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813f532d RS |
1 | ;;; ielm.el --- interaction mode for Emacs Lisp |
2 | ;; Copyright (C) 1994 Free Software Foundation, Inc. | |
3 | ||
4 | ;; Author: David Smith <maa036@lancaster.ac.uk> | |
5 | ;; Created: 25 Feb 1994 | |
6 | ;; Keywords: lisp | |
7 | ||
8 | ;; This file is part of GNU Emacs. | |
9 | ||
10 | ;; GNU Emacs is free software; you can redistribute it and/or modify | |
11 | ;; it under the terms of the GNU General Public License as published by | |
12 | ;; the Free Software Foundation; either version 2, or (at your option) | |
13 | ;; any later version. | |
14 | ||
15 | ;; GNU Emacs is distributed in the hope that it will be useful, | |
16 | ;; but WITHOUT ANY WARRANTY; without even the implied warranty of | |
17 | ;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
18 | ;; GNU General Public License for more details. | |
19 | ||
20 | ;; You should have received a copy of the GNU General Public License | |
21 | ;; along with GNU Emacs; see the file COPYING. If not, write to | |
22 | ;; the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA. | |
23 | ||
24 | ;;; Commentary: | |
25 | ||
e848854a | 26 | ;; Provides a nice interface to evaluating Emacs Lisp expressions. |
813f532d RS |
27 | ;; Input is handled by the comint package, and output is passed |
28 | ;; through the pretty-printer. | |
29 | ||
30 | ;; To install: copy this file to a directory in your load-path, and | |
e848854a | 31 | ;; add the following line to your .emacs file: |
813f532d | 32 | ;; |
e848854a | 33 | ;; (autoload 'ielm "ielm" "Start an inferior Emacs Lisp session" t) |
813f532d RS |
34 | ;; |
35 | ;; For completion to work, the comint.el from FSF Emacs 19.23 is | |
36 | ;; required. If you do not have it, or if you are running Lemacs, | |
37 | ;; also add the following code to your .emacs: | |
38 | ;; | |
39 | ;; (setq ielm-mode-hook | |
40 | ;; '(lambda nil | |
41 | ;; (define-key ielm-map "\t" | |
42 | ;; '(lambda nil (interactive) (or (ielm-tab) | |
43 | ;; (lisp-complete-symbol)))))) | |
44 | ||
45 | ;; To start: M-x ielm. Type C-h m in the *ielm* buffer for more info. | |
46 | ||
47 | ;; The latest version is available by WWW from | |
48 | ;; http://mathssun5.lancs.ac.uk:2080/~maa036/elisp/dir.html | |
49 | ;; or by anonymous FTP from | |
50 | ;; /anonymous@wingra.stat.wisc.edu:pub/src/emacs-lisp/ielm.el.gz | |
51 | ;; or from the author: David M. Smith <maa036@lancaster.ac.uk> | |
52 | ||
53 | ;;; Code: | |
54 | ||
55 | (require 'comint) | |
56 | (require 'pp) | |
57 | ||
58 | ;;; User variables | |
59 | ||
60 | (defvar ielm-noisy t | |
e848854a | 61 | "*If non-nil, IELM will beep on error.") |
813f532d | 62 | |
e848854a RS |
63 | (defvar ielm-prompt "ELISP> " |
64 | "Prompt used in IELM.") | |
813f532d RS |
65 | |
66 | (defvar ielm-dynamic-return t | |
e848854a RS |
67 | "*Controls whether \\<ielm-map>\\[ielm-return] has intelligent behaviour in IELM. |
68 | If non-nil, \\[ielm-return] evaluates input for complete sexps, or inserts a newline | |
69 | and indents for incomplete sexps. If nil, always inserts newlines.") | |
70 | ||
71 | (defvar ielm-dynamic-multiline-inputs t | |
72 | "*Force multiline inputs to start from column zero? | |
73 | If non-nil, after entering the first line of an incomplete sexp, a newline | |
74 | will be inserted after the prompt, moving the input to the next line. | |
75 | This gives more frame width for large indented sexps, and allows functions | |
76 | such as `edebug-defun' to work with such inputs.") | |
813f532d RS |
77 | |
78 | (defvar ielm-mode-hook nil | |
e848854a | 79 | "*Hooks to be run when IELM (`inferior-emacs-lisp-mode') is started.") |
813f532d RS |
80 | |
81 | ;;; System variables | |
82 | ||
83 | (defvar ielm-working-buffer nil | |
e848854a RS |
84 | "Buffer in which IELM sexps will be evaluated. |
85 | This variable is buffer-local.") | |
813f532d RS |
86 | |
87 | (defvar ielm-header | |
88 | (concat | |
e848854a | 89 | "*** Welcome to IELM version " |
9e983c78 | 90 | (substring "$Revision: 1.3 $" 11 -2) |
813f532d | 91 | " *** Type (describe-mode) for help.\n" |
e848854a RS |
92 | "IELM has ABSOLUTELY NO WARRANTY; type (describe-no-warranty) for details.\n") |
93 | "Message to display when IELM is started.") | |
813f532d RS |
94 | |
95 | (defvar ielm-map nil) | |
96 | (if ielm-map nil | |
97 | (if (string-match "Lucid" emacs-version) | |
98 | ;; Lemacs | |
99 | (progn | |
100 | (setq ielm-map (make-sparse-keymap)) | |
101 | (set-keymap-parent ielm-map comint-mode-map)) | |
102 | ;; FSF | |
103 | (setq ielm-map (cons 'keymap comint-mode-map))) | |
104 | (define-key ielm-map "\t" 'comint-dynamic-complete) | |
105 | (define-key ielm-map "\C-m" 'ielm-return) | |
e848854a RS |
106 | (define-key ielm-map "\C-j" 'ielm-send-input) |
107 | (define-key ielm-map "\e\C-x" 'eval-defun) ; for consistency with | |
108 | (define-key ielm-map "\e\t" 'lisp-complete-symbol) ; lisp-interaction-mode | |
109 | ;; These bindings are from shared-lisp-mode-map -- can you inherit | |
110 | ;; from more than one keymap?? | |
111 | (define-key ielm-map "\e\C-q" 'indent-sexp) | |
112 | (define-key ielm-map "\eq" 'lisp-fill-paragraph) | |
113 | (define-key ielm-map "\177" 'backward-delete-char-untabify) | |
114 | ;; Some convenience bindings for setting the working buffer | |
115 | (define-key ielm-map "\C-c\C-b" 'ielm-change-working-buffer) | |
116 | (define-key ielm-map "\C-c\C-f" 'ielm-display-working-buffer) | |
117 | (define-key ielm-map "\C-c\C-v" 'ielm-print-working-buffer)) | |
813f532d RS |
118 | |
119 | ;;; Completion stuff | |
120 | ||
121 | (defun ielm-tab nil | |
e848854a | 122 | "Possibly indent the current line as lisp code." |
813f532d RS |
123 | (interactive) |
124 | (if (or (eq (preceding-char) ?\n) | |
125 | (eq (char-syntax (preceding-char)) ? )) | |
126 | (progn | |
127 | (ielm-indent-line) | |
128 | t))) | |
129 | ||
130 | (defun ielm-complete-symbol nil | |
e848854a RS |
131 | "Complete the lisp symbol before point." |
132 | ;; A wrapper for lisp-complete symbol that returns non-nil if | |
133 | ;; completion has occurred | |
813f532d | 134 | (let* ((btick (buffer-modified-tick)) |
e58df0dc | 135 | (cbuffer (get-buffer "*Completions*")) |
813f532d RS |
136 | (ctick (and cbuffer (buffer-modified-tick cbuffer)))) |
137 | (lisp-complete-symbol) | |
138 | ;; completion has occurred if: | |
139 | (or | |
140 | ;; the buffer has been modified | |
141 | (not (= btick (buffer-modified-tick))) | |
142 | ;; a completions buffer has been modifed or created | |
143 | (if cbuffer | |
144 | (not (= ctick (buffer-modified-tick cbuffer))) | |
e58df0dc | 145 | (get-buffer "*Completions*"))))) |
813f532d RS |
146 | |
147 | (defun ielm-complete-filename nil | |
e848854a | 148 | "Dynamically complete filename before point, if in a string." |
813f532d RS |
149 | (if (nth 3 (parse-partial-sexp comint-last-input-start (point))) |
150 | (comint-dynamic-complete-filename))) | |
151 | ||
152 | (defun ielm-indent-line nil | |
e848854a | 153 | "Indent the current line as Lisp code if it is not a prompt line." |
813f532d RS |
154 | (if (save-excursion |
155 | (beginning-of-line) | |
156 | (looking-at comint-prompt-regexp)) nil | |
157 | (lisp-indent-line))) | |
158 | ||
e848854a RS |
159 | ;;; Working buffer manipulation |
160 | ||
161 | (defun ielm-print-working-buffer nil | |
162 | "Print the current IELM working buffer's name in the echo area." | |
163 | (interactive) | |
164 | (message "The current working buffer is: %s" (buffer-name ielm-working-buffer))) | |
165 | ||
166 | (defun ielm-display-working-buffer nil | |
167 | "Display the current IELM working buffer. | |
168 | Don't forget that selecting that buffer will change its value of `point' | |
169 | to its value of `window-point'!" | |
170 | (interactive) | |
171 | (display-buffer ielm-working-buffer) | |
172 | (ielm-print-working-buffer)) | |
173 | ||
174 | (defun ielm-change-working-buffer (buf) | |
175 | "Change the current IELM working buffer to BUF. | |
176 | This is the buffer in which all sexps entered at the IELM prompt are | |
177 | evaluated. You can achieve the same effect with a call to | |
178 | `set-buffer' at the IELM prompt." | |
179 | (interactive "bSet working buffer to: ") | |
180 | (setq ielm-working-buffer (or (get-buffer buf) (error "No such buffer"))) | |
181 | (ielm-print-working-buffer)) | |
182 | ||
813f532d RS |
183 | ;;; Other bindings |
184 | ||
185 | (defun ielm-return nil | |
e848854a RS |
186 | "Newline and indent, or evaluate the sexp before the prompt. |
187 | Complete sexps are evaluated; for incomplete sexps inserts a newline | |
188 | and indents. If however `ielm-dynamic-return' is nil, this always | |
189 | simply inserts a newline." | |
813f532d RS |
190 | (interactive) |
191 | (if ielm-dynamic-return | |
192 | (let ((state | |
193 | (save-excursion | |
194 | (end-of-line) | |
195 | (parse-partial-sexp (ielm-pm) | |
196 | (point))))) | |
197 | (if (and (< (car state) 1) (not (nth 3 state))) | |
198 | (ielm-send-input) | |
e848854a RS |
199 | (if (and ielm-dynamic-multiline-inputs |
200 | (save-excursion | |
201 | (beginning-of-line) | |
202 | (looking-at comint-prompt-regexp))) | |
203 | (save-excursion | |
204 | (goto-char (ielm-pm)) | |
205 | (newline 1))) | |
813f532d RS |
206 | (newline-and-indent))) |
207 | (newline))) | |
208 | ||
209 | (defun ielm-input-sender (proc input) | |
e848854a RS |
210 | ;; Just sets the variable ielm-input, which is in the scope of |
211 | ;; `ielm-send-input's call. | |
813f532d RS |
212 | (setq ielm-input input)) |
213 | ||
214 | (defun ielm-send-input nil | |
e848854a | 215 | "Evaluate the Emacs Lisp expression after the prompt." |
813f532d RS |
216 | (interactive) |
217 | (let ((buf (current-buffer)) | |
218 | ielm-input) ; set by ielm-input-sender | |
219 | (comint-send-input) ; update history, markers etc. | |
220 | (ielm-eval-input ielm-input))) | |
221 | ||
222 | ;;; Utility functions | |
223 | ||
224 | (defun ielm-is-whitespace (string) | |
e848854a | 225 | "Return non-nil if STRING is all whitespace." |
813f532d RS |
226 | (or (string= string "") (string-match "\\`[ \t\n]+\\'" string))) |
227 | ||
228 | (defun ielm-format-errors (errlist) | |
229 | (let ((result "")) | |
230 | (while errlist | |
231 | (setq result (concat result (prin1-to-string (car errlist)) ", ")) | |
232 | (setq errlist (cdr errlist))) | |
233 | (substring result 0 -2))) | |
234 | ||
235 | ||
236 | (defun ielm-format-error (err) | |
e848854a | 237 | ;; Return a string form of the error ERR. |
813f532d RS |
238 | (format "%s%s" |
239 | (or (get (car err) 'error-message) "Peculiar error") | |
240 | (if (cdr err) | |
241 | (format ": %s" (ielm-format-errors (cdr err))) | |
242 | ""))) | |
243 | ||
244 | ;;; Evaluation | |
245 | ||
e848854a RS |
246 | (defun ielm-eval-input (ielm-string) |
247 | "Evaluate the Lisp expression IELM-STRING, and pretty-print the result." | |
813f532d | 248 | ;; This is the function that actually `sends' the input to the |
e848854a | 249 | ;; `inferior Lisp process'. All comint-send-input does is works out |
813f532d RS |
250 | ;; what that input is. What this function does is evaluates that |
251 | ;; input and produces `output' which gets inserted into the buffer, | |
252 | ;; along with a new prompt. A better way of doing this might have | |
253 | ;; been to actually send the output to the `cat' process, and write | |
254 | ;; this as in output filter that converted sexps in the output | |
255 | ;; stream to their evaluated value. But that would have involved | |
256 | ;; more process coordination than I was happy to deal with. | |
e848854a RS |
257 | ;; |
258 | ;; NOTE: all temporary variables in this function will be in scope | |
259 | ;; during the eval, and so need to have non-clashing names. | |
260 | (let (ielm-form ; form to evaluate | |
261 | ielm-pos ; End posn of parse in string | |
262 | ielm-result ; Result, or error message | |
263 | ielm-error-type ; string, nil if no error | |
264 | (ielm-output "") ; result to display | |
265 | (ielm-wbuf ielm-working-buffer) ; current buffer after evaluation | |
266 | (ielm-pmark (ielm-pm))) | |
267 | (if (not (ielm-is-whitespace ielm-string)) | |
813f532d RS |
268 | (progn |
269 | (condition-case err | |
270 | (let (rout) | |
e848854a RS |
271 | (setq rout (read-from-string ielm-string)) |
272 | (setq ielm-form (car rout)) | |
273 | (setq ielm-pos (cdr rout))) | |
274 | (error (setq ielm-result (ielm-format-error err)) | |
275 | (setq ielm-error-type "Read error"))) | |
276 | (if ielm-error-type nil | |
277 | ;; Make sure working buffer has not been killed | |
278 | (if (not (buffer-name ielm-working-buffer)) | |
279 | (setq ielm-result "Working buffer has been killed" | |
280 | ielm-error-type "IELM Error" | |
281 | ielm-wbuf (current-buffer)) | |
282 | (if (ielm-is-whitespace (substring ielm-string ielm-pos)) | |
283 | ;; need this awful let convolution to work around | |
284 | ;; an Emacs bug involving local vbls and let binding | |
285 | (let ((:save :) | |
286 | (::save ::) | |
287 | (:::save :::)) | |
288 | (save-excursion | |
289 | (set-buffer ielm-working-buffer) | |
290 | (condition-case err | |
291 | (let ((: :save) | |
292 | (:: ::save) | |
293 | (::: :::save) | |
294 | (ielm-obuf (current-buffer))) | |
295 | (setq ielm-result (eval ielm-form)) | |
296 | (setq ielm-wbuf (current-buffer)) | |
297 | ;; The eval may have changed current-buffer; | |
298 | ;; need to set it back here to avoid a bug | |
299 | ;; in let. Don't want to use save-excursion | |
300 | ;; because we want to allow changes in point. | |
301 | (set-buffer ielm-obuf)) | |
302 | (error (setq ielm-result (ielm-format-error err)) | |
303 | (setq ielm-error-type "Eval error")) | |
304 | (quit (setq ielm-result "Quit during evaluation") | |
305 | (setq ielm-error-type "Eval error"))))) | |
306 | (setq ielm-error-type "IELM error") | |
307 | (setq ielm-result "More than one sexp in input")))) | |
813f532d RS |
308 | |
309 | ;; If the eval changed the current buffer, mention it here | |
e848854a RS |
310 | (if (eq ielm-wbuf ielm-working-buffer) nil |
311 | (message "current buffer is now: %s" ielm-wbuf) | |
312 | (setq ielm-working-buffer ielm-wbuf)) | |
813f532d | 313 | |
e848854a RS |
314 | (goto-char ielm-pmark) |
315 | (if (not ielm-error-type) | |
813f532d RS |
316 | (condition-case err |
317 | ;; Self-referential objects cause loops in the printer, so | |
318 | ;; trap quits here. May as well do errors, too | |
e848854a RS |
319 | (setq ielm-output (concat ielm-output (pp-to-string ielm-result))) |
320 | (error (setq ielm-error-type "IELM Error") | |
321 | (setq ielm-result "Error during pretty-printing (bug in pp)")) | |
322 | (quit (setq ielm-error-type "IELM Error") | |
323 | (setq ielm-result "Quit during pretty-printing")))) | |
324 | (if ielm-error-type | |
813f532d RS |
325 | (progn |
326 | (if ielm-noisy (ding)) | |
e848854a RS |
327 | (setq ielm-output (concat ielm-output "*** " ielm-error-type " *** ")) |
328 | (setq ielm-output (concat ielm-output ielm-result))) | |
813f532d RS |
329 | ;; There was no error, so shift the ::: values |
330 | (setq ::: ::) | |
331 | (setq :: :) | |
e848854a RS |
332 | (setq : ielm-result)) |
333 | (setq ielm-output (concat ielm-output "\n")))) | |
334 | (setq ielm-output (concat ielm-output ielm-prompt)) | |
335 | (comint-output-filter (ielm-process) ielm-output))) | |
813f532d RS |
336 | |
337 | ;;; Process and marker utilities | |
338 | ||
339 | (defun ielm-process nil | |
e848854a | 340 | ;; Return the current buffer's process. |
813f532d RS |
341 | (get-buffer-process (current-buffer))) |
342 | ||
343 | (defun ielm-pm nil | |
e848854a | 344 | ;; Return the process mark of the current buffer. |
813f532d RS |
345 | (process-mark (get-buffer-process (current-buffer)))) |
346 | ||
347 | (defun ielm-set-pm (pos) | |
e848854a | 348 | ;; Set the process mark in the current buffer to POS. |
813f532d RS |
349 | (set-marker (process-mark (get-buffer-process (current-buffer))) pos)) |
350 | ||
351 | ;;; Major mode | |
352 | ||
353 | (defun inferior-emacs-lisp-mode nil | |
e848854a RS |
354 | "Major mode for interactively evaluating Emacs Lisp expressions. |
355 | Uses the interface provided by `comint-mode' (which see). | |
356 | ||
357 | * \\<ielm-map>\\[ielm-send-input] evaluates the sexp following the prompt. There must be at most | |
358 | one top-level sexp per prompt. | |
813f532d | 359 | |
e848854a RS |
360 | * \\[ielm-return] inserts a newline and indents, or evaluates a |
361 | complete expression (but see variable `ielm-dynamic-return'). | |
362 | Inputs longer than one line are moved to the line following the | |
363 | prompt (but see variable `ielm-dynamic-multiline-inputs'). | |
364 | ||
365 | * \\[comint-dynamic-complete] completes Lisp symbols (or filenames, within strings), | |
366 | or indents the line if there is nothing to complete. | |
813f532d RS |
367 | |
368 | During evaluations, the values of the variables `:', `::', and `:::' | |
369 | are the results of the previous, second previous and third previous | |
370 | evaluations respectively. | |
371 | ||
e848854a RS |
372 | The current working buffer may be changed (with a call to |
373 | `set-buffer', or with \\[ielm-change-working-buffer]), and its value | |
374 | is preserved between successive evaluations. In this way, expressions | |
375 | may be evaluated in a different buffer than the *ielm* buffer. | |
376 | Display the name of the working buffer with \\[ielm-print-working-buffer], | |
377 | or the buffer itself with \\[ielm-display-working-buffer]. | |
813f532d | 378 | |
e848854a RS |
379 | Expressions evaluated by IELM are not subject to `debug-on-quit' or |
380 | `debug-on-error'. | |
813f532d RS |
381 | |
382 | The behaviour of IELM may be customised with the following variables: | |
383 | * To stop beeping on error, set `ielm-noisy' to nil | |
384 | * If you don't like the prompt, you can change it by setting `ielm-prompt'. | |
385 | * Set `ielm-dynamic-return' to nil for bindings like `lisp-interaction-mode' | |
386 | * Entry to this mode runs `comint-mode-hook' and `ielm-mode-hook' | |
387 | (in that order). | |
388 | ||
389 | Customised bindings may be defined in `ielm-map', which currently contains: | |
390 | \\{ielm-map}" | |
391 | (interactive) | |
392 | (comint-mode) | |
393 | (setq comint-prompt-regexp (concat "^" (regexp-quote ielm-prompt))) | |
394 | (make-local-variable 'paragraph-start) | |
395 | (setq paragraph-start comint-prompt-regexp) | |
396 | (setq comint-input-sender 'ielm-input-sender) | |
397 | (setq comint-process-echoes nil) | |
398 | (setq comint-dynamic-complete-functions | |
399 | '(ielm-tab comint-replace-by-expanded-history ielm-complete-filename ielm-complete-symbol)) | |
e848854a | 400 | (setq comint-get-old-input 'ielm-get-old-input) |
813f532d RS |
401 | |
402 | (setq major-mode 'inferior-emacs-lisp-mode) | |
403 | (setq mode-name "IELM") | |
404 | (use-local-map ielm-map) | |
405 | (set-syntax-table emacs-lisp-mode-syntax-table) | |
406 | ||
407 | (make-local-variable 'indent-line-function) | |
408 | (make-local-variable 'ielm-working-buffer) | |
409 | (setq ielm-working-buffer (current-buffer)) | |
410 | (setq indent-line-function 'ielm-indent-line) | |
411 | ||
e848854a | 412 | ;; Value holders |
813f532d RS |
413 | (setq : nil) |
414 | (make-local-variable ':) | |
415 | (setq :: nil) | |
416 | (make-local-variable '::) | |
417 | (setq ::: nil) | |
418 | (make-local-variable ':::) | |
419 | ||
420 | ;; A dummy process to keep comint happy. It will never get any input | |
421 | (if (comint-check-proc (current-buffer)) nil | |
422 | (start-process "ielm" (current-buffer) "cat") | |
423 | (process-kill-without-query (ielm-process)) | |
424 | (goto-char (point-max)) | |
425 | ;; Add a silly header | |
426 | (insert ielm-header) | |
427 | (ielm-set-pm (point-max)) | |
428 | (comint-output-filter (ielm-process) ielm-prompt) | |
429 | (set-marker comint-last-input-start (ielm-pm)) | |
430 | (set-process-filter (get-buffer-process (current-buffer)) 'comint-output-filter)) | |
431 | (run-hooks 'ielm-mode-hook)) | |
432 | ||
e848854a RS |
433 | (defun ielm-get-old-input nil |
434 | ;; Return the previous input surrounding point | |
435 | (save-excursion | |
436 | (beginning-of-line) | |
437 | (if (looking-at comint-prompt-regexp) nil | |
438 | (re-search-backward comint-prompt-regexp)) | |
439 | (comint-skip-prompt) | |
440 | (buffer-substring (point) (progn (forward-sexp 1) (point))))) | |
441 | ||
813f532d RS |
442 | ;;; User command |
443 | ||
9e983c78 RS |
444 | ;;;###autoload (add-hook 'same-window-buffer-names "*ielm*") |
445 | ||
e848854a | 446 | ;;;###autoload |
813f532d | 447 | (defun ielm nil |
e848854a | 448 | "Interactively evaluate Emacs Lisp expressions. |
9e983c78 | 449 | Switches to the buffer `*ielm*', or creates it if it does not exist." |
813f532d | 450 | (interactive) |
9e983c78 RS |
451 | (if (comint-check-proc "*ielm*") |
452 | nil | |
453 | (save-excursion | |
813f532d RS |
454 | (set-buffer (get-buffer-create "*ielm*")) |
455 | (inferior-emacs-lisp-mode))) | |
9e983c78 | 456 | (pop-to-buffer "*ielm*")) |
813f532d | 457 | |
e848854a | 458 | ;;; ielm.el ends here |