let ((base (logand event (1- (lsh 1 18))))) |
| 140 | (downcase (if (< base 32) (logior base 64) base))))) |
| 141 | |
| 142 | (defun event-object (event) |
| 143 | "Returns the function argument of the given timeout, menu, or eval event." |
| 144 | (nth 2 event)) |
| 145 | |
| 146 | (defun event-point (event) |
| 147 | "Returns the character position of the given mouse-related event. |
| 148 | If the event did not occur over a window, or did |
| 149 | not occur over text, then this returns nil. Otherwise, it returns an index |
| 150 | into the buffer visible in the event's window." |
| 151 | (posn-point (event-end event))) |
| 152 | |
| 153 | (defun event-process (event) |
| 154 | "Returns the process of the given process-output event." |
| 155 | (nth 1 event)) |
| 156 | |
| 157 | (defun event-timestamp (event) |
| 158 | "Returns the timestamp of the given event object. |
| 159 | In Lucid Emacs, this works for any kind of event. |
| 160 | In this emulation, it returns nil for non-mouse-related events." |
| 161 | (and (listp event) |
| 162 | (posn-timestamp (event-end event)))) |
| 163 | |
| 164 | (defun event-to-character (event &optional lenient) |
| 165 | "Returns the closest ASCII approximation to the given event object. |
| 166 | If the event isn't a keypress, this returns nil. |
| 167 | If the second argument is non-nil, then this is lenient in its |
| 168 | translation; it will ignore modifier keys other than control and meta, |
| 169 | and will ignore the shift modifier on those characters which have no |
| 170 | shifted ASCII equivalent (Control-Shift-A for example, will be mapped to |
| 171 | the same ASCII code as Control-A.) If the second arg is nil, then nil |
| 172 | will be returned for events which have no direct ASCII equivalent." |
| 173 | (if (symbolp event) |
| 174 | (and lenient |
| 175 | (cdr (assq event '((backspace . 8) (delete . 127) (tab . 9) |
| 176 | (return . 10) (enter . 10))))) |
| 177 | ;; Our interpretation is, ASCII means anything a number can represent. |
| 178 | (if (integerp event) |
| 179 | event nil))) |
| 180 | |
| 181 | (defun event-window (event) |
| 182 | "Returns the window of the given mouse-related event object." |
| 183 | (posn-window (event-end event))) |
| 184 | |
| 185 | (defun event-x (event) |
| 186 | "Returns the X position in characters of the given mouse-related event." |
| 187 | (/ (car (posn-col-row (event-end event))) |
| 188 | (frame-char-width (window-frame (event-window event))))) |
| 189 | |
| 190 | (defun event-x-pixel (event) |
| 191 | "Returns the X position in pixels of the given mouse-related event." |
| 192 | (car (posn-col-row (event-end event)))) |
| 193 | |
| 194 | (defun event-y (event) |
| 195 | "Returns the Y position in characters of the given mouse-related event." |
| 196 | (/ (cdr (posn-col-row (event-end event))) |
| 197 | (frame-char-height (window-frame (event-window event))))) |
| 198 | |
| 199 | (defun event-y-pixel (event) |
| 200 | "Returns the Y position in pixels of the given mouse-related event." |
| 201 | (cdr (posn-col-row (event-end event)))) |
| 202 | |
| 203 | (defun key-press-event-p (obj) |
| 204 | "True if the argument is a keyboard event object." |
| 205 | (or (integerp obj) |
| 206 | (and (symbolp obj) |
| 207 | (get obj 'event-symbol-elements)))) |
| 208 | |
| 209 | (defun menu-event-p (obj) |
| 210 | "True if the argument is a menu event object." |
| 211 | (eq (car-safe obj) 'menu)) |
| 212 | |
| 213 | (defun motion-event-p (obj) |
| 214 | "True if the argument is a mouse-motion event object." |
| 215 | (eq (car-safe obj) 'mouse-movement)) |
| 216 | |
| 217 | (defun read-command-event () |
| 218 | "Return the next keyboard or mouse event; execute other events. |
| 219 | This is similar to the function `next-command-event' of Lucid Emacs, |
| 220 | but different in that it returns the event rather than filling in |
| 221 | an existing event object." |
| 222 | (let (event) |
| 223 | (while (progn |
| 224 | (setq event (read-event)) |
| 225 | (not (or (key-press-event-p event) |
| 226 | (button-press-event-p event) |
| 227 | (button-release-event-p event) |
| 228 | (menu-event-p event)))) |
| 229 | (let ((type (car-safe event))) |
| 230 | (cond ((eq type 'eval) |
| 231 | (funcall (nth 1 event) (nth 2 event))) |
| 232 | ((eq type 'switch-frame) |
| 233 | (select-frame (nth 1 event)))))) |
| 234 | event)) |
| 235 | |
| 236 | (defun process-event-p (obj) |
| 237 | "True if the argument is a process-output event object. |
| 238 | GNU Emacs 19 does not currently generate process-output events." |
| 239 | (eq (car-safe obj) 'process)) |
| 240 | |
| 241 | (defun timeout-event-p (obj) |
| 242 | "True if the argument is a timeout event object. |
| 243 | GNU Emacs 19 does not currently generate timeout events." |
| 244 | (eq (car-safe obj) 'timeout)) |
| 245 | |
| 246 | ;;; levents.el ends here |