| 1 | ;;; -*- lexical-binding: t -*- |
| 2 | ;;; ielm.el --- interaction mode for Emacs Lisp |
| 3 | |
| 4 | ;; Copyright (C) 1994, 2001-2014 Free Software Foundation, Inc. |
| 5 | |
| 6 | ;; Author: David Smith <maa036@lancaster.ac.uk> |
| 7 | ;; Maintainer: emacs-devel@gnu.org |
| 8 | ;; Created: 25 Feb 1994 |
| 9 | ;; Keywords: lisp |
| 10 | |
| 11 | ;; This file is part of GNU Emacs. |
| 12 | |
| 13 | ;; GNU Emacs is free software: you can redistribute it and/or modify |
| 14 | ;; it under the terms of the GNU General Public License as published by |
| 15 | ;; the Free Software Foundation, either version 3 of the License, or |
| 16 | ;; (at your option) any later version. |
| 17 | |
| 18 | ;; GNU Emacs is distributed in the hope that it will be useful, |
| 19 | ;; but WITHOUT ANY WARRANTY; without even the implied warranty of |
| 20 | ;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| 21 | ;; GNU General Public License for more details. |
| 22 | |
| 23 | ;; You should have received a copy of the GNU General Public License |
| 24 | ;; along with GNU Emacs. If not, see <http://www.gnu.org/licenses/>. |
| 25 | |
| 26 | ;;; Commentary: |
| 27 | |
| 28 | ;; Provides a nice interface to evaluating Emacs Lisp expressions. |
| 29 | ;; Input is handled by the comint package, and output is passed |
| 30 | ;; through the pretty-printer. |
| 31 | |
| 32 | ;; To start: M-x ielm. Type C-h m in the *ielm* buffer for more info. |
| 33 | |
| 34 | ;;; Code: |
| 35 | |
| 36 | (require 'comint) |
| 37 | (require 'pp) |
| 38 | |
| 39 | ;;; User variables |
| 40 | |
| 41 | (defgroup ielm nil |
| 42 | "Interaction mode for Emacs Lisp." |
| 43 | :group 'lisp) |
| 44 | |
| 45 | |
| 46 | (defcustom ielm-noisy t |
| 47 | "If non-nil, IELM will beep on error." |
| 48 | :type 'boolean |
| 49 | :group 'ielm) |
| 50 | |
| 51 | (defcustom ielm-prompt-read-only t |
| 52 | "If non-nil, the IELM prompt is read only. |
| 53 | The read only region includes the newline before the prompt. |
| 54 | Setting this variable does not affect existing IELM runs. |
| 55 | This works by setting the buffer-local value of `comint-prompt-read-only'. |
| 56 | Setting that value directly affects new prompts in the current buffer. |
| 57 | |
| 58 | If this option is enabled, then the safe way to temporarily |
| 59 | override the read-only-ness of IELM prompts is to call |
| 60 | `comint-kill-whole-line' or `comint-kill-region' with no |
| 61 | narrowing in effect. This way you will be certain that none of |
| 62 | the remaining prompts will be accidentally messed up. You may |
| 63 | wish to put something like the following in your init file: |
| 64 | |
| 65 | \(add-hook 'ielm-mode-hook |
| 66 | (lambda () |
| 67 | (define-key ielm-map \"\\C-w\" 'comint-kill-region) |
| 68 | (define-key ielm-map [C-S-backspace] |
| 69 | 'comint-kill-whole-line))) |
| 70 | |
| 71 | If you set `comint-prompt-read-only' to t, you might wish to use |
| 72 | `comint-mode-hook' and `comint-mode-map' instead of |
| 73 | `ielm-mode-hook' and `ielm-map'. That will affect all comint |
| 74 | buffers, including IELM buffers. If you sometimes use IELM on |
| 75 | text-only terminals or with `emacs -nw', you might wish to use |
| 76 | another binding for `comint-kill-whole-line'." |
| 77 | :type 'boolean |
| 78 | :group 'ielm |
| 79 | :version "22.1") |
| 80 | |
| 81 | (defcustom ielm-prompt "ELISP> " |
| 82 | "Prompt used in IELM. |
| 83 | Setting this variable does not affect existing IELM runs. |
| 84 | |
| 85 | Interrupting the IELM process with \\<ielm-map>\\[comint-interrupt-subjob], |
| 86 | and then restarting it using \\[ielm], makes the then current |
| 87 | default value affect _new_ prompts. Unless the new prompt |
| 88 | differs only in text properties from the old one, IELM will no |
| 89 | longer recognize the old prompts. However, executing \\[ielm] |
| 90 | does not update the prompt of an *ielm* buffer with a running process. |
| 91 | For IELM buffers that are not called `*ielm*', you can execute |
| 92 | \\[inferior-emacs-lisp-mode] in that IELM buffer to update the value, |
| 93 | for new prompts. This works even if the buffer has a running process." |
| 94 | :type 'string |
| 95 | :group 'ielm) |
| 96 | |
| 97 | (defvar ielm-prompt-internal "ELISP> " |
| 98 | "Stored value of `ielm-prompt' in the current IELM buffer. |
| 99 | This is an internal variable used by IELM. Its purpose is to |
| 100 | prevent a running IELM process from being messed up when the user |
| 101 | customizes `ielm-prompt'.") |
| 102 | |
| 103 | (defcustom ielm-dynamic-return t |
| 104 | "Controls whether \\<ielm-map>\\[ielm-return] has intelligent behavior in IELM. |
| 105 | If non-nil, \\[ielm-return] evaluates input for complete sexps, or inserts a newline |
| 106 | and indents for incomplete sexps. If nil, always inserts newlines." |
| 107 | :type 'boolean |
| 108 | :group 'ielm) |
| 109 | |
| 110 | (defcustom ielm-dynamic-multiline-inputs t |
| 111 | "Force multiline inputs to start from column zero? |
| 112 | If non-nil, after entering the first line of an incomplete sexp, a newline |
| 113 | will be inserted after the prompt, moving the input to the next line. |
| 114 | This gives more frame width for large indented sexps, and allows functions |
| 115 | such as `edebug-defun' to work with such inputs." |
| 116 | :type 'boolean |
| 117 | :group 'ielm) |
| 118 | |
| 119 | (defcustom ielm-mode-hook nil |
| 120 | "Hooks to be run when IELM (`inferior-emacs-lisp-mode') is started." |
| 121 | :options '(eldoc-mode) |
| 122 | :type 'hook |
| 123 | :group 'ielm) |
| 124 | (defvaralias 'inferior-emacs-lisp-mode-hook 'ielm-mode-hook) |
| 125 | |
| 126 | (defvar * nil |
| 127 | "Most recent value evaluated in IELM.") |
| 128 | |
| 129 | (defvar ** nil |
| 130 | "Second-most-recent value evaluated in IELM.") |
| 131 | |
| 132 | (defvar *** nil |
| 133 | "Third-most-recent value evaluated in IELM.") |
| 134 | |
| 135 | (defvar ielm-match-data nil |
| 136 | "Match data saved at the end of last command.") |
| 137 | |
| 138 | (defvar *1 nil |
| 139 | "During IELM evaluation, most recent value evaluated in IELM. |
| 140 | Normally identical to `*'. However, if the working buffer is an IELM |
| 141 | buffer, distinct from the process buffer, then `*' gives the value in |
| 142 | the working buffer, `*1' the value in the process buffer. |
| 143 | The intended value is only accessible during IELM evaluation.") |
| 144 | |
| 145 | (defvar *2 nil |
| 146 | "During IELM evaluation, second-most-recent value evaluated in IELM. |
| 147 | Normally identical to `**'. However, if the working buffer is an IELM |
| 148 | buffer, distinct from the process buffer, then `**' gives the value in |
| 149 | the working buffer, `*2' the value in the process buffer. |
| 150 | The intended value is only accessible during IELM evaluation.") |
| 151 | |
| 152 | (defvar *3 nil |
| 153 | "During IELM evaluation, third-most-recent value evaluated in IELM. |
| 154 | Normally identical to `***'. However, if the working buffer is an IELM |
| 155 | buffer, distinct from the process buffer, then `***' gives the value in |
| 156 | the working buffer, `*3' the value in the process buffer. |
| 157 | The intended value is only accessible during IELM evaluation.") |
| 158 | |
| 159 | ;;; System variables |
| 160 | |
| 161 | (defvar ielm-working-buffer nil |
| 162 | "Buffer in which IELM sexps will be evaluated. |
| 163 | This variable is buffer-local.") |
| 164 | |
| 165 | (defvar ielm-header |
| 166 | "*** Welcome to IELM *** Type (describe-mode) for help.\n" |
| 167 | "Message to display when IELM is started.") |
| 168 | |
| 169 | (defvar ielm-map |
| 170 | (let ((map (make-sparse-keymap))) |
| 171 | (define-key map "\t" 'ielm-tab) |
| 172 | (define-key map "\C-m" 'ielm-return) |
| 173 | (define-key map "\e\C-m" 'ielm-return-for-effect) |
| 174 | (define-key map "\C-j" 'ielm-send-input) |
| 175 | (define-key map "\e\C-x" 'eval-defun) ; for consistency with |
| 176 | (define-key map "\e\t" 'completion-at-point) ; lisp-interaction-mode |
| 177 | ;; These bindings are from `lisp-mode-shared-map' -- can you inherit |
| 178 | ;; from more than one keymap?? |
| 179 | (define-key map "\e\C-q" 'indent-sexp) |
| 180 | (define-key map "\177" 'backward-delete-char-untabify) |
| 181 | ;; Some convenience bindings for setting the working buffer |
| 182 | (define-key map "\C-c\C-b" 'ielm-change-working-buffer) |
| 183 | (define-key map "\C-c\C-f" 'ielm-display-working-buffer) |
| 184 | (define-key map "\C-c\C-v" 'ielm-print-working-buffer) |
| 185 | map) |
| 186 | "Keymap for IELM mode.") |
| 187 | (defvaralias 'inferior-emacs-lisp-mode-map 'ielm-map) |
| 188 | |
| 189 | (easy-menu-define ielm-menu ielm-map |
| 190 | "IELM mode menu." |
| 191 | '("IELM" |
| 192 | ["Change Working Buffer" ielm-change-working-buffer t] |
| 193 | ["Display Working Buffer" ielm-display-working-buffer t] |
| 194 | ["Print Working Buffer" ielm-print-working-buffer t])) |
| 195 | |
| 196 | (defvar ielm-font-lock-keywords |
| 197 | '(("\\(^\\*\\*\\*[^*]+\\*\\*\\*\\)\\(.*$\\)" |
| 198 | (1 font-lock-comment-face) |
| 199 | (2 font-lock-constant-face))) |
| 200 | "Additional expressions to highlight in IELM buffers.") |
| 201 | |
| 202 | ;;; Completion stuff |
| 203 | |
| 204 | (defun ielm-tab () |
| 205 | "Indent or complete." |
| 206 | (interactive) |
| 207 | (if (or (eq (preceding-char) ?\n) |
| 208 | (eq (char-syntax (preceding-char)) ?\s)) |
| 209 | (ielm-indent-line) |
| 210 | (completion-at-point))) |
| 211 | |
| 212 | |
| 213 | (defun ielm-complete-filename nil |
| 214 | "Dynamically complete filename before point, if in a string." |
| 215 | (when (nth 3 (parse-partial-sexp comint-last-input-start (point))) |
| 216 | (comint-filename-completion))) |
| 217 | |
| 218 | (defun ielm-indent-line nil |
| 219 | "Indent the current line as Lisp code if it is not a prompt line." |
| 220 | (when (save-excursion (comint-bol) (bolp)) |
| 221 | (lisp-indent-line))) |
| 222 | |
| 223 | ;;; Working buffer manipulation |
| 224 | |
| 225 | (defun ielm-print-working-buffer nil |
| 226 | "Print the current IELM working buffer's name in the echo area." |
| 227 | (interactive) |
| 228 | (message "The current working buffer is: %s" (buffer-name ielm-working-buffer))) |
| 229 | |
| 230 | (defun ielm-display-working-buffer nil |
| 231 | "Display the current IELM working buffer. |
| 232 | Don't forget that selecting that buffer will change its value of `point' |
| 233 | to its value of `window-point'!" |
| 234 | (interactive) |
| 235 | (display-buffer ielm-working-buffer) |
| 236 | (ielm-print-working-buffer)) |
| 237 | |
| 238 | (defun ielm-change-working-buffer (buf) |
| 239 | "Change the current IELM working buffer to BUF. |
| 240 | This is the buffer in which all sexps entered at the IELM prompt are |
| 241 | evaluated. You can achieve the same effect with a call to |
| 242 | `set-buffer' at the IELM prompt." |
| 243 | (interactive "bSet working buffer to: ") |
| 244 | (let ((buffer (get-buffer buf))) |
| 245 | (if (and buffer (buffer-live-p buffer)) |
| 246 | (setq ielm-working-buffer buffer) |
| 247 | (error "No such buffer: %S" buf))) |
| 248 | (ielm-print-working-buffer)) |
| 249 | |
| 250 | ;;; Other bindings |
| 251 | |
| 252 | (defun ielm-return (&optional for-effect) |
| 253 | "Newline and indent, or evaluate the sexp before the prompt. |
| 254 | Complete sexps are evaluated; for incomplete sexps inserts a newline |
| 255 | and indents. If however `ielm-dynamic-return' is nil, this always |
| 256 | simply inserts a newline." |
| 257 | (interactive) |
| 258 | (if ielm-dynamic-return |
| 259 | (let ((state |
| 260 | (save-excursion |
| 261 | (end-of-line) |
| 262 | (parse-partial-sexp (ielm-pm) |
| 263 | (point))))) |
| 264 | (if (and (< (car state) 1) (not (nth 3 state))) |
| 265 | (ielm-send-input for-effect) |
| 266 | (when (and ielm-dynamic-multiline-inputs |
| 267 | (save-excursion |
| 268 | (beginning-of-line) |
| 269 | (looking-at-p comint-prompt-regexp))) |
| 270 | (save-excursion |
| 271 | (goto-char (ielm-pm)) |
| 272 | (newline 1))) |
| 273 | (newline-and-indent))) |
| 274 | (newline))) |
| 275 | |
| 276 | (defun ielm-return-for-effect () |
| 277 | "Like `ielm-return', but do not print the result." |
| 278 | (interactive) |
| 279 | (ielm-return t)) |
| 280 | |
| 281 | (defvar ielm-input) |
| 282 | |
| 283 | (defun ielm-input-sender (_proc input) |
| 284 | ;; Just sets the variable ielm-input, which is in the scope of |
| 285 | ;; `ielm-send-input's call. |
| 286 | (setq ielm-input input)) |
| 287 | |
| 288 | (defun ielm-send-input (&optional for-effect) |
| 289 | "Evaluate the Emacs Lisp expression after the prompt." |
| 290 | (interactive) |
| 291 | (let (ielm-input) ; set by ielm-input-sender |
| 292 | (comint-send-input) ; update history, markers etc. |
| 293 | (ielm-eval-input ielm-input for-effect))) |
| 294 | |
| 295 | ;;; Utility functions |
| 296 | |
| 297 | (defun ielm-is-whitespace-or-comment (string) |
| 298 | "Return non-nil if STRING is all whitespace or a comment." |
| 299 | (or (string= string "") |
| 300 | (string-match-p "\\`[ \t\n]*\\(?:;.*\\)*\\'" string))) |
| 301 | |
| 302 | ;;; Evaluation |
| 303 | |
| 304 | (defun ielm-standard-output-impl (process) |
| 305 | "Return a function to use for `standard-output' while in ielm eval. |
| 306 | The returned function takes one character as input. Passing nil |
| 307 | to this function instead of a character flushes the output |
| 308 | buffer. Passing t appends a terminating newline if the buffer is |
| 309 | nonempty, then flushes the buffer." |
| 310 | ;; Use an intermediate output buffer because doing redisplay for |
| 311 | ;; each character we output is too expensive. Set up a flush timer |
| 312 | ;; so that users don't have to wait for whole lines to appear before |
| 313 | ;; seeing output. |
| 314 | (let* ((output-buffer nil) |
| 315 | (flush-timer nil) |
| 316 | (flush-buffer |
| 317 | (lambda () |
| 318 | (comint-output-filter |
| 319 | process |
| 320 | (apply #'string (nreverse output-buffer))) |
| 321 | (redisplay) |
| 322 | (setf output-buffer nil) |
| 323 | (when flush-timer |
| 324 | (cancel-timer flush-timer) |
| 325 | (setf flush-timer nil))))) |
| 326 | (lambda (char) |
| 327 | (let (flush-now) |
| 328 | (cond ((and (eq char t) output-buffer) |
| 329 | (push ?\n output-buffer) |
| 330 | (setf flush-now t)) |
| 331 | ((characterp char) |
| 332 | (push char output-buffer))) |
| 333 | (if flush-now |
| 334 | (funcall flush-buffer) |
| 335 | (unless flush-timer |
| 336 | (setf flush-timer (run-with-timer 0.1 nil flush-buffer)))))))) |
| 337 | |
| 338 | (defun ielm-eval-input (input-string &optional for-effect) |
| 339 | "Evaluate the Lisp expression INPUT-STRING, and pretty-print the result." |
| 340 | ;; This is the function that actually `sends' the input to the |
| 341 | ;; `inferior Lisp process'. All comint-send-input does is works out |
| 342 | ;; what that input is. What this function does is evaluates that |
| 343 | ;; input and produces `output' which gets inserted into the buffer, |
| 344 | ;; along with a new prompt. A better way of doing this might have |
| 345 | ;; been to actually send the output to the `cat' process, and write |
| 346 | ;; this as in output filter that converted sexps in the output |
| 347 | ;; stream to their evaluated value. But that would have involved |
| 348 | ;; more process coordination than I was happy to deal with. |
| 349 | (let ((string input-string) ; input expression, as a string |
| 350 | form ; form to evaluate |
| 351 | pos ; End posn of parse in string |
| 352 | result ; Result, or error message |
| 353 | error-type ; string, nil if no error |
| 354 | (output "") ; result to display |
| 355 | (wbuf ielm-working-buffer) ; current buffer after evaluation |
| 356 | (pmark (ielm-pm))) |
| 357 | (unless (ielm-is-whitespace-or-comment string) |
| 358 | (condition-case err |
| 359 | (let ((rout (read-from-string string))) |
| 360 | (setq form (car rout) |
| 361 | pos (cdr rout))) |
| 362 | (error (setq result (error-message-string err)) |
| 363 | (setq error-type "Read error"))) |
| 364 | (unless error-type |
| 365 | ;; Make sure working buffer has not been killed |
| 366 | (if (not (buffer-name ielm-working-buffer)) |
| 367 | (setq result "Working buffer has been killed" |
| 368 | error-type "IELM Error" |
| 369 | wbuf (current-buffer)) |
| 370 | (if (ielm-is-whitespace-or-comment (substring string pos)) |
| 371 | ;; To correctly handle the ielm-local variables *, |
| 372 | ;; ** and ***, we need a temporary buffer to be |
| 373 | ;; current at entry to the inner of the next two let |
| 374 | ;; forms. We need another temporary buffer to exit |
| 375 | ;; that same let. To avoid problems, neither of |
| 376 | ;; these buffers should be alive during the |
| 377 | ;; evaluation of form. |
| 378 | (let* ((*1 *) |
| 379 | (*2 **) |
| 380 | (*3 ***) |
| 381 | (active-process (ielm-process)) |
| 382 | (old-standard-output standard-output) |
| 383 | new-standard-output |
| 384 | ielm-temp-buffer) |
| 385 | (set-match-data ielm-match-data) |
| 386 | (save-excursion |
| 387 | (with-temp-buffer |
| 388 | (condition-case err |
| 389 | (unwind-protect |
| 390 | ;; The next let form creates default |
| 391 | ;; bindings for *, ** and ***. But |
| 392 | ;; these default bindings are |
| 393 | ;; identical to the ielm-local |
| 394 | ;; bindings. Hence, during the |
| 395 | ;; evaluation of form, the |
| 396 | ;; ielm-local values are going to be |
| 397 | ;; used in all buffers except for |
| 398 | ;; other ielm buffers, which override |
| 399 | ;; them. Normally, the variables *1, |
| 400 | ;; *2 and *3 also have default |
| 401 | ;; bindings, which are not overridden. |
| 402 | (let ((* *1) |
| 403 | (** *2) |
| 404 | (*** *3)) |
| 405 | (when (eq standard-output t) |
| 406 | (setf new-standard-output |
| 407 | (ielm-standard-output-impl |
| 408 | active-process)) |
| 409 | (setf standard-output new-standard-output)) |
| 410 | (kill-buffer (current-buffer)) |
| 411 | (set-buffer wbuf) |
| 412 | (setq result |
| 413 | (eval form lexical-binding)) |
| 414 | (setq wbuf (current-buffer)) |
| 415 | (setq |
| 416 | ielm-temp-buffer |
| 417 | (generate-new-buffer " *ielm-temp*")) |
| 418 | (set-buffer ielm-temp-buffer)) |
| 419 | (when ielm-temp-buffer |
| 420 | (kill-buffer ielm-temp-buffer)) |
| 421 | (when (eq new-standard-output standard-output) |
| 422 | (ignore-errors |
| 423 | (funcall standard-output t)) |
| 424 | (setf standard-output old-standard-output))) |
| 425 | (error (setq result (error-message-string err)) |
| 426 | (setq error-type "Eval error")) |
| 427 | (quit (setq result "Quit during evaluation") |
| 428 | (setq error-type "Eval error"))))) |
| 429 | (setq ielm-match-data (match-data))) |
| 430 | (setq error-type "IELM error") |
| 431 | (setq result "More than one sexp in input")))) |
| 432 | |
| 433 | ;; If the eval changed the current buffer, mention it here |
| 434 | (unless (eq wbuf ielm-working-buffer) |
| 435 | (message "current buffer is now: %s" wbuf) |
| 436 | (setq ielm-working-buffer wbuf)) |
| 437 | |
| 438 | (goto-char pmark) |
| 439 | (unless error-type |
| 440 | (condition-case nil |
| 441 | ;; Self-referential objects cause loops in the printer, so |
| 442 | ;; trap quits here. May as well do errors, too |
| 443 | (unless for-effect |
| 444 | (setq output (concat output (pp-to-string result) |
| 445 | (let ((str (eval-expression-print-format result))) |
| 446 | (if str (propertize str 'font-lock-face 'shadow)))))) |
| 447 | (error (setq error-type "IELM Error") |
| 448 | (setq result "Error during pretty-printing (bug in pp)")) |
| 449 | (quit (setq error-type "IELM Error") |
| 450 | (setq result "Quit during pretty-printing")))) |
| 451 | (if error-type |
| 452 | (progn |
| 453 | (when ielm-noisy (ding)) |
| 454 | (setq output (concat output "*** " error-type " *** ")) |
| 455 | (setq output (concat output result))) |
| 456 | ;; There was no error, so shift the *** values |
| 457 | (setq *** **) |
| 458 | (setq ** *) |
| 459 | (setq * result)) |
| 460 | (when (or (not for-effect) (not (equal output ""))) |
| 461 | (setq output (concat output "\n")))) |
| 462 | (setq output (concat output ielm-prompt-internal)) |
| 463 | (comint-output-filter (ielm-process) output))) |
| 464 | |
| 465 | ;;; Process and marker utilities |
| 466 | |
| 467 | (defun ielm-process nil |
| 468 | ;; Return the current buffer's process. |
| 469 | (get-buffer-process (current-buffer))) |
| 470 | |
| 471 | (defun ielm-pm nil |
| 472 | ;; Return the process mark of the current buffer. |
| 473 | (process-mark (get-buffer-process (current-buffer)))) |
| 474 | |
| 475 | (defun ielm-set-pm (pos) |
| 476 | ;; Set the process mark in the current buffer to POS. |
| 477 | (set-marker (process-mark (get-buffer-process (current-buffer))) pos)) |
| 478 | |
| 479 | ;;; Major mode |
| 480 | |
| 481 | (define-derived-mode inferior-emacs-lisp-mode comint-mode "IELM" |
| 482 | "Major mode for interactively evaluating Emacs Lisp expressions. |
| 483 | Uses the interface provided by `comint-mode' (which see). |
| 484 | |
| 485 | * \\<ielm-map>\\[ielm-send-input] evaluates the sexp following the prompt. There must be at most |
| 486 | one top level sexp per prompt. |
| 487 | |
| 488 | * \\[ielm-return] inserts a newline and indents, or evaluates a |
| 489 | complete expression (but see variable `ielm-dynamic-return'). |
| 490 | Inputs longer than one line are moved to the line following the |
| 491 | prompt (but see variable `ielm-dynamic-multiline-inputs'). |
| 492 | |
| 493 | * \\[ielm-return-for-effect] works like `ielm-return', except |
| 494 | that it doesn't print the result of evaluating the input. This |
| 495 | functionality is useful when forms would generate voluminous |
| 496 | output. |
| 497 | |
| 498 | * \\[completion-at-point] completes Lisp symbols (or filenames, within strings), |
| 499 | or indents the line if there is nothing to complete. |
| 500 | |
| 501 | The current working buffer may be changed (with a call to `set-buffer', |
| 502 | or with \\[ielm-change-working-buffer]), and its value is preserved between successive |
| 503 | evaluations. In this way, expressions may be evaluated in a different |
| 504 | buffer than the *ielm* buffer. By default, its name is shown on the |
| 505 | mode line; you can always display it with \\[ielm-print-working-buffer], or the buffer itself |
| 506 | with \\[ielm-display-working-buffer]. |
| 507 | |
| 508 | During evaluations, the values of the variables `*', `**', and `***' |
| 509 | are the results of the previous, second previous and third previous |
| 510 | evaluations respectively. If the working buffer is another IELM |
| 511 | buffer, then the values in the working buffer are used. The variables |
| 512 | `*1', `*2' and `*3', yield the process buffer values. |
| 513 | |
| 514 | If, at the start of evaluation, `standard-output' is `t' (the |
| 515 | default), `standard-output' is set to a special function that |
| 516 | causes output to be directed to the ielm buffer. |
| 517 | `standard-output' is restored after evaluation unless explicitly |
| 518 | set to a different value during evaluation. You can use (princ |
| 519 | VALUE) or (pp VALUE) to write to the ielm buffer. |
| 520 | |
| 521 | Expressions evaluated by IELM are not subject to `debug-on-quit' or |
| 522 | `debug-on-error'. |
| 523 | |
| 524 | The behavior of IELM may be customized with the following variables: |
| 525 | * To stop beeping on error, set `ielm-noisy' to nil. |
| 526 | * If you don't like the prompt, you can change it by setting `ielm-prompt'. |
| 527 | * If you do not like that the prompt is (by default) read-only, set |
| 528 | `ielm-prompt-read-only' to nil. |
| 529 | * Set `ielm-dynamic-return' to nil for bindings like `lisp-interaction-mode'. |
| 530 | * Entry to this mode runs `comint-mode-hook' and `ielm-mode-hook' |
| 531 | (in that order). |
| 532 | |
| 533 | Customized bindings may be defined in `ielm-map', which currently contains: |
| 534 | \\{ielm-map}" |
| 535 | :syntax-table emacs-lisp-mode-syntax-table |
| 536 | |
| 537 | (setq comint-prompt-regexp (concat "^" (regexp-quote ielm-prompt))) |
| 538 | (set (make-local-variable 'paragraph-separate) "\\'") |
| 539 | (set (make-local-variable 'paragraph-start) comint-prompt-regexp) |
| 540 | (setq comint-input-sender 'ielm-input-sender) |
| 541 | (setq comint-process-echoes nil) |
| 542 | (set (make-local-variable 'completion-at-point-functions) |
| 543 | '(comint-replace-by-expanded-history |
| 544 | ielm-complete-filename lisp-completion-at-point)) |
| 545 | (set (make-local-variable 'ielm-prompt-internal) ielm-prompt) |
| 546 | (set (make-local-variable 'comint-prompt-read-only) ielm-prompt-read-only) |
| 547 | (setq comint-get-old-input 'ielm-get-old-input) |
| 548 | (set (make-local-variable 'comint-completion-addsuffix) '("/" . "")) |
| 549 | (setq mode-line-process '(":%s on " (:eval (buffer-name ielm-working-buffer)))) |
| 550 | ;; Useful for `hs-minor-mode'. |
| 551 | (setq-local comment-start ";") |
| 552 | (setq-local comment-use-syntax t) |
| 553 | |
| 554 | (set (make-local-variable 'indent-line-function) 'ielm-indent-line) |
| 555 | (set (make-local-variable 'ielm-working-buffer) (current-buffer)) |
| 556 | (set (make-local-variable 'fill-paragraph-function) 'lisp-fill-paragraph) |
| 557 | |
| 558 | ;; Value holders |
| 559 | (set (make-local-variable '*) nil) |
| 560 | (set (make-local-variable '**) nil) |
| 561 | (set (make-local-variable '***) nil) |
| 562 | (set (make-local-variable 'ielm-match-data) nil) |
| 563 | |
| 564 | ;; font-lock support |
| 565 | (set (make-local-variable 'font-lock-defaults) |
| 566 | '(ielm-font-lock-keywords nil nil ((?: . "w") (?- . "w") (?* . "w")))) |
| 567 | |
| 568 | ;; A dummy process to keep comint happy. It will never get any input |
| 569 | (unless (comint-check-proc (current-buffer)) |
| 570 | ;; Was cat, but on non-Unix platforms that might not exist, so |
| 571 | ;; use hexl instead, which is part of the Emacs distribution. |
| 572 | (condition-case nil |
| 573 | (start-process "ielm" (current-buffer) "hexl") |
| 574 | (file-error (start-process "ielm" (current-buffer) "cat"))) |
| 575 | (set-process-query-on-exit-flag (ielm-process) nil) |
| 576 | (goto-char (point-max)) |
| 577 | |
| 578 | ;; Lisp output can include raw characters that confuse comint's |
| 579 | ;; carriage control code. |
| 580 | (set (make-local-variable 'comint-inhibit-carriage-motion) t) |
| 581 | |
| 582 | ;; Add a silly header |
| 583 | (insert ielm-header) |
| 584 | (ielm-set-pm (point-max)) |
| 585 | (unless comint-use-prompt-regexp |
| 586 | (let ((inhibit-read-only t)) |
| 587 | (add-text-properties |
| 588 | (point-min) (point-max) |
| 589 | '(rear-nonsticky t field output inhibit-line-move-field-capture t)))) |
| 590 | (comint-output-filter (ielm-process) ielm-prompt-internal) |
| 591 | (set-marker comint-last-input-start (ielm-pm)) |
| 592 | (set-process-filter (get-buffer-process (current-buffer)) 'comint-output-filter))) |
| 593 | |
| 594 | (defun ielm-get-old-input nil |
| 595 | ;; Return the previous input surrounding point |
| 596 | (save-excursion |
| 597 | (beginning-of-line) |
| 598 | (unless (looking-at-p comint-prompt-regexp) |
| 599 | (re-search-backward comint-prompt-regexp)) |
| 600 | (comint-skip-prompt) |
| 601 | (buffer-substring (point) (progn (forward-sexp 1) (point))))) |
| 602 | |
| 603 | ;;; User command |
| 604 | |
| 605 | ;;;###autoload |
| 606 | (defun ielm nil |
| 607 | "Interactively evaluate Emacs Lisp expressions. |
| 608 | Switches to the buffer `*ielm*', or creates it if it does not exist. |
| 609 | See `inferior-emacs-lisp-mode' for details." |
| 610 | (interactive) |
| 611 | (let (old-point) |
| 612 | (unless (comint-check-proc "*ielm*") |
| 613 | (with-current-buffer (get-buffer-create "*ielm*") |
| 614 | (unless (zerop (buffer-size)) (setq old-point (point))) |
| 615 | (inferior-emacs-lisp-mode))) |
| 616 | (switch-to-buffer "*ielm*") |
| 617 | (when old-point (push-mark old-point)))) |
| 618 | |
| 619 | (provide 'ielm) |
| 620 | |
| 621 | ;;; ielm.el ends here |