--- /dev/null
+;;; lmc.el --- Little Man Computer in Elisp
+
+;; Copyright (C) 2011 Free Software Foundation, Inc.
+
+;; Author: Stefan Monnier <monnier@iro.umontreal.ca>
+
+;; This program is free software; you can redistribute it and/or modify
+;; it under the terms of the GNU General Public License as published by
+;; the Free Software Foundation, either version 3 of the License, or
+;; (at your option) any later version.
+
+;; This program is distributed in the hope that it will be useful,
+;; but WITHOUT ANY WARRANTY; without even the implied warranty of
+;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+;; GNU General Public License for more details.
+
+;; You should have received a copy of the GNU General Public License
+;; along with this program. If not, see <http://www.gnu.org/licenses/>.
+
+;;; Commentary:
+
+;; A simulator for the Little Man Computer.
+;; http://en.wikipedia.org/wiki/Little_man_computer
+
+;; The simulator uses a plain editable buffer, so you can edit the machine
+;; words just like any other text, and every word can be given a name (label)
+;; which can also be edited in the normal way.
+
+;; The assembly uses a slightly different (Lispish) syntax where each
+;; instruction needs to be wrapped in parentheses. Other than hat it's the
+;; same assembly as documented elsewhere (accepts a few mnemonic variants, such
+;; as IN/INP, STA/STO).
+;; The lmc-asm-mode supports all the usual editing features such as label
+;; completion, mnemonic completion, jumping to a label, automatic indentation,
+;; and even code folding.
+
+;; FIXME:
+;; - can't set lmc-pc and lmc-acc.
+
+;;; Code:
+
+(eval-when-compile (require 'cl))
+(require 'hexl)
+
+;;; The LMC-Simulator
+
+(defvar lmc--pc 0 "Program counter for LMC.")
+(make-variable-buffer-local 'lmc--pc)
+
+(defvar lmc-acc 0 "Accumulator for LMC.")
+(make-variable-buffer-local 'lmc--acc)
+
+;; (defun lmc-check (cmds)
+;; (dolist (cmd cmds)
+;; (pcase cmd
+;; ((pred symbolp)) ;A label.
+;; (`(,(or `IN `OUT `HLT `COB))) ;Arity-0 opcode.
+;; (`(,(or `LDA `STO `ADD `SUB `BR `BRZ `BRP `DAT) ;Arity-1 opcode.
+;; ,(or (pred lmc--numberp) (pred symbolp))))
+;; (_ (error "Unknown instruction %S" cmd)))))
+
+(defun lmc--numberp (n max)
+ (when (numberp n)
+ (or (and (or (natnump n) (error "%S is not a positive integer" n))
+ (or (< n max) (error "%S is too large" n))))))
+
+(defun lmc--resolve (arg labels max)
+ (if (lmc--numberp arg max) arg
+ (or (cdr (assq arg labels))
+ (error (if (symbolp arg)
+ "Unknown label %S"
+ "Arg %S is neither a label nor a number")
+ arg))))
+
+(defconst lmc-mnemonic-1-table '((LDA . 5)
+ (STO . 3) (STA . 3)
+ (ADD . 1)
+ (SUB . 2)
+ (BR . 6) (BRA . 6)
+ (BRZ . 7)
+ (BRP . 8))
+ "Mnemonic table for arity-1 instructions.")
+
+(defconst lmc-mnemonic-0-table '((HLT . 000) (COB . 000)
+ (IN . 901) (INP . 901)
+ (OUT . 902))
+ "Mnemonic table for arity-0 instructions.")
+
+(defun lmc--assemble (cmds)
+ ;; FIXME: Move to error position upon error.
+ (let ((pos 0)
+ (labels ()))
+ ;; First pass, resolve labels to their positions.
+ (dolist (cmd cmds)
+ (setq cmd (cdr cmd)) ;Ignore position info at this stage.
+ (if (or (consp cmd)
+ (assq cmd lmc-mnemonic-0-table))
+ (setq pos (+ pos (if (eq (car cmd) 'DAT)
+ (1- (length cmd)) 1)))
+ ;; (assert (symbolp cmd))
+ (push (cons cmd pos) labels)))
+ ;; Second pass, do the actual assembly.
+ (let* ((words ())
+ (ll nil)
+ (newword
+ (lambda (w &optional code)
+ (push (list w ll code) words) (setq ll nil))))
+ (dolist (cmd cmds)
+ (goto-char (pop cmd)) ;Move to start of CMD, in case of error.
+ (cond
+ ((assq cmd lmc-mnemonic-0-table)
+ (funcall newword (cdr (assq cmd lmc-mnemonic-0-table)) 'code))
+ ((and (null (cdr-safe cmd))
+ (assq (car-safe cmd) lmc-mnemonic-0-table))
+ (funcall newword (cdr (assq (car cmd) lmc-mnemonic-0-table)) 'code))
+ ((eq (car-safe cmd) 'DAT)
+ (dolist (arg (cdr cmd))
+ (funcall newword (lmc--resolve arg labels 1000))))
+ ((assq (car-safe cmd) lmc-mnemonic-1-table)
+ (funcall newword
+ (+ (* 100 (cdr (assq (car cmd) lmc-mnemonic-1-table)))
+ (lmc--resolve (nth 1 cmd) labels 100))
+ 'code))
+ ((and cmd (symbolp cmd))
+ (assert (eq (cdr (assq cmd labels)) (length words)))
+ (setq ll cmd))
+ (t (error "Invalid instruction %S" cmd))))
+ (nreverse words))))
+
+;; (defvar lmc-label-width 8)
+
+(defun lmc--load-word (word addr)
+ (assert (bolp))
+ (insert (propertize (format " %02d:\t" addr)
+ 'read-only t
+ 'front-sticky t
+ 'rear-nonsticky t))
+ (let ((word (car word))
+ (label (nth 1 word))
+ (code (nth 2 word)))
+ (let ((basepos (point))
+ (base (current-column)))
+ (if (and label (symbolp label))
+ (insert (symbol-name label)))
+ ;; (when (>= (current-column) (+ base tab-width))
+ ;; (while (>= (current-column) (+ base tab-width -1))
+ ;; (delete-char -1))
+ ;; (insert "…")
+ ;; (put-text-property basepos (point)
+ ;; 'help-echo (symbol-name label)))
+ ;; (insert (propertize
+ ;; (make-string (1+ (- lmc-label-width (current-column))) ?\s)
+ ;; 'display '(space :align-to (1+ lmc-label-width))))
+ (insert (eval-when-compile (propertize "\t"
+ 'read-only t
+ 'rear-nonsticky t))))
+ (insert (format " %03d" word))
+ (insert (if code
+ (eval-when-compile (propertize "\n"
+ 'lmc-code t
+ 'read-only t
+ 'rear-nonsticky t))
+ (eval-when-compile (propertize "\n"
+ 'read-only t
+ 'rear-nonsticky t))))))
+
+(defun lmc-disassemble-word (word)
+ (let ((code (car (rassq (/ word 100) lmc-mnemonic-1-table))))
+ (cond
+ (code (list code (mod word 100)))
+ ((rassq word lmc-mnemonic-1-table)
+ (list (car (rassq word lmc-mnemonic-1-table)))))))
+
+(defun lmc-addr->point (addr)
+ (goto-char (point-min))
+ (forward-line addr))
+
+(defun lmc-point->addr ()
+ (- (count-lines (point-min) (point)) (if (bolp) 0 1)))
+
+(defun lmc-get-word (&optional addr fix)
+ (save-excursion
+ (if (null addr)
+ (forward-line 0)
+ (lmc-addr->point addr))
+ (cond
+ ((re-search-forward "\t.*\t \\([0-9][0-9][0-9]\\)$"
+ (line-end-position) t)
+ (string-to-number (match-string 1)))
+ ((re-search-forward "\t.*\t\\(.*\\)$" (line-end-position) t)
+ (let ((n (string-to-number (match-string 1))))
+ (unless (integerp n) (setq n (truncate n)))
+ (setq n (mod n 1000))
+ (when fix
+ (replace-match (format " %03d" n) t t nil 1))
+ n))
+ (t 0))))
+
+(defconst lmc-label-re "^\\([^\t\n]*\\)\t\\(.*\\)\t *[0-9]")
+
+(defvar lmc-label-table nil)
+
+(defun lmc-record-label (addr label)
+ (let ((old (aref lmc-label-table addr)))
+ (unless (and old (equal (car old) label))
+ ;; (message "recordlabel %S = %S" addr label)
+ (aset lmc-label-table addr (list label))
+ (when (cdr old)
+ (run-with-timer
+ 0 nil
+ (lambda (buf refaddrs)
+ (with-current-buffer buf
+ (save-excursion
+ ;; (message "refreshlabel in %S" refaddrs)
+ (dolist (refaddr refaddrs)
+ (lmc-addr->point (1+ refaddr))
+ (unless (bobp)
+ (let ((inhibit-read-only t))
+ (put-text-property (1- (point)) (point)
+ 'fontified nil)))))))
+ (current-buffer) (cdr old))))))
+
+(defun lmc-get-label (addr)
+ (save-excursion
+ ;; (if (null addr)
+ ;; (forward-line 0)
+ (lmc-addr->point addr) ;; )
+ (let ((label (when (re-search-forward lmc-label-re nil t)
+ (if (> (match-end 2) (match-beginning 2))
+ (match-string 2)))))
+ (lmc-record-label addr label)
+ label)))
+
+
+(defun lmc-font-lock-opcode ()
+ (save-match-data
+ (when (get-text-property (line-end-position) 'lmc-code)
+ (let* ((word (lmc-get-word))
+ (code (lmc-disassemble-word word)))
+ ;; Resolve labels.
+ (when (integerp (nth 1 code))
+ (let* ((addr (nth 1 code))
+ (label (lmc-get-label addr)))
+ (pushnew (lmc-point->addr)
+ (cdr (aref lmc-label-table addr)))
+ (when label
+ (setf (nth 1 code) label))))
+ (put-text-property
+ (line-end-position) (1+ (line-end-position))
+ 'display
+ (format (eval-when-compile
+ (concat (propertize "\t" 'cursor t)
+ (propertize "%s" 'face font-lock-comment-face)
+ "\n"))
+ (or code '(Invalid opcode)))))
+ nil)))
+
+(defun lmc-font-lock-label ()
+ (lmc-record-label (lmc-point->addr)
+ (if (> (match-end 2) (match-beginning 2))
+ (match-string 2)))
+ (save-excursion
+ ;; ;; Replace any TAB found in label.
+ ;; (goto-char (match-beginning 2))
+ ;; (while (progn (skip-chars-forward "^\t" (match-end 2))
+ ;; (< (point) (match-end 2)))
+ ;; (insert " ") (delete-char 1))
+ ;; Truncate label's display if needed.
+ (move-to-column (1- (* 2 tab-width)))
+ (when (> (match-end 2) (point))
+ (forward-char -1)
+ (put-text-property (match-beginning 2) (match-end 2)
+ 'help-echo (match-string 2))
+ (put-text-property (point) (match-end 2) 'display "…")))
+ font-lock-constant-face)
+
+(defconst lmc-font-lock-keywords
+ `((,lmc-label-re
+ (1 'hexl-address-region)
+ (2 (lmc-font-lock-label)))
+ (".$" (0 (lmc-font-lock-opcode)))))
+
+(defun lmc-after-change (beg end len)
+ (unless inhibit-read-only
+ (save-excursion
+ ;; Replace any TAB or NL inserted, which could interfere with parsing.
+ (goto-char beg)
+ (while (progn (skip-chars-forward "^\t\n" end)
+ (< (point) end))
+ (insert " ") (delete-char 1)))))
+
+(defvar lmc-pc 0 "LMC program counter.")
+(make-variable-buffer-local 'lmc-pc)
+(defvar lmc-acc nil "LMC accumulator.")
+(make-variable-buffer-local 'lmc-acc)
+(defvar lmc-output nil "Past LMC output,")
+(make-variable-buffer-local 'lmc-output)
+
+(defvar lmc--stopped nil "State where we stopped.")
+(make-variable-buffer-local 'lmc--stopped)
+
+(defun lmc-update-pc ()
+ (setq lmc-pc (mod lmc-pc 100))
+ (lmc-addr->point lmc-pc)
+ (move-marker overlay-arrow-position (point))
+ (re-search-forward "\t.*\t *" nil t)
+ (unless (get-text-property (line-end-position) 'lmc-code)
+ (let ((inhibit-read-only t))
+ (put-text-property (line-end-position)
+ (min (1+ (line-end-position)) (point-max))
+ 'lmc-code t))))
+
+(defun lmc--state ()
+ (list (buffer-chars-modified-tick) lmc-acc lmc-pc))
+(defun lmc-stopped-p ()
+ (equal (lmc--state) lmc--stopped))
+
+;; FIXME: Add tool-bar to LMC-Sim.
+
+(defvar lmc-mode-map
+ (let ((map (make-sparse-keymap)))
+ (define-key map "\C-c\C-s" 'lmc-step)
+ (define-key map "\C-c\C-l" 'lmc-load-file)
+ map))
+
+(easy-menu-define lmc-menu lmc-mode-map "Menu for LMC-Sim."
+ '("LMC-Sim"
+ ["Step" lmc-step (not (lmc-stopped-p))]
+ ["Load file" lmc-load-file]))
+
+(define-derived-mode lmc-mode fundamental-mode "LMC-Sim"
+ "The simulator of the Little Man Computer."
+ (set (make-local-variable 'truncate-lines) t)
+ (set (make-local-variable 'truncate-partial-width-windows) t)
+ (set (make-local-variable 'tab-width) 10)
+ (set (make-local-variable 'font-lock-defaults)
+ '(lmc-font-lock-keywords t))
+ (set (make-local-variable 'font-lock-extra-managed-props)
+ '(display help-echo))
+ (add-hook 'after-change-functions #'lmc-after-change nil t)
+ (set (make-local-variable 'lmc-label-table) (make-vector 100 nil))
+ (set (make-local-variable 'overlay-arrow-position) (point-min-marker))
+ (lmc-update-pc)
+ ;; (overwrite-mode 1)
+ (set (make-local-variable 'header-line-format)
+ '("LMC-Sim PC=" (:eval (format "%02d" lmc-pc))
+ " ACC=" (:eval (format "%03d" lmc-acc))
+ " Recent output: "
+ (:eval (if lmc-output (format "%s" lmc-output) "()"))))
+ )
+
+(defun lmc-load (words)
+ (pop-to-buffer "*LMC-Sim*")
+ (lmc-mode)
+ (let ((inhibit-read-only t)
+ (addr 0))
+ (setq lmc-pc 0)
+ (setq lmc-acc 0)
+ (setq lmc-output nil)
+ (erase-buffer)
+ (dolist (word words)
+ (lmc--load-word word addr)
+ (setq addr (1+ addr)))
+ (while (< addr 100)
+ (lmc--load-word '(0) addr)
+ (setq addr (1+ addr))))
+ (lmc-update-pc))
+
+(defvar lmc-store-flash t)
+
+(defun lmc-store-word (addr word)
+ (save-excursion
+ (lmc-addr->point addr)
+ (if (not (re-search-forward "\t.*\t\\(.*\\)$" (line-end-position) t))
+ (error "Missing memory cell %S" addr)
+ (when lmc-store-flash
+ (with-silent-modifications
+ (put-text-property (match-beginning 1) (point)
+ 'face 'region))
+ (sit-for 0.5))
+ (replace-match (format " %03d" word) t t nil 1)
+ (when lmc-store-flash
+ (sit-for 0.1)
+ (with-silent-modifications
+ (put-text-property (match-beginning 1) (point)
+ 'face 'region))
+ (sit-for 0.1)
+ (with-silent-modifications
+ (put-text-property (match-beginning 1) (point)
+ 'face nil))
+ (sit-for 0.1)))))
+
+(defun lmc-step ()
+ "Execute one LMC instruction."
+ (interactive)
+ (let* ((inst (lmc-get-word lmc-pc 'fix))
+ (code (lmc-disassemble-word inst)))
+ (case (car code)
+ (HLT (if (lmc-stopped-p)
+ (error "Already halted")
+ (setq lmc--stopped (lmc--state)) (message "Done.")))
+ (IN (setq lmc-acc (mod (read-number "Enter a number") 1000))
+ (incf lmc-pc))
+ (OUT (message "Output: %03d" lmc-acc)
+ (push (format "%03d" lmc-acc) lmc-output)
+ (incf lmc-pc))
+ (LDA (setq lmc-acc (lmc-get-word (nth 1 code)))
+ (incf lmc-pc))
+ (STO (lmc-store-word (nth 1 code) lmc-acc)
+ (incf lmc-pc))
+ (ADD (setq lmc-acc (mod (+ lmc-acc (lmc-get-word (nth 1 code)))
+ 1000))
+ (incf lmc-pc))
+ (SUB (setq lmc-acc (mod (- lmc-acc (lmc-get-word (nth 1 code)))
+ 1000))
+ (incf lmc-pc))
+ (BR (setq lmc-pc (nth 1 code)))
+ (BRZ (setq lmc-pc (if (zerop lmc-acc)
+ (nth 1 code)
+ (1+ lmc-pc))))
+ (BRP (setq lmc-pc (if (< lmc-acc 500)
+ (nth 1 code)
+ (1+ lmc-pc))))
+ ((nil) (error "Invalid instruction %S" inst))
+ (t (error "%S not implemented" code))))
+ (lmc-update-pc))
+
+;;; The LMC assembly language editor.
+
+(defvar lmc-asm-mode-map
+ (let ((map (make-sparse-keymap)))
+ ;; FIXME: Add "load" and "assemble" buttons.
+ (define-key map "\C-c\C-l" 'lmc-asm-load)
+ (define-key map "\C-c\C-a" 'lmc-asm-assemble)
+ map))
+
+(easy-menu-define lmc-asm-menu lmc-asm-mode-map
+ "Menu for the LMC-Asm mode."
+ '("LMC-Asm"
+ ["Assemble" lmc-asm-assemble]
+ ["Load into Simulator" lmc-asm-load]))
+
+
+(defconst lmc-asm-mnemonic-names
+ (mapcar #'symbol-name
+ (append (mapcar #'car lmc-mnemonic-1-table)
+ (mapcar #'car lmc-mnemonic-0-table)
+ '(DAT))))
+
+(defconst lmc-asm-mnemonic-names-re (regexp-opt lmc-asm-mnemonic-names))
+
+(defvar lmc-asm-font-lock-keywords
+ `(("^[ \t]*\\(?:\\sw\\|\\s_\\)+"
+ (0 (if (zerop (nth 0 (syntax-ppss))) font-lock-constant-face)))
+ (,(concat "(\\(" lmc-asm-mnemonic-names-re "\\_>\\)")
+ (1 font-lock-keyword-face))))
+
+(defvar lmc-asm-imenu-generic-expression
+ '((nil "^\\(\\(?:\\sw\\|\\s_\\)+\\)" 1)))
+
+(defvar lmc-asm-outline-regexp "^\\(?:\\sw\\|\\s_\\)")
+
+;; We use the ".elmc" extension since the syntax is not identical to
+;; the usual ".lmc" syntax.
+;;;###autoload
+(add-to-list 'auto-mode-alist '("\\.elmc\\'" . lmc-asm-mode))
+
+;;;###autoload
+(define-derived-mode lmc-asm-mode fundamental-mode "LMC-Asm"
+ "Major mode to edit LMC assembly code."
+ :syntax-table emacs-lisp-mode-syntax-table
+ (set (make-local-variable 'font-lock-defaults)
+ '(lmc-asm-font-lock-keywords))
+ (set (make-local-variable 'indent-line-function)
+ #'lmc-asm-indent-line)
+ (set (make-local-variable 'indent-tabs-mode) t)
+ (set (make-local-variable 'imenu-generic-expression)
+ lmc-asm-imenu-generic-expression)
+ (set (make-local-variable 'outline-regexp) lmc-asm-outline-regexp)
+ (add-hook 'completion-at-point-functions #'lmc-asm-completion nil t)
+ (set (make-local-variable 'comment-start) ";")
+ (set (make-local-variable 'comment-start-skip)
+ "\\(\\(^\\|[^\\\\\n]\\)\\(\\\\\\\\\\)*\\);+ *")
+ )
+
+(defun lmc-asm-labels (string)
+ (save-excursion
+ ;; We don't want to count the label being completed as a completion
+ ;; candidate, so let's keep track of the original position of point and
+ ;; skip any label nearby.
+ (let ((point (point)))
+ (goto-char (point-min))
+ (let ((ls ())
+ (re (concat "\\(^\\|(" lmc-asm-mnemonic-names-re "[ \t]+" "\\)"
+ (regexp-quote string) "\\(?:\\sw\\|\\s_\\)"
+ (if (> (length string) 0) "*" "+"))))
+ (while (re-search-forward re nil t)
+ (when (or (< point (match-end 1))
+ (> (match-beginning 1) point))
+ (push (buffer-substring-no-properties
+ (match-end 1) (match-end 0)) ls)))
+ ls))))
+
+(defun lmc-asm-completion ()
+ (save-excursion
+ (let ((ppss (syntax-ppss)))
+ (cond
+ ((nth 8 ppss) nil) ;Inside string or comment.
+ ((zerop (nth 0 ppss))
+ (skip-syntax-backward "w_")
+ (when (save-excursion (skip-chars-backward " \t") (bolp))
+ (list (point)
+ (save-excursion (skip-syntax-forward "w_") (point))
+ (completion-table-dynamic #'lmc-asm-labels))))
+ ((= 1 (nth 0 ppss)) ;Inside paren.
+ (skip-syntax-backward "w_")
+ (list (point)
+ (save-excursion (skip-syntax-forward "w_") (point))
+ (if (eq (char-before) ?\()
+ lmc-asm-mnemonic-names
+ (completion-table-dynamic #'lmc-asm-labels))))))))
+
+(defun lmc-asm-indentation ()
+ (save-excursion
+ (back-to-indentation)
+ (cond
+ ((> (nth 0 (syntax-ppss)) 0) nil)
+ ((looking-at "(") tab-width)
+ ((not (looking-at comment-start-skip)) 0)
+ ((not (looking-at "\\s<\\s<")) nil)
+ ((save-excursion (forward-comment (- (point))) (bobp)) 0)
+ (t (forward-comment (point-max)) (lmc-asm-indentation)))))
+
+(defun lmc-asm-indent-line (&optional arg)
+ (let ((indent (lmc-asm-indentation)))
+ (cond
+ ((null indent) (lisp-indent-line arg))
+ (t
+ (let ((left-margin indent)) (indent-to-left-margin))
+ (when (zerop indent)
+ ;; Indent code (if any) after a label.
+ (save-excursion
+ (beginning-of-line)
+ (when (looking-at "\\(?:\\sw\\|\\s_\\)+\\([ \t]*\\)(")
+ (goto-char (match-beginning 1))
+ (if (< (current-column) tab-width)
+ (unless (save-excursion
+ (goto-char (match-end 1))
+ (= (current-column) tab-width))
+ (delete-region (match-beginning 1) (match-end 1))
+ (indent-to tab-width))
+ (unless (equal (match-string 1) " ")
+ (delete-region (match-beginning 1) (match-end 1))
+ (insert " "))))))))))
+
+(defun lmc-asm-read ()
+ (let ((prog ())
+ (initialpos (point)))
+ (goto-char (point-min))
+ (while (progn (forward-comment (point-max))
+ (not (eobp)))
+ (let ((start (point)))
+ (condition-case nil
+ (push (cons (point) (read (current-buffer))) prog)
+ (end-of-file (goto-char start) (signal 'end-of-file nil)))))
+ (goto-char initialpos)
+ (nreverse prog)))
+
+(defun lmc-asm-load ()
+ "Load current buffer into the LMC simluator."
+ (interactive)
+ (let ((initialpos (point))
+ (window (if (eq (current-buffer) (window-buffer)) (selected-window))))
+ (save-current-buffer
+ (lmc-load (lmc--assemble (lmc-asm-read))))
+ (goto-char initialpos)
+ (if (and window (eq (current-buffer) (window-buffer window)))
+ (set-window-point window (point)))))
+
+(defun lmc-asm-assemble ()
+ "Assemble current buffer to check syntax."
+ (interactive)
+ (let ((initialpos (point)))
+ (lmc--assemble (lmc-asm-read))
+ (goto-char initialpos)
+ (message "No errors found")))
+
+(defun lmc-load-file (file)
+ "Load FILE into the LMC simulator."
+ (interactive
+ (list (read-file-name "Load LMC file: " nil nil t nil
+ (lambda (file)
+ (or (file-directory-p file)
+ (string-match-p "\\.elmc\\'" file))))))
+ (let ((exists (find-buffer-visiting file))
+ (buf (find-file-noselect file)))
+ (unwind-protect
+ (with-current-buffer buf
+ (condition-case err
+ (lmc-asm-load)
+ (error (error "Error at line %d: %s" (line-number-at-pos)
+ (error-message-string err)))))
+ (unless exists (kill-buffer buf)))))
+
+(provide 'lmc)
+;;; lmc.el ends here