lisp/progmodes/scheme.el

   1 ;; Scheme mode, and its idiosyncratic commands.
   2 ;; Copyright (C) 1986, 1987, 1988 Free Software Foundation, Inc.
   3 ;; Adapted from Lisp mode by Bill Rozas, jinx@prep.
   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 1, 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
  22 ;; Initially a query replace of Lisp mode, except for the indentation
  23 ;; of special forms.  Probably the code should be merged at some point
  24 ;; so that there is sharing between both libraries.
  25
  26 ;;; $Header: scheme.el,v 1.7 88/07/15 20:20:00 GMT cph Exp $
  27
  28 \f
  29 (defvar scheme-mode-syntax-table nil "")
  30 (if (not scheme-mode-syntax-table)
  31     (let ((i 0))
  32       (setq scheme-mode-syntax-table (make-syntax-table))
  33       (set-syntax-table scheme-mode-syntax-table)
  34
  35       ;; Default is atom-constituent.
  36       (while (< i 256)
  37         (modify-syntax-entry i "_   ")
  38         (setq i (1+ i)))
  39
  40       ;; Word components.
  41       (setq i ?0)
  42       (while (<= i ?9)
  43         (modify-syntax-entry i "w   ")
  44         (setq i (1+ i)))
  45       (setq i ?A)
  46       (while (<= i ?Z)
  47         (modify-syntax-entry i "w   ")
  48         (setq i (1+ i)))
  49       (setq i ?a)
  50       (while (<= i ?z)
  51         (modify-syntax-entry i "w   ")
  52         (setq i (1+ i)))
  53
  54       ;; Whitespace
  55       (modify-syntax-entry ?\t "    ")
  56       (modify-syntax-entry ?\n ">   ")
  57       (modify-syntax-entry ?\f "    ")
  58       (modify-syntax-entry ?\r "    ")
  59       (modify-syntax-entry ?  "    ")
  60
  61       ;; These characters are delimiters but otherwise undefined.
  62       ;; Brackets and braces balance for editing convenience.
  63       (modify-syntax-entry ?[ "(]  ")
  64       (modify-syntax-entry ?] ")[  ")
  65       (modify-syntax-entry ?{ "(}  ")
  66       (modify-syntax-entry ?} "){  ")
  67       (modify-syntax-entry ?\| "  23")
  68
  69       ;; Other atom delimiters
  70       (modify-syntax-entry ?\( "()  ")
  71       (modify-syntax-entry ?\) ")(  ")
  72       (modify-syntax-entry ?\; "<   ")
  73       (modify-syntax-entry ?\" "\"    ")
  74       (modify-syntax-entry ?' "  p")
  75       (modify-syntax-entry ?` "  p")
  76
  77       ;; Special characters
  78       (modify-syntax-entry ?, "_ p")
  79       (modify-syntax-entry ?@ "_ p")
  80       (modify-syntax-entry ?# "_ p14")
  81       (modify-syntax-entry ?\\ "\\   ")))
  82 \f
  83 (defvar scheme-mode-abbrev-table nil "")
  84 (define-abbrev-table 'scheme-mode-abbrev-table ())
  85
  86 (defun scheme-mode-variables ()
  87   (set-syntax-table scheme-mode-syntax-table)
  88   (setq local-abbrev-table scheme-mode-abbrev-table)
  89   (make-local-variable 'paragraph-start)
  90   (setq paragraph-start (concat "^$\\|" page-delimiter))
  91   (make-local-variable 'paragraph-separate)
  92   (setq paragraph-separate paragraph-start)
  93   (make-local-variable 'paragraph-ignore-fill-prefix)
  94   (setq paragraph-ignore-fill-prefix t)
  95   (make-local-variable 'indent-line-function)
  96   (setq indent-line-function 'scheme-indent-line)
  97   (make-local-variable 'comment-start)
  98   (setq comment-start ";")
  99   (make-local-variable 'comment-start-skip)
 100   (setq comment-start-skip ";+[ \t]*")
 101   (make-local-variable 'comment-column)
 102   (setq comment-column 40)
 103   (make-local-variable 'comment-indent-hook)
 104   (setq comment-indent-hook 'scheme-comment-indent)
 105   (setq mode-line-process '("" scheme-mode-line-process)))
 106
 107 (defvar scheme-mode-line-process "")
 108
 109 (defun scheme-mode-commands (map)
 110   (define-key map "\t" 'scheme-indent-line)
 111   (define-key map "\177" 'backward-delete-char-untabify)
 112   (define-key map "\e\C-q" 'scheme-indent-sexp))
 113
 114 (defvar scheme-mode-map nil)
 115 (if (not scheme-mode-map)
 116     (progn
 117       (setq scheme-mode-map (make-sparse-keymap))
 118       (scheme-mode-commands scheme-mode-map)))
 119 \f
 120 ;;;###autoload
 121 (defun scheme-mode ()
 122   "Major mode for editing Scheme code.
 123 Editing commands are similar to those of lisp-mode.
 124
 125 In addition, if an inferior Scheme process is running, some additional
 126 commands will be defined, for evaluating expressions and controlling
 127 the interpreter, and the state of the process will be displayed in the
 128 modeline of all Scheme buffers.  The names of commands that interact
 129 with the Scheme process start with \"xscheme-\".  For more information
 130 see the documentation for xscheme-interaction-mode.
 131
 132 Commands:
 133 Delete converts tabs to spaces as it moves back.
 134 Blank lines separate paragraphs.  Semicolons start comments.
 135 \\{scheme-mode-map}
 136 Entry to this mode calls the value of scheme-mode-hook
 137 if that value is non-nil."
 138   (interactive)
 139   (kill-all-local-variables)
 140   (scheme-mode-initialize)
 141   (scheme-mode-variables)
 142   (run-hooks 'scheme-mode-hook))
 143
 144 (defun scheme-mode-initialize ()
 145   (use-local-map scheme-mode-map)
 146   (setq major-mode 'scheme-mode)
 147   (setq mode-name "Scheme"))
 148
 149 (defvar scheme-mit-dialect t
 150   "If non-nil, scheme mode is specialized for MIT Scheme.
 151 Set this to nil if you normally use another dialect.")
 152 \f
 153 (defun scheme-comment-indent (&optional pos)
 154   (save-excursion
 155     (if pos (goto-char pos))
 156     (cond ((looking-at ";;;") (current-column))
 157           ((looking-at ";;")
 158            (let ((tem (calculate-scheme-indent)))
 159              (if (listp tem) (car tem) tem)))
 160           (t
 161            (skip-chars-backward " \t")
 162            (max (if (bolp) 0 (1+ (current-column)))
 163                 comment-column)))))
 164
 165 (defvar scheme-indent-offset nil "")
 166 (defvar scheme-indent-function 'scheme-indent-function "")
 167
 168 (defun scheme-indent-line (&optional whole-exp)
 169   "Indent current line as Scheme code.
 170 With argument, indent any additional lines of the same expression
 171 rigidly along with this one."
 172   (interactive "P")
 173   (let ((indent (calculate-scheme-indent)) shift-amt beg end
 174         (pos (- (point-max) (point))))
 175     (beginning-of-line)
 176     (setq beg (point))
 177     (skip-chars-forward " \t")
 178     (if (looking-at "[ \t]*;;;")
 179         ;; Don't alter indentation of a ;;; comment line.
 180         nil
 181       (if (listp indent) (setq indent (car indent)))
 182       (setq shift-amt (- indent (current-column)))
 183       (if (zerop shift-amt)
 184           nil
 185         (delete-region beg (point))
 186         (indent-to indent))
 187       ;; If initial point was within line's indentation,
 188       ;; position after the indentation.  Else stay at same point in text.
 189       (if (> (- (point-max) pos) (point))
 190           (goto-char (- (point-max) pos)))
 191       ;; If desired, shift remaining lines of expression the same amount.
 192       (and whole-exp (not (zerop shift-amt))
 193            (save-excursion
 194              (goto-char beg)
 195              (forward-sexp 1)
 196              (setq end (point))
 197              (goto-char beg)
 198              (forward-line 1)
 199              (setq beg (point))
 200              (> end beg))
 201            (indent-code-rigidly beg end shift-amt)))))
 202 \f
 203 (defun calculate-scheme-indent (&optional parse-start)
 204   "Return appropriate indentation for current line as scheme code.
 205 In usual case returns an integer: the column to indent to.
 206 Can instead return a list, whose car is the column to indent to.
 207 This means that following lines at the same level of indentation
 208 should not necessarily be indented the same way.
 209 The second element of the list is the buffer position
 210 of the start of the containing expression."
 211   (save-excursion
 212     (beginning-of-line)
 213     (let ((indent-point (point)) state paren-depth desired-indent (retry t)
 214           last-sexp containing-sexp first-sexp-list-p)
 215       (if parse-start
 216           (goto-char parse-start)
 217         (beginning-of-defun))
 218       ;; Find outermost containing sexp
 219       (while (< (point) indent-point)
 220         (setq state (parse-partial-sexp (point) indent-point 0)))
 221       ;; Find innermost containing sexp
 222       (while (and retry (setq paren-depth (car state)) (> paren-depth 0))
 223         (setq retry nil)
 224         (setq last-sexp (nth 2 state))
 225         (setq containing-sexp (car (cdr state)))
 226         ;; Position following last unclosed open.
 227         (goto-char (1+ containing-sexp))
 228         ;; Is there a complete sexp since then?
 229         (if (and last-sexp (> last-sexp (point)))
 230             ;; Yes, but is there a containing sexp after that?
 231             (let ((peek (parse-partial-sexp last-sexp indent-point 0)))
 232               (if (setq retry (car (cdr peek))) (setq state peek))))
 233         (if (not retry)
 234             ;; Innermost containing sexp found
 235             (progn
 236               (goto-char (1+ containing-sexp))
 237               (if (not last-sexp)
 238                   ;; indent-point immediately follows open paren.
 239                   ;; Don't call hook.
 240                   (setq desired-indent (current-column))
 241                 ;; Move to first sexp after containing open paren
 242                 (parse-partial-sexp (point) last-sexp 0 t)
 243                 (setq first-sexp-list-p (looking-at "\\s("))
 244                 (cond
 245                  ((> (save-excursion (forward-line 1) (point))
 246                      last-sexp)
 247                   ;; Last sexp is on same line as containing sexp.
 248                   ;; It's almost certainly a function call.
 249                   (parse-partial-sexp (point) last-sexp 0 t)
 250                   (if (/= (point) last-sexp)
 251                       ;; Indent beneath first argument or, if only one sexp
 252                       ;; on line, indent beneath that.
 253                       (progn (forward-sexp 1)
 254                              (parse-partial-sexp (point) last-sexp 0 t)))
 255                   (backward-prefix-chars))
 256                  (t
 257                   ;; Indent beneath first sexp on same line as last-sexp.
 258                   ;; Again, it's almost certainly a function call.
 259                   (goto-char last-sexp)
 260                   (beginning-of-line)
 261                   (parse-partial-sexp (point) last-sexp 0 t)
 262                   (backward-prefix-chars)))))))
 263       ;; If looking at a list, don't call hook.
 264       (if first-sexp-list-p
 265           (setq desired-indent (current-column)))
 266       ;; Point is at the point to indent under unless we are inside a string.
 267       ;; Call indentation hook except when overriden by scheme-indent-offset
 268       ;; or if the desired indentation has already been computed.
 269       (cond ((car (nthcdr 3 state))
 270              ;; Inside a string, don't change indentation.
 271              (goto-char indent-point)
 272              (skip-chars-forward " \t")
 273              (setq desired-indent (current-column)))
 274             ((and (integerp scheme-indent-offset) containing-sexp)
 275              ;; Indent by constant offset
 276              (goto-char containing-sexp)
 277              (setq desired-indent (+ scheme-indent-offset (current-column))))
 278             ((not (or desired-indent
 279                       (and (boundp 'scheme-indent-function)
 280                            scheme-indent-function
 281                            (not retry)
 282                            (setq desired-indent
 283                                  (funcall scheme-indent-function
 284                                           indent-point state)))))
 285              ;; Use default indentation if not computed yet
 286              (setq desired-indent (current-column))))
 287       desired-indent)))
 288 \f
 289 (defun scheme-indent-function (indent-point state)
 290   (let ((normal-indent (current-column)))
 291     (save-excursion
 292       (goto-char (1+ (car (cdr state))))
 293       (re-search-forward "\\sw\\|\\s_")
 294       (if (/= (point) (car (cdr state)))
 295           (let ((function (buffer-substring (progn (forward-char -1) (point))
 296                                             (progn (forward-sexp 1) (point))))
 297                 method)
 298             ;; Who cares about this, really?
 299             ;(if (not (string-match "\\\\\\||" function)))
 300             (setq function (downcase function))
 301             (setq method (get (intern-soft function) 'scheme-indent-function))
 302             (cond ((integerp method)
 303                    (scheme-indent-specform method state indent-point))
 304                   (method
 305                    (funcall method state indent-point))
 306                   ((and (> (length function) 3)
 307                         (string-equal (substring function 0 3) "def"))
 308                    (scheme-indent-defform state indent-point))))))))
 309
 310 (defvar scheme-body-indent 2 "")
 311 \f
 312 (defun scheme-indent-specform (count state indent-point)
 313   (let ((containing-form-start (car (cdr state))) (i count)
 314         body-indent containing-form-column)
 315     ;; Move to the start of containing form, calculate indentation
 316     ;; to use for non-distinguished forms (> count), and move past the
 317     ;; function symbol.  scheme-indent-function guarantees that there is at
 318     ;; least one word or symbol character following open paren of containing
 319     ;; form.
 320     (goto-char containing-form-start)
 321     (setq containing-form-column (current-column))
 322     (setq body-indent (+ scheme-body-indent containing-form-column))
 323     (forward-char 1)
 324     (forward-sexp 1)
 325     ;; Now find the start of the last form.
 326     (parse-partial-sexp (point) indent-point 1 t)
 327     (while (and (< (point) indent-point)
 328                 (condition-case nil
 329                     (progn
 330                       (setq count (1- count))
 331                       (forward-sexp 1)
 332                       (parse-partial-sexp (point) indent-point 1 t))
 333                   (error nil))))
 334     ;; Point is sitting on first character of last (or count) sexp.
 335     (cond ((> count 0)
 336            ;; A distinguished form.  Use double scheme-body-indent.
 337            (list (+ containing-form-column (* 2 scheme-body-indent))
 338                  containing-form-start))
 339           ;; A non-distinguished form. Use body-indent if there are no
 340           ;; distinguished forms and this is the first undistinguished
 341           ;; form, or if this is the first undistinguished form and
 342           ;; the preceding distinguished form has indentation at least
 343           ;; as great as body-indent.
 344           ((and (= count 0)
 345                 (or (= i 0)
 346                     (<= body-indent normal-indent)))
 347            body-indent)
 348           (t
 349            normal-indent))))
 350
 351 (defun scheme-indent-defform (state indent-point)
 352   (goto-char (car (cdr state)))
 353   (forward-line 1)
 354   (if (> (point) (car (cdr (cdr state))))
 355       (progn
 356         (goto-char (car (cdr state)))
 357         (+ scheme-body-indent (current-column)))))
 358 \f
 359 ;;; Let is different in Scheme
 360
 361 (defun would-be-symbol (string)
 362   (not (string-equal (substring string 0 1) "(")))
 363
 364 (defun next-sexp-as-string ()
 365   ;; Assumes that protected by a save-excursion
 366   (forward-sexp 1)
 367   (let ((the-end (point)))
 368     (backward-sexp 1)
 369     (buffer-substring (point) the-end)))
 370
 371 ;; This is correct but too slow.
 372 ;; The one below works almost always.
 373 ;;(defun scheme-let-indent (state indent-point)
 374 ;;  (if (would-be-symbol (next-sexp-as-string))
 375 ;;      (scheme-indent-specform 2 state indent-point)
 376 ;;      (scheme-indent-specform 1 state indent-point)))
 377
 378 (defun scheme-let-indent (state indent-point)
 379   (skip-chars-forward " \t")
 380   (if (looking-at "[a-zA-Z0-9+-*/?!@$%^&_:~]")
 381       (scheme-indent-specform 2 state indent-point)
 382       (scheme-indent-specform 1 state indent-point)))
 383
 384 ;; (put 'begin 'scheme-indent-function 0), say, causes begin to be indented
 385 ;; like defun if the first form is placed on the next line, otherwise
 386 ;; it is indented like any other form (i.e. forms line up under first).
 387
 388 (put 'begin 'scheme-indent-function 0)
 389 (put 'case 'scheme-indent-function 1)
 390 (put 'delay 'scheme-indent-function 0)
 391 (put 'do 'scheme-indent-function 2)
 392 (put 'lambda 'scheme-indent-function 1)
 393 (put 'let 'scheme-indent-function 'scheme-let-indent)
 394 (put 'let* 'scheme-indent-function 1)
 395 (put 'letrec 'scheme-indent-function 1)
 396 (put 'sequence 'scheme-indent-function 0)
 397
 398 (put 'call-with-input-file 'scheme-indent-function 1)
 399 (put 'with-input-from-file 'scheme-indent-function 1)
 400 (put 'with-input-from-port 'scheme-indent-function 1)
 401 (put 'call-with-output-file 'scheme-indent-function 1)
 402 (put 'with-output-to-file 'scheme-indent-function 1)
 403 (put 'with-output-to-port 'scheme-indent-function 1)
 404 \f
 405 ;;;; MIT Scheme specific indentation.
 406
 407 (if scheme-mit-dialect
 408     (progn
 409       (put 'fluid-let 'scheme-indent-function 1)
 410       (put 'in-package 'scheme-indent-function 1)
 411       (put 'let-syntax 'scheme-indent-function 1)
 412       (put 'local-declare 'scheme-indent-function 1)
 413       (put 'macro 'scheme-indent-function 1)
 414       (put 'make-environment 'scheme-indent-function 0)
 415       (put 'named-lambda 'scheme-indent-function 1)
 416       (put 'using-syntax 'scheme-indent-function 1)
 417
 418       (put 'with-input-from-string 'scheme-indent-function 1)
 419       (put 'with-output-to-string 'scheme-indent-function 0)
 420       (put 'with-values 'scheme-indent-function 1)
 421
 422       (put 'syntax-table-define 'scheme-indent-function 2)
 423       (put 'list-transform-positive 'scheme-indent-function 1)
 424       (put 'list-transform-negative 'scheme-indent-function 1)
 425       (put 'list-search-positive 'scheme-indent-function 1)
 426       (put 'list-search-negative 'scheme-indent-function 1)
 427
 428       (put 'access-components 'scheme-indent-function 1)
 429       (put 'assignment-components 'scheme-indent-function 1)
 430       (put 'combination-components 'scheme-indent-function 1)
 431       (put 'comment-components 'scheme-indent-function 1)
 432       (put 'conditional-components 'scheme-indent-function 1)
 433       (put 'disjunction-components 'scheme-indent-function 1)
 434       (put 'declaration-components 'scheme-indent-function 1)
 435       (put 'definition-components 'scheme-indent-function 1)
 436       (put 'delay-components 'scheme-indent-function 1)
 437       (put 'in-package-components 'scheme-indent-function 1)
 438       (put 'lambda-components 'scheme-indent-function 1)
 439       (put 'lambda-components* 'scheme-indent-function 1)
 440       (put 'lambda-components** 'scheme-indent-function 1)
 441       (put 'open-block-components 'scheme-indent-function 1)
 442       (put 'pathname-components 'scheme-indent-function 1)
 443       (put 'procedure-components 'scheme-indent-function 1)
 444       (put 'sequence-components 'scheme-indent-function 1)
 445       (put 'unassigned\?-components 'scheme-indent-function 1)
 446       (put 'unbound\?-components 'scheme-indent-function 1)
 447       (put 'variable-components 'scheme-indent-function 1)))
 448 \f
 449 (defun scheme-indent-sexp ()
 450   "Indent each line of the list starting just after point."
 451   (interactive)
 452   (let ((indent-stack (list nil)) (next-depth 0) bol
 453         outer-loop-done inner-loop-done state this-indent)
 454     (save-excursion (forward-sexp 1))
 455     (save-excursion
 456       (setq outer-loop-done nil)
 457       (while (not outer-loop-done)
 458         (setq last-depth next-depth
 459               innerloop-done nil)
 460         (while (and (not innerloop-done)
 461                     (not (setq outer-loop-done (eobp))))
 462           (setq state (parse-partial-sexp (point) (progn (end-of-line) (point))
 463                                           nil nil state))
 464           (setq next-depth (car state))
 465           (if (car (nthcdr 4 state))
 466               (progn (indent-for-comment)
 467                      (end-of-line)
 468                      (setcar (nthcdr 4 state) nil)))
 469           (if (car (nthcdr 3 state))
 470               (progn
 471                 (forward-line 1)
 472                 (setcar (nthcdr 5 state) nil))
 473             (setq innerloop-done t)))
 474         (if (setq outer-loop-done (<= next-depth 0))
 475             nil
 476           (while (> last-depth next-depth)
 477             (setq indent-stack (cdr indent-stack)
 478                   last-depth (1- last-depth)))
 479           (while (< last-depth next-depth)
 480             (setq indent-stack (cons nil indent-stack)
 481                   last-depth (1+ last-depth)))
 482           (forward-line 1)
 483           (setq bol (point))
 484           (skip-chars-forward " \t")
 485           (if (or (eobp) (looking-at "[;\n]"))
 486               nil
 487             (if (and (car indent-stack)
 488                      (>= (car indent-stack) 0))
 489                 (setq this-indent (car indent-stack))
 490               (let ((val (calculate-scheme-indent
 491                           (if (car indent-stack) (- (car indent-stack))))))
 492                 (if (integerp val)
 493                     (setcar indent-stack
 494                             (setq this-indent val))
 495                   (setcar indent-stack (- (car (cdr val))))
 496                   (setq this-indent (car val)))))
 497             (if (/= (current-column) this-indent)
 498                 (progn (delete-region bol (point))
 499                        (indent-to this-indent)))))))))
 500
 501 (provide 'scheme)