;;; simula.el --- SIMULA 87 code editing commands for Emacs

;; Copyright (C) 1992, 1994, 1996, 2001-2017 Free Software Foundation,
;; Inc.

;; Author: Hans Henrik Eriksen <hhe@ifi.uio.no>
;; Maintainer: simula-mode@ifi.uio.no
;;   (above email addresses invalid as of April 2008)
;; Adapted-By: ESR
;; Keywords: languages

;; This file is part of GNU Emacs.

;; GNU Emacs 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.

;; GNU Emacs 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 GNU Emacs.  If not, see <http://www.gnu.org/licenses/>.

;;; Commentary:

;; A major mode for editing the Simula language.  It knows about Simula
;; syntax and standard indentation commands.  It also provides convenient
;; abbrevs for Simula keywords.
;;
;; Hans Henrik Eriksen (the author) may be reached at:
;;         Institutt for informatikk,
;;         Universitetet i Oslo

;;; Code:


(defgroup simula nil
  "Major mode for editing Simula code."
  :link '(custom-group-link :tag "Font Lock Faces group" font-lock-faces)
  :prefix "simula-"
  :group 'languages)

(defconst simula-tab-always-indent-default nil
  "Non-nil means TAB in SIMULA mode should always reindent the current line.
Otherwise TAB indents only when point is within
the run of whitespace at the beginning of the line.")

(defcustom simula-tab-always-indent simula-tab-always-indent-default
  "Non-nil means TAB in SIMULA mode should always reindent the current line.
Otherwise TAB indents only when point is within
the run of whitespace at the beginning of the line."
  :type 'boolean
  :group 'simula)

(defconst simula-indent-level-default 3
  "Indentation of SIMULA statements with respect to containing block.")

(defcustom simula-indent-level simula-indent-level-default
  "Indentation of SIMULA statements with respect to containing block."
  :type 'integer
  :group 'simula)


(defconst simula-substatement-offset-default 3
  "Extra indentation after DO, THEN, ELSE, WHEN and OTHERWISE.")

(defcustom simula-substatement-offset simula-substatement-offset-default
  "Extra indentation after DO, THEN, ELSE, WHEN and OTHERWISE."
  :type 'integer
  :group 'simula)

(defconst simula-continued-statement-offset-default 3
  "Extra indentation for lines not starting a statement or substatement.
If value is a list, each line in a multipleline continued statement
will have the car of the list extra indentation with respect to
the previous line of the statement.")

(defcustom simula-continued-statement-offset
  simula-continued-statement-offset-default
  "Extra indentation for lines not starting a statement or substatement.
If value is a list, each line in a multipleline continued statement
will have the car of the list extra indentation with respect to
the previous line of the statement."
  :type 'integer
  :group 'simula)

(defconst simula-label-offset-default -4711
  "Offset of SIMULA label lines relative to usual indentation.")

(defcustom simula-label-offset simula-label-offset-default
  "Offset of SIMULA label lines relative to usual indentation."
  :type 'integer
  :group 'simula)

(defconst simula-if-indent-default '(0 . 0)
  "Extra indentation of THEN and ELSE with respect to the starting IF.
Value is a cons cell, the car is extra THEN indentation and the cdr
extra ELSE indentation.  IF after ELSE is indented as the starting IF.")

(defcustom simula-if-indent simula-if-indent-default
  "Extra indentation of THEN and ELSE with respect to the starting IF.
Value is a cons cell, the car is extra THEN indentation and the cdr
extra ELSE indentation.  IF after ELSE is indented as the starting IF."
  :type '(cons integer integer)
  :group 'simula)

(defconst simula-inspect-indent-default '(0 . 0)
  "Extra indentation of WHEN and OTHERWISE with respect to the INSPECT.
Value is a cons cell, the car is extra WHEN indentation
and the cdr extra OTHERWISE indentation.")

(defcustom simula-inspect-indent simula-inspect-indent-default
  "Extra indentation of WHEN and OTHERWISE with respect to the INSPECT.
Value is a cons cell, the car is extra WHEN indentation
and the cdr extra OTHERWISE indentation."
  :type '(cons integer integer)
  :group 'simula)

(defconst simula-electric-indent-default nil
  "Non-nil means `simula-indent-line' function may reindent previous line.")

(defcustom simula-electric-indent simula-electric-indent-default
  "Non-nil means `simula-indent-line' function may reindent previous line."
  :type 'boolean
  :group 'simula)

(defconst simula-abbrev-keyword-default 'upcase
  "Specify how to convert case for SIMULA keywords.
Value is one of the symbols `upcase', `downcase', `capitalize',
\(as in) `abbrev-table' or nil if they should not be changed.")

(defcustom simula-abbrev-keyword simula-abbrev-keyword-default
  "Specify how to convert case for SIMULA keywords.
Value is one of the symbols `upcase', `downcase', `capitalize',
\(as in) `abbrev-table' or nil if they should not be changed."
  :type '(choice (const upcase) (const downcase) (const capitalize)(const nil))
  :group 'simula)

(defconst simula-abbrev-stdproc-default 'abbrev-table
  "Specify how to convert case for standard SIMULA procedure and class names.
Value is one of the symbols `upcase', `downcase', `capitalize',
\(as in) `abbrev-table', or nil if they should not be changed.")

(defcustom simula-abbrev-stdproc simula-abbrev-stdproc-default
  "Specify how to convert case for standard SIMULA procedure and class names.
Value is one of the symbols `upcase', `downcase', `capitalize',
\(as in) `abbrev-table', or nil if they should not be changed."
  :type '(choice (const upcase) (const downcase) (const capitalize)
	  (const abbrev-table) (const nil))
  :group 'simula)

(defcustom simula-abbrev-file nil
  "File with extra abbrev definitions for use in SIMULA mode.
These are used together with the standard abbrev definitions for SIMULA.
Please note that the standard definitions are required
for SIMULA mode to function correctly."
  :type '(choice file (const nil))
  :group 'simula)

(defvar simula-mode-syntax-table nil
  "Syntax table in SIMULA mode buffers.")

(defconst simula-syntax-propertize-function
  (syntax-propertize-rules
   ;; `comment' directive.
   ("\\<\\(c\\)omment\\>" (1 "<"))
   ;; end comments
   ((concat "\\<end\\>\\([^;\n]\\).*?\\(\n\\|\\(.\\)\\(;\\|"
            (regexp-opt '("end" "else" "when" "otherwise"))
            "\\)\\)")
    (1 "< b")
    (3 "> b"))
   ;; non-quoted single-quote char.
   ("'\\('\\)'" (1 "."))))

;; Regexps written with help from Alf-Ivar Holm <alfh@ifi.uio.no>.
(defconst simula-font-lock-keywords-1
  '(;;
    ;; Compiler directives.
    ("^%\\([^ \t\n].*\\)" 1 font-lock-constant-face t)
    ;;
    ;; Class and procedure names.
    ("\\<\\(class\\|procedure\\)\\>[ \t]*\\(\\sw+\\)?"
     (1 font-lock-keyword-face) (2 font-lock-function-name-face nil t)))
  "Subdued level highlighting for Simula mode.")

(defconst simula-font-lock-keywords-2
  (append simula-font-lock-keywords-1
   (list
    ;;
    ;; Constants.
    '("\\<\\(false\\|none\\|notext\\|true\\)\\>" . font-lock-constant-face)
    ;;
    ;; Keywords.
    (regexp-opt
     '("activate" "after" "and" "at" "before" "begin" "delay" "do"
       "else" "end" "eq" "eqv" "external" "for" "ge" "go" "goto" "gt"
       "hidden" "if" "imp" "in" "inner" "inspect" "is" "label" "le"
       "lt" "ne" "new" "not" "or" "otherwise" "prior" "protected"
       "qua" "reactivate" "step" "switch" "then" "this" "to" "until"
       "virtual" "when" "while") 'words)
    ;;
    ;; Types.
    (cons (regexp-opt
	   '("array" "boolean" "character" "integer"
	     "long" "name" "real" "short" "text" "value" "ref") 'words)
	  'font-lock-type-face)))
  "Medium level highlighting for Simula mode.")

(defconst simula-font-lock-keywords-3
  (append simula-font-lock-keywords-2
   (list
    ;;
    ;; Super-class names and super-slow.
    '("\\<\\(\\sw+\\)[ \t]+class\\>" 1 font-lock-function-name-face)
    ;;
    ;; Types and their declarations.
    (list (concat "\\<\\(array\\|boolean\\|character\\|integer\\|"
		  "long\\|name\\|real\\|short\\|text\\|value\\)\\>"
		  "\\([ \t]+\\sw+\\>\\)*")
	  '(font-lock-match-c-style-declaration-item-and-skip-to-next
	    ;; Start with point after all type specifiers.
	    (goto-char (or (match-beginning 2) (match-end 1)))
	    ;; Finish with point after first type specifier.
	    (goto-char (match-end 1))
	    ;; Fontify as a variable name.
	    (1 font-lock-variable-name-face)))
    ;;
    ;; Object references and their declarations.
    '("\\<\\(ref\\)\\>[ \t]*\\((\\(\\sw+\\))\\)?"
      (3 font-lock-function-name-face nil t)
      (font-lock-match-c-style-declaration-item-and-skip-to-next nil nil
       (1 font-lock-variable-name-face)))
    ))
  "Gaudy level highlighting for Simula mode.")

(defvar simula-font-lock-keywords simula-font-lock-keywords-1
  "Default expressions to highlight in Simula mode.")

; The following function is taken from cc-mode.el,
; it determines the flavor of the Emacs running

(defvar simula-mode-menu
  '(["Indent Line"	      simula-indent-line t]
    ["Backward Statement"     simula-previous-statement t]
    ["Forward Statement"      simula-next-statement t]
    ["Backward Up Level"      simula-backward-up-level t]
    ["Forward Down Statement" simula-forward-down-level t])
  "Lucid Emacs menu for SIMULA mode.")

(if simula-mode-syntax-table
    ()
  (setq simula-mode-syntax-table (copy-syntax-table (standard-syntax-table)))
  (modify-syntax-entry ?!  "<"    simula-mode-syntax-table)
  (modify-syntax-entry ?$  "."    simula-mode-syntax-table)
  (modify-syntax-entry ?%  "< b"  simula-mode-syntax-table)
  (modify-syntax-entry ?\n "> b"  simula-mode-syntax-table)
  (modify-syntax-entry ?'  "\""   simula-mode-syntax-table)
  (modify-syntax-entry ?\( "()"   simula-mode-syntax-table)
  (modify-syntax-entry ?\) ")("   simula-mode-syntax-table)
  (modify-syntax-entry ?\; ">"    simula-mode-syntax-table)
  (modify-syntax-entry ?\[ "."    simula-mode-syntax-table)
  (modify-syntax-entry ?\\ "."    simula-mode-syntax-table)
  (modify-syntax-entry ?\] "."    simula-mode-syntax-table)
  (modify-syntax-entry ?_  "_"    simula-mode-syntax-table)
  (modify-syntax-entry ?\| "."    simula-mode-syntax-table)
  (modify-syntax-entry ?\{ "."    simula-mode-syntax-table)
  (modify-syntax-entry ?\} "."    simula-mode-syntax-table))

(defvar simula-mode-map
  (let ((map (make-sparse-keymap)))
    (define-key map "\C-c\C-u"   'simula-backward-up-level)
    (define-key map "\C-c\C-p"   'simula-previous-statement)
    (define-key map "\C-c\C-d"   'simula-forward-down-level)
    (define-key map "\C-c\C-n"   'simula-next-statement)
    ;; (define-key map "\C-c\C-g"   'simula-goto-definition)
    ;; (define-key map "\C-c\C-h"   'simula-standard-help)
    (define-key map "\177"       'backward-delete-char-untabify)
    (define-key map ":"          'simula-electric-label)
    (define-key map "\e\C-q"     'simula-indent-exp)
    (define-key map "\t"         'simula-indent-command)
    ;; Emacs 19 defines menus in the mode map
    (define-key map [menu-bar simula]
      (cons "SIMULA" (make-sparse-keymap "SIMULA")))
    (define-key map [menu-bar simula indent-exp]
      '("Indent Expression" . simula-indent-exp))
    (define-key map [menu-bar simula indent-line]
      '("Indent Line" . simula-indent-command))
    (define-key map [menu-bar simula separator-navigate]
      '("--"))
    (define-key map [menu-bar simula backward-stmt]
      '("Previous Statement" . simula-previous-statement))
    (define-key map [menu-bar simula forward-stmt]
      '("Next Statement" . simula-next-statement))
    (define-key map [menu-bar simula backward-up]
      '("Backward Up Level" . simula-backward-up-level))
    (define-key map [menu-bar simula forward-down]
      '("Forward Down Statement" . simula-forward-down-level))

    (put 'simula-next-statement 'menu-enable '(not (eobp)))
    (put 'simula-previous-statement 'menu-enable '(not (bobp)))
    (put 'simula-forward-down-level 'menu-enable '(not (eobp)))
    (put 'simula-backward-up-level 'menu-enable '(not (bobp)))
    (put 'simula-indent-command 'menu-enable '(not buffer-read-only))
    (put 'simula-indent-exp 'menu-enable '(not buffer-read-only))

    ;; RMS: mouse-3 should not select this menu.  mouse-3's global
    ;; definition is useful in SIMULA mode and we should not interfere
    ;; with that.  The menu is mainly for beginners, and for them,
    ;; the menubar requires less memory than a special click.
    ;; in Lucid Emacs, we want the menu to popup when the 3rd button is
    ;; hit.  In 19.10 and beyond this is done automatically if we put
    ;; the menu on mode-popup-menu variable, see c-common-init [cc-mode.el]
    ;;(if (not (boundp 'mode-popup-menu))
    ;;	(define-key simula-mode-map 'button3 'simula-popup-menu))
    map)
  "Keymap used in `simula-mode'.")

;; menus for Lucid
(defun simula-popup-menu (_e)
  "Pops up the SIMULA menu."
  (interactive "@e")
  (popup-menu (cons (concat mode-name " Mode Commands") simula-mode-menu)))

;;;###autoload
(define-derived-mode simula-mode prog-mode "Simula"
  "Major mode for editing SIMULA code.
\\{simula-mode-map}
Variables controlling indentation style:
 `simula-tab-always-indent'
    Non-nil means TAB in SIMULA mode should always reindent the current line,
    regardless of where in the line point is when the TAB command is used.
 `simula-indent-level'
    Indentation of SIMULA statements with respect to containing block.
 `simula-substatement-offset'
    Extra indentation after DO, THEN, ELSE, WHEN and OTHERWISE.
 `simula-continued-statement-offset' 3
    Extra indentation for lines not starting a statement or substatement,
    e.g. a nested FOR-loop.  If value is a list, each line in a multiple-
    line continued statement will have the car of the list extra indentation
    with respect to the previous line of the statement.
 `simula-label-offset' -4711
    Offset of SIMULA label lines relative to usual indentation.
 `simula-if-indent' (0 . 0)
    Extra indentation of THEN and ELSE with respect to the starting IF.
    Value is a cons cell, the car is extra THEN indentation and the cdr
    extra ELSE indentation.  IF after ELSE is indented as the starting IF.
 `simula-inspect-indent' (0 . 0)
    Extra indentation of WHEN and OTHERWISE with respect to the
    corresponding INSPECT.  Value is a cons cell, the car is
    extra WHEN indentation and the cdr extra OTHERWISE indentation.
 `simula-electric-indent' nil
    If this variable is non-nil, `simula-indent-line'
    will check the previous line to see if it has to be reindented.
 `simula-abbrev-keyword' `upcase'
    Determine how SIMULA keywords will be expanded.  Value is one of
    the symbols `upcase', `downcase', `capitalize', (as in) `abbrev-table',
    or nil if they should not be changed.
 `simula-abbrev-stdproc' `abbrev-table'
    Determine how standard SIMULA procedure and class names will be
    expanded.  Value is one of the symbols `upcase', `downcase', `capitalize',
    (as in) `abbrev-table', or nil if they should not be changed.

Turning on SIMULA mode calls the value of the variable simula-mode-hook
with no arguments, if that value is non-nil."
  (set (make-local-variable 'comment-column) 40)
  ;; (set (make-local-variable 'end-comment-column) 75)
  (set (make-local-variable 'paragraph-start) "[ \t]*$\\|\\f")
  (set (make-local-variable 'paragraph-separate) paragraph-start)
  (set (make-local-variable 'indent-line-function) 'simula-indent-line)
  (set (make-local-variable 'comment-start) "! ")
  (set (make-local-variable 'comment-end) " ;")
  (set (make-local-variable 'comment-start-skip) "!+ *")
  (set (make-local-variable 'parse-sexp-ignore-comments) nil)
  (set (make-local-variable 'comment-multi-line) t)
  (set (make-local-variable 'font-lock-defaults)
       '((simula-font-lock-keywords simula-font-lock-keywords-1
          simula-font-lock-keywords-2 simula-font-lock-keywords-3)
         nil t ((?_ . "w"))))
  (set (make-local-variable 'syntax-propertize-function)
       simula-syntax-propertize-function)
  (abbrev-mode 1))

(defun simula-indent-exp ()
  "Indent SIMULA expression following point."
  (interactive)
  (let ((here (point))
	(simula-electric-indent nil)
	end)
    (simula-skip-comment-forward)
    (if (eobp)
	(goto-char here)
      (unwind-protect
	  (progn
	    (simula-next-statement 1)
	    (setq end (point-marker))
	    (simula-previous-statement 1)
	    (beginning-of-line)
	    (while (< (point) end)
	      (if (not (looking-at "[ \t]*$"))
		  (simula-indent-line))
	      (forward-line 1)))
	(and end (set-marker end nil))))))


(defun simula-indent-line ()
  "Indent this line as SIMULA code.
If `simula-electric-indent' is non-nil, indent previous line if necessary."
  (let ((origin (- (point-max) (point)))
	(indent (simula-calculate-indent))
	(case-fold-search t))
    (unwind-protect
	(if simula-electric-indent
	    (progn
	      ;;
	      ;; manually expand abbrev on last line, if any
	      ;;
	      (end-of-line 0)
	      (expand-abbrev)
	      ;; now maybe we should reindent that line
	      (beginning-of-line)
	      (skip-chars-forward " \t\f")
	      (if (and
		   (looking-at
		    "\\(end\\|if\\|then\\|else\\|when\\|otherwise\\)\\>")
		   (not (simula-context)))
		  ;; yes - reindent
		  (let ((post-indent (simula-calculate-indent)))
		    (if (eq (current-indentation) post-indent)
			()
		      (delete-horizontal-space)
		      (indent-to post-indent))))))
      (goto-char (- (point-max) origin))
      (if (eq (current-indentation) indent)
	  (back-to-indentation)
	(delete-horizontal-space)
	(indent-to indent)))))


(defun simula-indent-command (&optional whole-exp)
  "Indent current line as SIMULA code, or insert TAB character.
If `simula-tab-always-indent' is non-nil, always indent current line.
Otherwise, indent only if point is before any non-whitespace
character on the line.

A numeric argument, regardless of its value, means indent rigidly
all the lines of the SIMULA statement after point so that this line
becomes properly indented.
The relative indentation among the lines of the statement are preserved."
  (interactive "P")
  (let ((case-fold-search t))
    (if (or whole-exp simula-tab-always-indent
	    (save-excursion
	      (skip-chars-backward " \t\f")
	      (bolp)))
	;; reindent current line
	(let ((indent (save-excursion
			(beginning-of-line)
			(simula-calculate-indent)))
	      (current (current-indentation))
	      (origin (- (point-max) (point)))
	      (bol (save-excursion
		     (skip-chars-backward " \t\f")
		     (bolp)))
	      beg end)
	  (unwind-protect
	      (if (eq current indent)
		  (if (save-excursion
			(skip-chars-backward " \t\f")
			(bolp))
		      (back-to-indentation))
		(beginning-of-line)
		(delete-horizontal-space)
		(indent-to indent))
	    (if (not bol)
		(goto-char (- (point-max) origin))))
	  (setq origin (point))
	  (if whole-exp
	      (save-excursion
		(beginning-of-line 2)
		(setq beg (point))
		(goto-char origin)
		(simula-next-statement 1)
		(setq end (point))
		(if (and (> end beg) (not (eq indent current)))
		    (indent-code-rigidly beg end (- indent current) "%")))))
      (insert-tab))))


(defun simula-context ()
  "Return value according to syntactic SIMULA context of point.
    0    point inside COMMENT comment
    1    point on SIMULA-compiler directive line
    2    point inside END comment
    3    point inside string
    4    point inside character constant
  nil    otherwise."
  ;; first, find out if this is a compiler directive line
  (if (save-excursion
	(beginning-of-line)
	(eq (following-char) ?%))
      ;; YES - return 1
      1
    (save-excursion
      ;; The current line is NOT a compiler directive line.
      ;; Now, the strategy is to search backward to find a semicolon
      ;; that is NOT inside a string. The point after semicolon MUST be
      ;; outside a comment, since semicolons are comment-ending and
      ;; comments are non-recursive. We take advantage of the fact
      ;; that strings MUST end on the same line as they started, so
      ;; that we can easily decide whether we are inside a string or not.
      (let (return-value (origin (point)))
	(skip-chars-backward "^;" (point-min))
	;; found semicolon or beginning of buffer
	(let (loopvalue (saved-point origin))
	  (while (and (not (bobp))
		      (if (progn
			    (beginning-of-line)
			    ;; compiler directive line? If so, cont searching..
			    (eq (following-char) ?%))
			  t
			(while (< (point) saved-point)
			  (skip-chars-forward "^;\"'")
			  (forward-char 1)
			  (cond
			   ((eq (preceding-char) ?\;)
			    (setq saved-point (point)))
			   ((eq (preceding-char) ?\")
			    (skip-chars-forward "^\";")
			    (if (eq (following-char) ?\;)
				(setq saved-point (point) loopvalue t)
			      (forward-char 1)))
			   (t
			    (if (eq (following-char) ?')
				(forward-char 1))
			    (skip-chars-forward "^';")
			    (if (eq (following-char) ?\;)
				(setq saved-point (point) loopvalue t)
			      (forward-char 1)))))
			loopvalue))
	    (backward-char 1)
	    (skip-chars-backward "^;")
	    (setq saved-point (point) loopvalue nil)))
	;; Now we are CERTAIN that we are outside comments and strings.
	;; The job now is to search forward again towards the origin
	;; skipping directives, comments and strings correctly,
	;; so that we know what context we are in when we find the origin.
	(while (and
		(< (point) origin)
		(re-search-forward
		 "\\<end\\>\\|!\\|\"\\|'\\|^%\\|\\<comment\\>" origin 'move))
	  (cond
	   ((memq (preceding-char) '(?d ?D))
	    (setq return-value 2)
	    (while (and (re-search-forward
			 ";\\|\\<end\\>\\|\\<else\\>\\|\\<otherwise\\>\\|\\<when\\>\\|^%"
			 origin 'move)
			;; found another END?
			(or (memq (preceding-char) '(?d ?D))
			    ;; if directive, skip line
			    (and (eq (preceding-char) ?%)
				 (beginning-of-line 2))
			    ;; found other keyword, out of END comment
			    (setq return-value nil))))
	    (if (and (eq (char-syntax (preceding-char)) ?w)
		     (eq (char-syntax (following-char)) ?w))
		(save-excursion
		  (backward-word-strictly 1)
		  (if (looking-at "end\\>\\|else\\>\\|otherwise\\>\\|when\\>")
		      (setq return-value nil)))))
	   ((memq (preceding-char) '(?! ?t ?T))
	    ; skip comment
	    (setq return-value 0)
	    (skip-chars-forward "^%;" origin)
	    (while (and return-value (< (point) origin))
	      (if (eq (following-char) ?\;)
		  (setq return-value nil)
		(if (bolp)
		    (beginning-of-line 2)	; skip directive inside comment
		  (forward-char 1))		; or single '%'
		(skip-chars-forward "^%;" origin))))
	   ((eq (preceding-char) ?\")
	    (if (not (search-forward "\"" origin 'move))
		(setq return-value 3)))
	   ((eq (preceding-char) ?\')
	    (if (or (eq (point) origin) (eobp))
		(setq return-value 4)
	      (forward-char 1)
	      (if (not (search-forward "'" origin 'move))
		  (setq return-value 4))))
	   ;; compiler directive line - skip
	   (t (beginning-of-line 2))))
	return-value)
      )))


(defun simula-electric-label ()
  "If this is a label that starts the line, reindent the line."
  (interactive)
  (expand-abbrev)
  (insert ?:)
  (let ((origin (- (point-max) (point)))
	(case-fold-search t)
	;; don't mix a label with an assignment operator := :-
	;; therefore take a peek at next typed character...
	(next-char (read-event)))
    (unwind-protect
	(setq unread-command-events (append unread-command-events
					    (list next-char)))
	;; Problem: find out if character just read is a command char
	;; that would insert something after ':' making it a label.
	;; At least \n, \r (and maybe \t) falls into this category.
	;; This is a real crock, it depends on traditional keymap
	;; bindings, that is, printing characters doing self-insert,
	;; and no other command sequence inserting '-' or '='.
	;; simula-electric-label can be easily fooled...
	(if (and (not (memq next-char '(?= ?-)))
		 (or (memq next-char '(?\n ?\r))
		     (and (eq next-char ?\t)
			  simula-tab-always-indent)
		     (not (memq (following-char) '(?= ?-))))
		 (not (simula-context))
		 ;; label?
		 (progn
		   (backward-char 1)
		   (skip-chars-backward " \t\f")
		   (skip-chars-backward "a-zA-Z0-9_")
		   (if (looking-at "virtual\\>")
		       nil
		     (skip-chars-backward " \t\f")
		     (bolp))))
	    (let ((amount (simula-calculate-indent)))
	      (delete-horizontal-space)
	      (indent-to amount)))
      (goto-char (- (point-max) origin)))))


(defun simula-backward-up-level (count)
  "Move backward up COUNT block levels.
If COUNT is negative, move forward up block level instead."
  (interactive "p")
  (let ((origin (point))
	(case-fold-search t))
    (condition-case ()
	(if (> count 0)
	    (while (> count 0)
	      (re-search-backward "\\<begin\\>\\|\\<end\\>")
	      (if (not (simula-context))
		  (setq count (if (memq (following-char) '(?b ?B))
				  (1- count)
				(1+ count)))))
	  (while (< count 0)
	    (re-search-forward "\\<begin\\>\\|\\<end\\>")
	    (backward-word-strictly 1)
	    (if (not (simula-context))
		(setq count (if (memq (following-char) '(?e ?E))
				(1+ count)
			      (1- count))))
	    (backward-word-strictly -1)))
      ;; If block level not found, jump back to origin and signal an error
      (error (progn
	       (goto-char origin)
	       (error "No higher block level")))
      (quit (progn
	      (goto-char origin)
	      (signal 'quit nil))))))


(defun simula-forward-down-level (count)
  "Move forward down COUNT block levels.
If COUNT is negative, move backward down block level instead."
  (interactive "p")
  ;; When we search for a deeper block level, we must never
  ;; get out of the block where we started -> count >= start-count
  (let ((start-count count)
	(origin (point))
	(case-fold-search t))
    (condition-case ()
	(if (< count 0)
	    (while (< count 0)
	      (re-search-backward "\\<begin\\>\\|\\<end\\>")
	      (if (not (simula-context))
		  (setq count (if (memq (following-char) '(?e ?E))
				  (1+ count)
				(1- count))))
	      (if (< count start-count) (signal 'error nil)))
	  (while (> count 0)
	    (re-search-forward "\\<begin\\>\\|\\<end\\>")
	    (backward-word-strictly 1)
	    (if (not (simula-context))
		(setq count (if (memq (following-char) '(?b ?B))
				(1- count)
			      (1+ count))))
	    (backward-word-strictly -1)
	    ;; deeper level has to be found within starting block
	    (if (> count start-count) (signal 'error nil))))
      ;; If block level not found, jump back to origin and signal an error
      (error (progn
	       (goto-char origin)
	       (error "No containing block level")))
      (quit (progn
	      (goto-char origin)
	      (signal 'quit nil))))))


(defun simula-previous-statement (count)
  "Move backward COUNT statements.
If COUNT is negative, move forward instead."
  (interactive "p")
  (if (< count 0)
      (simula-next-statement (- count))
    (let (status
	  (case-fold-search t)
	  (origin (point)))
      (condition-case ()
	  ;;
	  (progn
	    (simula-skip-comment-backward)
	    (if (memq (preceding-char) '(?n ?N))
		(progn
		  (backward-word-strictly 1)
		  (if (not (looking-at "\\<begin\\>"))
		      (backward-word-strictly -1)))
	      (if (eq (preceding-char) ?\;)
		  (backward-char 1))
	      )
	    (while (and (natnump (setq count (1- count)))
			(setq status (simula-search-backward
				      ";\\|\\<begin\\>" nil 'move))))
	    (if status
		(progn
		  (if (eq (following-char) ?\;)
		      (forward-char 1)
		    (backward-word-strictly -1))))
	    (simula-skip-comment-forward))
	(error (progn (goto-char origin)
		      (error "Incomplete statement (too many ENDs)")))
	(quit (progn (goto-char origin) (signal 'quit nil)))))))


(defun simula-next-statement (count)
  "Move forward COUNT statements.
If COUNT is negative, move backward instead."
  (interactive "p")
  (if (< count 0)
      (simula-previous-statement (- count))
    (let (status
	  (case-fold-search t)
	  (origin (point)))
      (condition-case ()
	  (progn
	    (simula-skip-comment-forward)
	    (if (looking-at "\\<end\\>") (forward-word-strictly 1))
	    (while (and (natnump (setq count (1- count)))
			(setq status (simula-search-forward
				      ";\\|\\<end\\>" (point-max) 'move))))
	    (if (and status (/= (preceding-char) ?\;))
		(progn
		  (backward-word-strictly 1)
		  (simula-skip-comment-backward))))
	(error (progn (goto-char origin)
		      (error "Incomplete statement (too few ENDs)")))
 	(quit (progn (goto-char origin) (signal 'quit nil)))))))


(defun simula-skip-comment-backward (&optional stop-at-end)
  "Search towards bob to find first char that is outside a comment."
  (interactive)
  (catch 'simula-out
    (let (context)
      (while t
	(skip-chars-backward " \t\n\f")
	(if (eq (preceding-char) ?\;)
	    (save-excursion
	      (backward-char 1)
	      (setq context (simula-context))
	      (if (and stop-at-end (eq context 2))
		  (setq context nil)))
	  (setq context (simula-context)))
	(cond
	 ((memq context '(nil 3 4))
	  ;; check to see if we found a label
	  (if (and (eq (preceding-char) ?:)
		   (not (memq (following-char) '(?- ?=)))
		   (save-excursion
		     (skip-chars-backward ": \t\fa-zA-Z0-9_")
		     (not (looking-at "virtual\\>"))))
	      (skip-chars-backward ": \t\fa-zA-Z0-9_")
	    (throw 'simula-out nil)))
	 ((eq context 0)
	  ;; since we are inside a comment, it must start somewhere!
	  (while (and (re-search-backward "!\\|\\<comment\\>")
		      (memq (simula-context) '(0 1)))))
	 ((eq context 1)
	  (beginning-of-line)
	  (if (bobp)
	      (throw 'simula-out nil)
	    (backward-char)))
	 ((eq context 2)
	  ;; an END-comment must belong to an END
	  (re-search-backward "\\<end\\>")
	  (forward-word-strictly 1)
	  (throw 'simula-out nil))
	 ;; should be impossible to get here..
	 )))))


(defun simula-skip-comment-forward ()
  "Search towards eob to find first char that is outside a comment."
  ;; this function assumes we start with point .outside a comment
  (interactive)
  (catch 'simula-out
    (while t
      (skip-chars-forward " \t\n\f")
      ;; BUG: the following (0 2) branches don't take into account intermixing
      ;; directive lines
      (cond
       ((looking-at "!\\|\\<comment\\>")
	(search-forward ";" nil 'move))
       ((and (bolp) (eq (following-char) ?%))
	(beginning-of-line 2))
       ((and (looking-at "[a-z0-9_]*[ \t\f]*:[^-=]")
	     (not (looking-at "virtual\\>")))
	(skip-chars-forward "a-zA-Z0-9_ \t\f:"))
       (t
	(throw 'simula-out t))))))


(defun simula-forward-up-level ()
  (let ((continue-loop t)
	(origin (point))
	(case-fold-search t)
	return-value
	temp)
    (while continue-loop
      (if (re-search-backward "\\<begin\\>\\|\\<end\\>" (point-min) 'move)
	  (setq temp (simula-context)
	      return-value (and (memq (preceding-char) '(?d ?D))
				(memq temp '(nil 2)))
	      continue-loop (and (not return-value)
				 (simula-forward-up-level)))
	(setq continue-loop nil)))
    (if return-value
	t
      (goto-char origin)
      nil)))


(defun simula-calculate-indent ()
  (save-excursion
    (let ((where (simula-context))
	  (origin (point))
	  (indent 0)
	  continued
	  start-line
	  temp
	  found-end
	  prev-cont)
      (cond
       ((eq where 0)
	;;
	;; Comment.
	;; If comment started on previous non-blank line, indent to the
	;; column where the comment started, else indent as that line.
	;;
	(skip-chars-backward " \t\n\f")
	(while (and (not (bolp)) (eq (simula-context) 0))
	  (re-search-backward "^\\|!\\|\\<comment\\>"))
	(skip-chars-forward " \t\n\f")
	(prog1
	    (current-column)
	  (goto-char origin)))
       ((eq where 1)
	;;
	;; Directive. Always 0.
	;;
	0)
       ;;
       ;; Detect missing string delimiters
       ;;
       ((eq where 3)
	(error "Inside string"))
       ((eq where 4)
	(error "Inside character constant"))
       ;;
       ;; check to see if inside ()'s
       ;;
       ((setq temp (simula-inside-parens))
	temp)
       ;;
       ;; Calculate non-comment indentation
       (t
	;; first, find out if this line starts with something that needs
	;; special indentation (END/IF/THEN/ELSE/WHEN/OTHERWISE or label)
	;;
	(skip-chars-forward " \t\f")
	(cond
	 ;;
	 ;; END
	 ;;
	 ((looking-at "end\\>")
	  (setq indent (- simula-indent-level)
		found-end t))
	 ;;
	 ;; IF/THEN/ELSE
	 ;;
	 ((looking-at "if\\>\\|then\\>\\|else\\>")
	  ;; search for the *starting* IF
	  (cond
	   ((memq (following-char) '(?T ?t))
	    (setq indent (car simula-if-indent)))
	   ((memq (following-char) '(?E ?e))
	    (setq indent (cdr simula-if-indent)))
	   (t
	    (forward-word-strictly 1)
	    (setq indent 0)))
	  (simula-find-if))
	 ;;
	 ;; WHEN/OTHERWISE
	 ;;
	 ((looking-at "when\\>\\|otherwise\\>")
	  ;; search for corresponding INSPECT
	  (if (memq (following-char) '(?W ?w))
	      (setq indent (car simula-inspect-indent))
	    (setq indent (cdr simula-inspect-indent)))
	  (simula-find-inspect))
	 ;;
	 ;; label:
	 ;;
	 ((and (not (looking-at "virtual\\>"))
	       (looking-at "[a-z0-9_]*[ \t\f]*:[^-=]"))
	  (setq indent simula-label-offset)))
	;; find line with non-comment text
	(simula-skip-comment-backward 'dont-skip-end)
	(if (and found-end
		 (not (eq (preceding-char) ?\;))
		 (if (memq (preceding-char) '(?N ?n))
		     (save-excursion
		       (backward-word-strictly 1)
		       (not (looking-at "begin\\>")))
		   t))
	    (progn
	      (simula-previous-statement 1)
	      (simula-skip-comment-backward)))
	(setq start-line
	      (line-beginning-position)
	      ;; - perhaps this is a continued statement
	      continued
	      (save-excursion
		(and (not (bobp))
		     ;; (not found-end)
		     (if (eq (char-syntax (preceding-char)) ?w)
			 (progn
			   (backward-word-strictly 1)
			   (not (looking-at
				 "begin\\|then\\|else\\|when\\|otherwise\\|do"
				 )))
		       (not (memq (preceding-char) '(?: ?\;)))))))
	;;
	;; MAIN calculation loop - count BEGIN/DO etc.
	;;
	(while (not (bolp))
	  (if (re-search-backward
	       ";\\|\\<\\(begin\\|end\\|if\\|else\\|then\\|when\\|otherwise\\|do\\)\\>"
	       start-line 'move)
	      (if (simula-context)
		  ();; found something in a comment/string - ignore
		(setq temp (following-char))
		(cond
		 ((eq temp ?\;)
		  (simula-previous-statement 1))
		 ((looking-at "begin\\>")
		  (setq indent (+ indent simula-indent-level)))
		 ((looking-at "end\\>")
		  (forward-word-strictly 1)
		  (simula-previous-statement 1))
		 ((looking-at "do\\>")
		  (setq indent (+ indent simula-substatement-offset))
		  (simula-find-do-match))
		 ((looking-at "\\(if\\|then\\|else\\)\\>")
		  (if (memq temp '(?I ?i))
		      (forward-word-strictly 1)
		    (setq indent (+ indent
				    simula-substatement-offset
				    (if (memq temp '(?T ?t))
					(car simula-if-indent)
				      (cdr simula-if-indent)))))
		  (simula-find-if))
		 ((looking-at "\\<when\\>\\|\\<otherwise\\>")
		  (setq indent (+ indent
				  simula-substatement-offset
				  (if (memq temp '(?W ?w))
				      (car simula-if-indent)
				    (cdr simula-if-indent))))
		  (simula-find-inspect)))
		;; found the start of a [sub]statement
		;; add indentation for continued statement
		(if continued
		    (setq indent
			  (+ indent
			     (if (listp simula-continued-statement-offset)
				 (car simula-continued-statement-offset)
			       simula-continued-statement-offset))))
		(setq start-line
		      (line-beginning-position)
		      continued nil))
	    ;; search failed .. point is at beginning of line
	    ;; determine if we should continue searching
	    ;; (at or before comment or label)
	    ;; temp = t means finished
	    (setq temp
		  (and (not (simula-context))
		       (save-excursion
			 (skip-chars-forward " \t\f")
			 (or (looking-at "virtual")
			     (not
			      (looking-at
			       "!\\|comment\\>\\|[a-z0-9_]*[ \t\f]*:[^-=]")))))
		  prev-cont continued)
	    ;; if we are finished, find current line's indentation
	    (if temp
		(setq indent (+ indent (current-indentation))))
	    ;; find next line with non-comment SIMULA text
	    ;; maybe indent extra if statement continues
	    (simula-skip-comment-backward)
	    (setq continued
		  (and (not (bobp))
		       (if (eq (char-syntax (preceding-char)) ?w)
			   (save-excursion
			     (backward-word-strictly 1)
			     (not (looking-at
				   "begin\\|then\\|else\\|when\\|otherwise\\|do")))
			 (not (memq (preceding-char) '(?: ?\;))))))
	    ;; if we the state of the continued-variable
	    ;; changed, add indentation for continued statement
	    (if (or (and prev-cont (not continued))
		    (and continued
			 (listp simula-continued-statement-offset)))
		(setq indent
		      (+ indent
			 (if (listp simula-continued-statement-offset)
			     (car simula-continued-statement-offset)
			   simula-continued-statement-offset))))
	    ;; while ends if point is at beginning of line at loop test
	    (if (not temp)
		(setq start-line (line-beginning-position))
	      (beginning-of-line))))
        ;;
	;; return indentation
	;;
	indent)))))


(defun simula-find-if ()
  "Find starting IF of a IF-THEN[-ELSE[-IF-THEN...]] statement."
  (catch 'simula-out
    (while t
      (if (and (simula-search-backward "\\<if\\>\\|;\\|\\<begin\\>"nil t)
	       (memq (following-char) '(?I ?i)))
	  (save-excursion
	    ;;
	    ;; find out if this IF was really the start of the IF statement
	    ;;
	    (simula-skip-comment-backward)
	    (if (and (eq (char-syntax (preceding-char)) ?w)
		     (progn
		       (backward-word-strictly 1)
		       (looking-at "else\\>")))
		()
	      (throw 'simula-out t)))
	(if (not (looking-at "\\<if\\>"))
	    (error "Missing IF or misplaced BEGIN or ';' (can't find IF)")
	  ;;
	  ;; we were at the starting IF in the first place..
	  ;;
	  (throw 'simula-out t))))))


(defun simula-find-inspect ()
  "Find INSPECT matching WHEN or OTHERWISE."
  (catch 'simula-out
    (let ((level 0))
      ;;
      ;; INSPECTs can be nested, have to find the corresponding one
      ;;
      (while t
	(if (and (simula-search-backward "\\<inspect\\>\\|\\<otherwise\\>\\|;"
					  nil t)
		 (/= (following-char) ?\;))
	    (if (memq (following-char) '(?O ?o))
		(setq level (1+ level))
	      (if (zerop level)
		  (throw 'simula-out t)
		(setq level (1- level))))
	  (error "Missing INSPECT or misplaced ';' (can't find INSPECT)"))))))


(defun simula-find-do-match ()
  "Find keyword matching DO: FOR, WHILE, INSPECT or WHEN."
  (while (and (re-search-backward
	       "\\<\\(do\\|for\\|while\\|inspect\\|when\\|end\\|begin\\)\\>\\|;"
	       nil 'move)
	      (simula-context)))
  (if (and (looking-at "\\<\\(for\\|while\\|inspect\\|when\\)\\>")
	   (not (simula-context)))
      () ;; found match
    (error "No matching FOR, WHILE or INSPECT for DO, or misplaced ';'")))


(defun simula-inside-parens ()
  "Return position after `(' on line if inside parentheses, nil otherwise."
  (save-excursion
    (let ((parlevel 0))
      (catch 'simula-out
	(while t
	  (if (re-search-backward "(\\|)\\|;" nil t)
	      (if (eq (simula-context) nil)
		  ;; found something - check it out
		  (cond
		   ((eq (following-char) ?\;)
		    (if (zerop parlevel)
			(throw 'simula-out nil)
		      (error "Parenthesis mismatch or misplaced ';'")))
		   ((eq (following-char) ?\()
		    (if (zerop parlevel)
			(throw 'simula-out (1+ (current-column)))
		      (setq parlevel (1- parlevel))))
		   (t (setq parlevel (1+ parlevel))))
		);; nothing - inside comment or string
	    ;; search failed
	    (throw 'simula-out nil)))))))


(defun simula-goto-definition ()
  "Goto point of definition of variable, procedure or class."
  (interactive))


(defun simula-expand-stdproc ()
  (if (or (not simula-abbrev-stdproc) (simula-context))
      (unexpand-abbrev)
    (cond
     ((eq simula-abbrev-stdproc 'upcase) (upcase-word -1))
     ((eq simula-abbrev-stdproc 'downcase) (downcase-word -1))
     ((eq simula-abbrev-stdproc 'capitalize) (capitalize-word -1))
     ((eq simula-abbrev-stdproc 'abbrev-table)
      ;; If not in lowercase, expansions are always capitalized.
      ;; We then want to replace with the exact expansion.
      (if (equal (symbol-name last-abbrev) last-abbrev-text)
	  ()
	(downcase-word -1)
	(expand-abbrev))))))


(defun simula-expand-keyword ()
  (if (or (not simula-abbrev-keyword) (simula-context))
      (unexpand-abbrev)
    (cond
     ((eq simula-abbrev-keyword 'upcase) (upcase-word -1))
     ((eq simula-abbrev-keyword 'downcase) (downcase-word -1))
     ((eq simula-abbrev-keyword 'capitalize) (capitalize-word -1))
     ((eq simula-abbrev-stdproc 'abbrev-table)
      (if (equal (symbol-name last-abbrev) last-abbrev-text)
	  ()
	(downcase-word -1)
	(expand-abbrev))))))


(defun simula-electric-keyword ()
  "Expand SIMULA keyword.  If it starts the line, reindent."
  ;; redisplay
  (let ((show-char (eq this-command 'self-insert-command)))
    ;; If the abbrev expansion results in reindentation, the user may have
    ;; to wait some time before the character he typed is displayed
    ;; (the char causing the expansion is inserted AFTER the hook function
    ;; is called). This is annoying in case of normal characters.
    ;; However, if the user pressed a key bound to newline, it is better
    ;; to have the line inserted after the begin-end match.
    (if show-char
	(progn
	  (insert-char last-command-event 1)
	  (sit-for 0)
	  (backward-char 1)))
    (if (let ((where (simula-context))
	      (case-fold-search t))
	  (if where
	      (if (and (eq where 2) (eq (char-syntax (preceding-char)) ?w))
		  (save-excursion
		    (backward-word-strictly 1)
		    (not (looking-at "end\\>"))))))
	(unexpand-abbrev)
      (cond
       ((not simula-abbrev-keyword) (unexpand-abbrev))
       ((eq simula-abbrev-keyword 'upcase) (upcase-word -1))
       ((eq simula-abbrev-keyword 'downcase) (downcase-word -1))
       ((eq simula-abbrev-keyword 'capitalize) (capitalize-word -1)))
      (let ((pos (- (point-max) (point)))
	    (case-fold-search t))
	(condition-case nil
	    (progn
	      ;; check if the expanded word is on the beginning of the line.
	      (if (and (eq (char-syntax (preceding-char)) ?w)
		       (progn
			 (backward-word-strictly 1)
			 (if (looking-at "end\\>")
			     (save-excursion
			       (simula-backward-up-level 1)
			       (if (pos-visible-in-window-p)
				   (sit-for 1)
				 (message "Matches %s"
					  (buffer-substring
					   (point)
					   (+ (point) (window-width)))))))
			 (skip-chars-backward " \t\f")
			 (bolp)))
		  (let ((indent (simula-calculate-indent)))
		    (if (eq indent (current-indentation))
			()
		      (delete-horizontal-space)
		      (indent-to indent)))
		(skip-chars-forward " \t\f"))
	      ;; check for END - blow whistles and ring bells

	      (goto-char (- (point-max) pos))
	      (if show-char
		  (delete-char 1)))
	  (quit (goto-char (- (point-max) pos))))))))


(defun simula-search-backward (regexp &optional bound noerror)
  "Search backward from point for regular expression REGEXP,
ignoring matches found inside SIMULA comments, string literals,
and BEGIN..END blocks.
Set point to the end of the occurrence found, and return point.
An optional second argument BOUND bounds the search, it is a buffer position.
The match found must not extend after that position.  Optional third argument
NOERROR, if t, means if fail just return nil (no error).
If not nil and not t, move to limit of search and return nil."
  (let ((comb-regexp (concat regexp "\\|\\<end\\>"))
        (start-point (point))
        context match)
    (catch 'simula-backward
      (while (re-search-backward comb-regexp bound 1)
	;; We have a match, check SIMULA context at match-beginning
	;; to see if we are outside comments etc.
	;; Set MATCH to t if we found a true match,
	;; set MATCH to 'BLOCK if we found a BEGIN..END block,
	;; else set MATCH to nil.
	(save-match-data
	  (setq context (simula-context))
	  (cond
	   ((eq context nil)
	    (setq match (if (looking-at regexp) t 'BLOCK)))
	   ;; A comment-ending `;' is part of the comment, and shouldn't match.
	   ;; ((eq context 0)
	   ;;  (setq match (if (eq (following-char) ?\;) t nil)))
	   ((eq context 2)
	    (setq match (if (and (looking-at regexp)
				 (looking-at ";\\|\\<end\\>\\|\\<else\\>\\|\\<otherwise\\>\\|\\<when\\>"))
			    t
			  (if (looking-at "\\<end\\>") 'BLOCK nil))))
	   (t (setq match nil))))
	;; Exit if true match
	(if (eq match t) (throw 'simula-backward (point)))
	(if (eq match 'BLOCK)
	;; We found the END of a block
	    (let ((level 0))
	      (while (natnump level)
		  (if (re-search-backward "\\<begin\\>\\|\\<end\\>" bound 1)
		      (let ((context (simula-context)))
			;;    We found a BEGIN -> decrease level count
			(cond ((and (eq context nil)
				   (memq (following-char) '(?b ?B)))
			       (setq level (1- level)))
			      ;; END -> increase level count
			      ((and (memq context '(nil 2))
				    (memq (following-char) '(?e ?E)))
			       (setq level (1+ level)))))
		    ;; Block search failed.  Action depends on noerror.
		    (if (or (not noerror) (eq noerror t))
			(goto-char start-point))
		    (if (not noerror)
			(signal 'search-failed (list regexp)))
		    (throw 'simula-backward nil))))))
      ;; Search failed.  Action depends on noerror.
      (if (or (not noerror) (eq noerror t))
	  (goto-char start-point))
      (if noerror
	  nil
	(signal 'search-failed (list regexp))))))


(defun simula-search-forward (regexp &optional bound noerror)
  "Search forward from point for regular expression REGEXP,
ignoring matches found inside SIMULA comments, string literals,
and BEGIN..END blocks.
Set point to the end of the occurrence found, and return point.
An optional second argument BOUND bounds the search, it is a buffer position.
The match found must not extend after that position.  Optional third argument
NOERROR, if t, means if fail just return nil (no error).
If not nil and not t, move to limit of search and return nil."
  (let ((comb-regexp (concat regexp "\\|\\<begin\\>"))
        (start-point (point))
	context match)
    (catch 'simula-forward
      (while (re-search-forward comb-regexp bound 1)
	;; We have a match, check SIMULA context at match-beginning
	;; to see if we are outside comments.
	;; Set MATCH to t if we found a true match,
	;; set MATCH to 'BLOCK if we found a BEGIN..END block,
	;; else set MATCH to nil.
	(save-match-data
	  (save-excursion
	    (goto-char (match-beginning 0))
	    (setq context (simula-context))
	    (cond
	     ((not context)
	      (setq match (if (looking-at regexp) t 'BLOCK)))
	     ;; Comment-ending `;' is part of the comment, and shouldn't match.
	     ;; ((eq context 0)
	     ;;  (setq match (if (eq (following-char) ?\;) t nil)))
	     ((eq context 2)
	      (setq match (if (and (looking-at regexp)
				   (looking-at ";\\|\\<end\\>\\|\\<else\\>\\|\\<otherwise\\>\\|\\<when\\>")) t nil)))
	     (t (setq match nil)))))
	;; Exit if true match
	(if (eq match t) (throw 'simula-forward (point)))
	(if (eq match 'BLOCK)
	;; We found the BEGINning of a block
	    (let ((level 0))
	      (while (natnump level)
		  (if (re-search-forward "\\<begin\\>\\|\\<end\\>" bound 1)
		      (let ((context (simula-context)))
			;;    We found a BEGIN -> increase level count
			(cond ((eq context nil) (setq level (1+ level)))
			      ;; END -> decrease level count
			      ((and (eq context 2)
				    ;; Don't match BEGIN inside END comment
				    (memq (preceding-char) '(?d ?D)))
			       (setq level (1- level)))))
		    ;; Block search failed.  Action depends on noerror.
		    (if (or (not noerror) (eq noerror t))
			(goto-char start-point))
		    (if (not noerror)
			(signal 'search-failed (list regexp)))
		    (throw 'simula-forward nil))))))
      ;; Search failed.  Action depends on noerror.
      (if (or (not noerror) (eq noerror t))
	  (goto-char start-point))
      (if noerror
	  nil
	(signal 'search-failed (list regexp))))))


(defun simula-install-standard-abbrevs ()
  "Define Simula keywords, procedures and classes in local abbrev table."
  ;; procedure and class names are as of the SIMULA 87 standard.
  (interactive)
  (dolist (args
	  '(("abs" "Abs" simula-expand-stdproc)
	    ("accum" "Accum" simula-expand-stdproc)
	    ("activate" "ACTIVATE" simula-expand-keyword)
	    ("addepsilon" "AddEpsilon" simula-expand-stdproc)
	    ("after" "AFTER" simula-expand-keyword)
	    ("and" "AND" simula-expand-keyword)
	    ("arccos" "ArcCos" simula-expand-stdproc)
	    ("arcsin" "ArcSin" simula-expand-stdproc)
	    ("arctan" "ArcTan" simula-expand-stdproc)
	    ("arctan2" "ArcTan2" simula-expand-stdproc)
	    ("array" "ARRAY" simula-expand-keyword)
	    ("at" "AT" simula-expand-keyword)
	    ("before" "BEFORE" simula-expand-keyword)
	    ("begin" "BEGIN" simula-expand-keyword)
	    ("blanks" "Blanks" simula-expand-stdproc)
	    ("boolean" "BOOLEAN" simula-expand-keyword)
	    ("breakoutimage" "BreakOutImage" simula-expand-stdproc)
	    ("bytefile" "ByteFile" simula-expand-stdproc)
	    ("call" "Call" simula-expand-stdproc)
	    ("cancel" "Cancel" simula-expand-stdproc)
	    ("cardinal" "Cardinal" simula-expand-stdproc)
	    ("char" "Char" simula-expand-stdproc)
	    ("character" "CHARACTER" simula-expand-keyword)
	    ("checkpoint" "CheckPoint" simula-expand-stdproc)
	    ("class" "CLASS" simula-expand-keyword)
	    ("clear" "Clear" simula-expand-stdproc)
	    ("clocktime" "ClockTime" simula-expand-stdproc)
	    ("close" "Close" simula-expand-stdproc)
	    ("comment" "COMMENT" simula-expand-keyword)
	    ("constant" "Constant" simula-expand-stdproc)
	    ("copy" "Copy" simula-expand-stdproc)
	    ("cos" "Cos" simula-expand-stdproc)
	    ("cosh" "CosH" simula-expand-stdproc)
	    ("cotan" "CoTan" simula-expand-stdproc)
	    ("cputime" "CpuTime" simula-expand-stdproc)
	    ("current" "Current" simula-expand-stdproc)
	    ("datetime" "DateTime" simula-expand-stdproc)
	    ("decimalmark" "DecimalMark" simula-expand-stdproc)
	    ("delay" "DELAY" simula-expand-keyword)
	    ("deleteimage" "DeleteImage" simula-expand-stdproc)
	    ("detach" "Detach" simula-expand-stdproc)
	    ("digit" "Digit" simula-expand-stdproc)
	    ("directbytefile" "DirectByteFile" simula-expand-stdproc)
	    ("directfile" "DirectFile" simula-expand-stdproc)
	    ("discrete" "Discrete" simula-expand-stdproc)
	    ("do" "DO" simula-expand-keyword)
	    ("downcase" "Downcase" simula-expand-stdproc)
	    ("draw" "Draw" simula-expand-stdproc)
	    ("eject" "Eject" simula-expand-stdproc)
	    ("else" "ELSE" simula-electric-keyword)
	    ("empty" "Empty" simula-expand-stdproc)
	    ("end" "END" simula-electric-keyword)
	    ("endfile" "Endfile" simula-expand-stdproc)
	    ("entier" "Entier" simula-expand-stdproc)
	    ("eq" "EQ" simula-expand-keyword)
	    ("eqv" "EQV" simula-expand-keyword)
	    ("erlang" "Erlang" simula-expand-stdproc)
	    ("error" "Error" simula-expand-stdproc)
	    ("evtime" "EvTime" simula-expand-stdproc)
	    ("exp" "Exp" simula-expand-stdproc)
	    ("external" "EXTERNAL" simula-expand-keyword)
	    ("false" "FALSE" simula-expand-keyword)
	    ("field" "Field" simula-expand-stdproc)
	    ("file" "File" simula-expand-stdproc)
	    ("first" "First" simula-expand-stdproc)
	    ("follow" "Follow" simula-expand-stdproc)
	    ("for" "FOR" simula-expand-keyword)
	    ("ge" "GE" simula-expand-keyword)
	    ("getchar" "GetChar" simula-expand-stdproc)
	    ("getfrac" "GetFrac" simula-expand-stdproc)
	    ("getint" "GetInt" simula-expand-stdproc)
	    ("getreal" "GetReal" simula-expand-stdproc)
	    ("go" "GO" simula-expand-keyword)
	    ("goto" "GOTO" simula-expand-keyword)
	    ("gt" "GT" simula-expand-keyword)
	    ("head" "Head" simula-expand-stdproc)
	    ("hidden" "HIDDEN" simula-expand-keyword)
	    ("histd" "HistD" simula-expand-stdproc)
	    ("histo" "Histo" simula-expand-stdproc)
	    ("hold" "Hold" simula-expand-stdproc)
	    ("idle" "Idle" simula-expand-stdproc)
	    ("if" "IF" simula-expand-keyword)
	    ("image" "Image" simula-expand-stdproc)
	    ("imagefile" "ImageFile" simula-expand-stdproc)
	    ("imp" "IMP" simula-expand-keyword)
	    ("in" "IN" simula-expand-keyword)
	    ("inbyte" "InByte" simula-expand-stdproc)
	    ("inbytefile" "InByteFile" simula-expand-stdproc)
	    ("inchar" "InChar" simula-expand-stdproc)
	    ("infile" "InFile" simula-expand-stdproc)
	    ("infrac" "InFrac" simula-expand-stdproc)
	    ("inimage" "InImage" simula-expand-stdproc)
	    ("inint" "InInt" simula-expand-stdproc)
	    ("inner" "INNER" simula-expand-keyword)
	    ("inreal" "InReal" simula-expand-stdproc)
	    ("inrecord" "InRecord" simula-expand-stdproc)
	    ("inspect" "INSPECT" simula-expand-keyword)
	    ("integer" "INTEGER" simula-expand-keyword)
	    ("intext" "InText" simula-expand-stdproc)
	    ("into" "Into" simula-expand-stdproc)
	    ("is" "IS" simula-expand-keyword)
	    ("isochar" "ISOChar" simula-expand-stdproc)
	    ("isopen" "IsOpen" simula-expand-stdproc)
	    ("isorank" "ISORank" simula-expand-stdproc)
	    ("label" "LABEL" simula-expand-keyword)
	    ("last" "Last" simula-expand-stdproc)
	    ("lastitem" "LastItem" simula-expand-stdproc)
	    ("lastloc" "LastLoc" simula-expand-stdproc)
	    ("le" "LE" simula-expand-keyword)
	    ("length" "Length" simula-expand-stdproc)
	    ("letter" "Letter" simula-expand-stdproc)
	    ("line" "Line" simula-expand-stdproc)
	    ("linear" "Linear" simula-expand-stdproc)
	    ("linesperpage" "LinesPerPage" simula-expand-stdproc)
	    ("link" "Link" simula-expand-stdproc)
	    ("linkage" "Linkage" simula-expand-stdproc)
	    ("ln" "Ln" simula-expand-stdproc)
	    ("locate" "Locate" simula-expand-stdproc)
	    ("location" "Location" simula-expand-stdproc)
	    ("lock" "Lock" simula-expand-stdproc)
	    ("locked" "Locked" simula-expand-stdproc)
	    ("log10" "Log10" simula-expand-stdproc)
	    ("long" "LONG" simula-expand-keyword)
	    ("lowcase" "LowCase" simula-expand-stdproc)
	    ("lowerbound" "LowerBound" simula-expand-stdproc)
	    ("lowten" "LowTen" simula-expand-stdproc)
	    ("lt" "LT" simula-expand-keyword)
	    ("main" "Main" simula-expand-stdproc)
	    ("max" "Max" simula-expand-stdproc)
	    ("maxint" "MaxInt" simula-expand-stdproc)
	    ("maxlongreal" "MaxLongReal" simula-expand-stdproc)
	    ("maxloc" "MaxLoc" simula-expand-stdproc)
	    ("maxrank" "MaxRank" simula-expand-stdproc)
	    ("maxreal" "MaxReal" simula-expand-stdproc)
	    ("min" "Min" simula-expand-stdproc)
	    ("minint" "MinInt" simula-expand-stdproc)
	    ("minlongreal" "MinLongReal" simula-expand-stdproc)
	    ("minrank" "MinRank" simula-expand-stdproc)
	    ("minreal" "MinReal" simula-expand-stdproc)
	    ("mod" "Mod" simula-expand-stdproc)
	    ("more" "More" simula-expand-stdproc)
	    ("name" "NAME" simula-expand-keyword)
	    ("ne" "NE" simula-expand-keyword)
	    ("negexp" "NegExp" simula-expand-stdproc)
	    ("new" "NEW" simula-expand-keyword)
	    ("nextev" "NextEv" simula-expand-stdproc)
	    ("none" "NONE" simula-expand-keyword)
	    ("normal" "Normal" simula-expand-stdproc)
	    ("not" "NOT" simula-expand-keyword)
	    ("notext" "NOTEXT" simula-expand-keyword)
	    ("open" "Open" simula-expand-stdproc)
	    ("or" "OR" simula-expand-keyword)
	    ("otherwise" "OTHERWISE" simula-electric-keyword)
	    ("out" "Out" simula-expand-stdproc)
	    ("outbyte" "OutByte" simula-expand-stdproc)
	    ("outbytefile" "OutByteFile" simula-expand-stdproc)
	    ("outchar" "OutChar" simula-expand-stdproc)
	    ("outfile" "OutFile" simula-expand-stdproc)
	    ("outfix" "OutFix" simula-expand-stdproc)
	    ("outfrac" "OutFrac" simula-expand-stdproc)
	    ("outimage" "OutImage" simula-expand-stdproc)
	    ("outint" "OutInt" simula-expand-stdproc)
	    ("outreal" "OutReal" simula-expand-stdproc)
	    ("outrecord" "OutRecord" simula-expand-stdproc)
	    ("outtext" "OutText" simula-expand-stdproc)
	    ("page" "Page" simula-expand-stdproc)
	    ("passivate" "Passivate" simula-expand-stdproc)
	    ("poisson" "Poisson" simula-expand-stdproc)
	    ("pos" "Pos" simula-expand-stdproc)
	    ("precede" "Precede" simula-expand-stdproc)
	    ("pred" "Pred" simula-expand-stdproc)
	    ("prev" "Prev" simula-expand-stdproc)
	    ("printfile" "PrintFile" simula-expand-stdproc)
	    ("prior" "PRIOR" simula-expand-keyword)
	    ("procedure" "PROCEDURE" simula-expand-keyword)
	    ("process" "Process" simula-expand-stdproc)
	    ("protected" "PROTECTED" simula-expand-keyword)
	    ("putchar" "PutChar" simula-expand-stdproc)
	    ("putfix" "PutFix" simula-expand-stdproc)
	    ("putfrac" "PutFrac" simula-expand-stdproc)
	    ("putint" "PutInt" simula-expand-stdproc)
	    ("putreal" "PutReal" simula-expand-stdproc)
	    ("qua" "QUA" simula-expand-keyword)
	    ("randint" "RandInt" simula-expand-stdproc)
	    ("rank" "Rank" simula-expand-stdproc)
	    ("reactivate" "REACTIVATE" simula-expand-keyword)
	    ("real" "REAL" simula-expand-keyword)
	    ("ref" "REF" simula-expand-keyword)
	    ("resume" "Resume" simula-expand-stdproc)
	    ("setaccess" "SetAccess" simula-expand-stdproc)
	    ("setpos" "SetPos" simula-expand-stdproc)
	    ("short" "SHORT" simula-expand-keyword)
	    ("sign" "Sign" simula-expand-stdproc)
	    ("simset" "SimSet" simula-expand-stdproc)
	    ("simulaid" "SimulaId" simula-expand-stdproc)
	    ("simulation" "Simulation" simula-expand-stdproc)
	    ("sin" "Sin" simula-expand-stdproc)
	    ("sinh" "SinH" simula-expand-stdproc)
	    ("sourceline" "SourceLine" simula-expand-stdproc)
	    ("spacing" "Spacing" simula-expand-stdproc)
	    ("sqrt" "Sqrt" simula-expand-stdproc)
	    ("start" "Start" simula-expand-stdproc)
	    ("step" "STEP" simula-expand-keyword)
	    ("strip" "Strip" simula-expand-stdproc)
	    ("sub" "Sub" simula-expand-stdproc)
	    ("subepsilon" "SubEpsilon" simula-expand-stdproc)
	    ("suc" "Suc" simula-expand-stdproc)
	    ("switch" "SWITCH" simula-expand-keyword)
	    ("sysin" "SysIn" simula-expand-stdproc)
	    ("sysout" "SysOut" simula-expand-stdproc)
	    ("tan" "Tan" simula-expand-stdproc)
	    ("tanh" "TanH" simula-expand-stdproc)
	    ("terminate_program" "Terminate_Program" simula-expand-stdproc)
	    ("terminated" "Terminated" simula-expand-stdproc)
	    ("text" "TEXT" simula-expand-keyword)
	    ("then" "THEN" simula-electric-keyword)
	    ("this" "THIS" simula-expand-keyword)
	    ("time" "Time" simula-expand-stdproc)
	    ("to" "TO" simula-expand-keyword)
	    ("true" "TRUE" simula-expand-keyword)
	    ("uniform" "Uniform" simula-expand-stdproc)
	    ("unlock" "Unlock" simula-expand-stdproc)
	    ("until" "UNTIL" simula-expand-keyword)
	    ("upcase" "Upcase" simula-expand-stdproc)
	    ("upperbound" "UpperBound" simula-expand-stdproc)
	    ("value" "VALUE" simula-expand-keyword)
	    ("virtual" "VIRTUAL" simula-expand-keyword)
	    ("wait" "Wait" simula-expand-stdproc)
	    ("when" "WHEN" simula-electric-keyword)
	    ("while" "WHILE" simula-expand-keyword)))
    (define-abbrev simula-mode-abbrev-table
      (nth 0 args) (nth 1 args) (nth 2 args) nil 'system)))

(if simula-abbrev-file
    (read-abbrev-file simula-abbrev-file))
(let (abbrevs-changed)
  (simula-install-standard-abbrevs))

;; Hilit mode support.
(when (fboundp 'hilit-set-mode-patterns)
  (when (and (boundp 'hilit-patterns-alist)
	     (not (assoc 'simula-mode hilit-patterns-alist)))
    (hilit-set-mode-patterns
     'simula-mode
     '(
       ("^%\\([ \t\f].*\\)?$" nil comment)
       ("^%include\\>" nil include)
       ("\"[^\"\n]*\"\\|'.'\\|'![0-9]+!'" nil string)
       ("\\<\\(ACTIVATE\\|AFTER\\|AND\\|ARRAY\\|AT\\|BEFORE\\|BEGIN\\|BOOLEAN\\|CHARACTER\\|CLASS\\|DELAY\\|DO\\|ELSE\\|END\\|EQ\\|EQV\\|EXTERNAL\\|FALSE\\|FOR\\|GE\\|GO\\|GOTO\\|GT\\|HIDDEN\\|IF\\|IMP\\|IN\\|INNER\\|INSPECT\\|INTEGER\\|IS\\|LABEL\\|LE\\|LONG\\|LT\\|NAME\\|NE\\|NEW\\|NONE\\|NOT\\|NOTEXT\\|OR\\|OTHERWISE\\|PRIOR\\|PROCEDURE\\|PROTECTED\\|QUA\\|REACTIVATE\\|REAL\\|REF\\|SHORT\\|STEP\\|SWITCH\\|TEXT\\|THEN\\|THIS\\|TO\\|TRUE\\|UNTIL\\|VALUE\\|VIRTUAL\\|WHEN\\|WHILE\\)\\>" nil keyword)
       ("!\\|\\<COMMENT\\>" ";" comment))
     nil 'case-insensitive)))

;; defuns for submitting bug reports

(defconst simula-mode-help-address "bug-gnu-emacs@gnu.org"
  "Address accepting submission of `simula-mode' bug reports.")

(make-obsolete-variable 'simula-mode-help-address 'report-emacs-bug-address
			"24.4")

(define-obsolete-function-alias 'simula-submit-bug-report
  'report-emacs-bug "24.4")

(provide 'simula)

;;; simula.el ends here
