| 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 | |
| 26 | ;; Provides a nice interface to evaluating Emacs Lisp expressions. |
| 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 |
| 31 | ;; add the following line to your .emacs file: |
| 32 | ;; |
| 33 | ;; (autoload 'ielm "ielm" "Start an inferior Emacs Lisp session" t) |
| 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 |
| 61 | "*If non-nil, IELM will beep on error.") |
| 62 | |
| 63 | (defvar ielm-prompt "ELISP> " |
| 64 | "Prompt used in IELM.") |
| 65 | |
| 66 | (defvar ielm-dynamic-return t |
| 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.") |
| 77 | |
| 78 | (defvar ielm-mode-hook nil |
| 79 | "*Hooks to be run when IELM (`inferior-emacs-lisp-mode') is started.") |
| 80 | |
| 81 | ;;; System variables |
| 82 | |
| 83 | (defvar ielm-working-buffer nil |
| 84 | "Buffer in which IELM sexps will be evaluated. |
| 85 | This variable is buffer-local.") |
| 86 | |
| 87 | (defvar ielm-header |
| 88 | (concat |
| 89 | "*** Welcome to IELM version " |
| 90 | (substring "$Revision: 1.3 $" 11 -2) |
| 91 | " *** Type (describe-mode) for help.\n" |
| 92 | "IELM has ABSOLUTELY NO WARRANTY; type (describe-no-warranty) for details.\n") |
| 93 | "Message to display when IELM is started.") |
| 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) |
| 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)) |
| 118 | |
| 119 | ;;; Completion stuff |
| 120 | |
| 121 | (defun ielm-tab nil |
| 122 | "Possibly indent the current line as lisp code." |
| 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 |
| 131 | "Complete the lisp symbol before point." |
| 132 | ;; A wrapper for lisp-complete symbol that returns non-nil if |
| 133 | ;; completion has occurred |
| 134 | (let* ((btick (buffer-modified-tick)) |
| 135 | (cbuffer (get-buffer "*Completions*")) |
| 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))) |
| 145 | (get-buffer "*Completions*"))))) |
| 146 | |
| 147 | (defun ielm-complete-filename nil |
| 148 | "Dynamically complete filename before point, if in a string." |
| 149 | (if (nth 3 (parse-partial-sexp comint-last-input-start (point))) |
| 150 | (comint-dynamic-complete-filename))) |
| 151 | |
| 152 | (defun ielm-indent-line nil |
| 153 | "Indent the current line as Lisp code if it is not a prompt line." |
| 154 | (if (save-excursion |
| 155 | (beginning-of-line) |
| 156 | (looking-at comint-prompt-regexp)) nil |
| 157 | (lisp-indent-line))) |
| 158 | |
| 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 | |
| 183 | ;;; Other bindings |
| 184 | |
| 185 | (defun ielm-return nil |
| 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." |
| 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) |
| 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))) |
| 206 | (newline-and-indent))) |
| 207 | (newline))) |
| 208 | |
| 209 | (defun ielm-input-sender (proc input) |
| 210 | ;; Just sets the variable ielm-input, which is in the scope of |
| 211 | ;; `ielm-send-input's call. |
| 212 | (setq ielm-input input)) |
| 213 | |
| 214 | (defun ielm-send-input nil |
| 215 | "Evaluate the Emacs Lisp expression after the prompt." |
| 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) |
| 225 | "Return non-nil if STRING is all whitespace." |
| 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) |
| 237 | ;; Return a string form of the error ERR. |
| 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 | |
| 246 | (defun ielm-eval-input (ielm-string) |
| 247 | "Evaluate the Lisp expression IELM-STRING, and pretty-print the result." |
| 248 | ;; This is the function that actually `sends' the input to the |
| 249 | ;; `inferior Lisp process'. All comint-send-input does is works out |
| 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. |
| 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)) |
| 268 | (progn |
| 269 | (condition-case err |
| 270 | (let (rout) |
| 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")))) |
| 308 | |
| 309 | ;; If the eval changed the current buffer, mention it here |
| 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)) |
| 313 | |
| 314 | (goto-char ielm-pmark) |
| 315 | (if (not ielm-error-type) |
| 316 | (condition-case err |
| 317 | ;; Self-referential objects cause loops in the printer, so |
| 318 | ;; trap quits here. May as well do errors, too |
| 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 |
| 325 | (progn |
| 326 | (if ielm-noisy (ding)) |
| 327 | (setq ielm-output (concat ielm-output "*** " ielm-error-type " *** ")) |
| 328 | (setq ielm-output (concat ielm-output ielm-result))) |
| 329 | ;; There was no error, so shift the ::: values |
| 330 | (setq ::: ::) |
| 331 | (setq :: :) |
| 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))) |
| 336 | |
| 337 | ;;; Process and marker utilities |
| 338 | |
| 339 | (defun ielm-process nil |
| 340 | ;; Return the current buffer's process. |
| 341 | (get-buffer-process (current-buffer))) |
| 342 | |
| 343 | (defun ielm-pm nil |
| 344 | ;; Return the process mark of the current buffer. |
| 345 | (process-mark (get-buffer-process (current-buffer)))) |
| 346 | |
| 347 | (defun ielm-set-pm (pos) |
| 348 | ;; Set the process mark in the current buffer to POS. |
| 349 | (set-marker (process-mark (get-buffer-process (current-buffer))) pos)) |
| 350 | |
| 351 | ;;; Major mode |
| 352 | |
| 353 | (defun inferior-emacs-lisp-mode nil |
| 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. |
| 359 | |
| 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. |
| 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 | |
| 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]. |
| 378 | |
| 379 | Expressions evaluated by IELM are not subject to `debug-on-quit' or |
| 380 | `debug-on-error'. |
| 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)) |
| 400 | (setq comint-get-old-input 'ielm-get-old-input) |
| 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 | |
| 412 | ;; Value holders |
| 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 | |
| 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 | |
| 442 | ;;; User command |
| 443 | |
| 444 | ;;;###autoload (add-hook 'same-window-buffer-names "*ielm*") |
| 445 | |
| 446 | ;;;###autoload |
| 447 | (defun ielm nil |
| 448 | "Interactively evaluate Emacs Lisp expressions. |
| 449 | Switches to the buffer `*ielm*', or creates it if it does not exist." |
| 450 | (interactive) |
| 451 | (if (comint-check-proc "*ielm*") |
| 452 | nil |
| 453 | (save-excursion |
| 454 | (set-buffer (get-buffer-create "*ielm*")) |
| 455 | (inferior-emacs-lisp-mode))) |
| 456 | (pop-to-buffer "*ielm*")) |
| 457 | |
| 458 | ;;; ielm.el ends here |