;;; dap16-mode.el --- mode for editing DAP-16 assembler code

;;; Commentary:

;; This mode was written by Philipp Hachtmann <hachti@hachti.de>.
;; It is based on the asm mode by Eric S. Raymond <esr@snark.thyrsus.com>

;; This minor mode is based on text mode.  It defines a private abbrev table
;; that can be used to save abbrevs for assembler mnemonics.  It binds just
;; five keys:
;;
;;	TAB		tab to next tab stop
;;	:		outdent preceding label, tab to tab stop
;;	comment char	place or move comment
;;			dap16-comment-char specifies which character this is;
;;			you can use a different character in different
;;			Asm mode buffers.
;;	C-j, C-m	newline and tab to tab stop
;;
;; Code is indented to the first tab stop level.

;; This mode runs two hooks:
;;   1) An dap16-mode-set-comment-hook before the part of the initialization
;; depending on dap16-comment-char, and
;;   2) an dap16-mode-hook at the end of initialization.

;;; Code:

(defgroup dap16 nil
  "DAP-16 Assembler programming"
  :group 'languages)

(defcustom dap16-comment-char ?*
  "*The comment-start character assumed by Asm mode."
  :type 'sexp
  :group 'asm)

;; XEmacs change (This is the primary difference, why was this
;;  feature removed? -sb)
(defcustom dap16-support-c-comments-p nil
  "*Support C style comments.  If t C style comments will be
supported.  This is mainly for the benefit of font-lock."
  :type 'boolean
  :group 'asm)

(defcustom dap16-mode-syntax-table nil
  "Syntax table used while in Asm mode.")

(defvar dap16-mode-abbrev-table nil
  "Abbrev table used while in Asm mode.")
(define-abbrev-table 'dap16-mode-abbrev-table ())

(defvar dap16-mode-map nil
  "Keymap for Asm mode.")

;;(if dap16-mode-map
;;    nil
  ;; XEmacs change
  (setq dap16-mode-map (make-sparse-keymap 'dap16-mode-map))
  ;; Note that the comment character isn't set up until dap16-mode is called.
  (define-key dap16-mode-map ":"	'dap16-colon)
  (define-key dap16-mode-map "\C-h"       'dap16-backspace)
  (define-key dap16-mode-map "\C-l"       'dap16-halfdelim)
  (define-key dap16-mode-map "\M-l"       'dap16-fulldelim)
  (define-key dap16-mode-map "\C-i"       'dap16-tabulator)
  (define-key dap16-mode-map "\C-cc"	'dap16-comment-region)
  (define-key dap16-mode-map "\C-c\C-c"	'dap16-comment-region)
  (define-key dap16-mode-map "\C-a"       'beginning-of-line)
  (define-key dap16-mode-map "\C-j"	'dap16-newline)
  (define-key dap16-mode-map "\C-m"	'dap16-newline)
;;  )

;;(defconst dap16-font-lock-keywords
;; '(("^\\(\\(\\sw\\|\\s_\\)+\\)\\>:?[ \t]*\\(\\sw+\\)?"
;;    (1 font-lock-function-name-face) (3 font-lock-keyword-face nil t))
;;   ("^\\s +\\(\\(\\sw\\|\\s_\\)+\\)" 1 font-lock-keyword-face))

;; "Additional expressions to highlight in Assembler mode.")

;; XEmacs change
;;(put 'dap16-mode 'font-lock-defaults '(dap16-font-lock-keywords))

;;(defvar dap16-code-level-empty-comment-pattern nil)
;;(defvar dap16-flush-left-empty-comment-pattern nil)
;;(defvar dap16-inline-empty-comment-pattern nil)

;;;###autoload
(defun dap16-mode ()
  "Major mode for editing Honeywell DAP-16 assembler code.
Features a private abbrev table and the following bindings:

\\[dap16-colon]\toutdent a preceding label, tab to next tab stop.
\\[tab-to-tab-stop]\ttab to next tab stop.
\\[dap16-newline]\tnewline, then tab to next tab stop.
\\[dap16-comment]\tsmart placement of assembler comments.

Turning on Asm mode runs the hook `dap16-mode-hook' at the end of initialization.

Special commands:
\\{dap16-mode-map}
"
  (interactive)

  (kill-all-local-variables)
  
  ;; The space after a comment char at the beginning of a line
  (make-local-variable 'dap16-comment-space)
  (setq dap16-comment-space " ")

  (setq mode-name "DAP-16")
  (setq major-mode 'dap16-mode)
  (setq local-abbrev-table dap16-mode-abbrev-table)
  
;;  (make-local-variable 'tab-stop-list)
;;  (setq tab-stop-list '(6 12 30))

;;(defconst dap16-font-lock-keywords
;; '(("^\\(\\(\\sw\\|\\s_\\)+\\)\\>:?[ \t]*\\(\\sw+\\)?"
;;    (1 font-lock-function-name-face) (3 font-lock-keyword-face nil t))
;;   ("^\\s +\\(\\(\\sw\\|\\s_\\)+\\)" 1 font-lock-keyword-face))

;; "Additional expressions to highlight in Assembler mode.")

 
  (setq dap16-font-lock-keywords
	'(
	  (dap16-comment-matcher . font-lock-comment-face)
;;	  ("\\<[0-9]+H[^ \t\n]*\\>" . font-lock-keyword-face)
	  
	  ("^\\(\\(\\sw\\|\\s_\\)+\\)\\>:?[ \t]*\\(\\sw+\\)?"
	  (1 font-lock-function-name-face) (3 font-lock-keyword-face nil t))
	  ("^\\s +\\(\\(\\sw\\|\\s_\\)+\\)" (1 font-lock-keyword-face))
)
	
	
   )


  (make-local-variable 'dap16-mode-syntax-table)
  (setq dap16-mode-syntax-table (make-syntax-table))
 
  (set-syntax-table dap16-mode-syntax-table)

  (make-local-variable 'font-lock-defaults)
  
  (setq font-lock-defaults '( 
	dap16-font-lock-keywords
	nil
	nil
	)
  )

  

  (run-hooks 'dap16-mode-set-comment-hook)
  ;; Make our own local child of dap16-mode-map
  ;; so we can define our own comment character.

  ;; XEmacs change
  (let ((ourmap (make-sparse-keymap)))
    (set-keymap-parents ourmap (list dap16-mode-map))
    (use-local-map ourmap))
  (local-set-key (vector dap16-comment-char) 'dap16-comment)
  ;; XEmacs change

;;  (modify-syntax-entry dap16-comment-char "<" dap16-mode-syntax-table)
;;  (modify-syntax-entry ?\n ">" dap16-mode-syntax-table)

;;  (modify-syntax-entry ?a "w" dap16-mode-syntax-table)


;;  (let ((cs (regexp-quote (char-to-string dap16-comment-char))))
;;    (make-local-variable 'comment-start)
;;    (setq comment-start (concat cs dap16-comment-space))
;;    (make-local-variable 'comment-start-skip)
;;    (setq comment-start-skip (concat cs "+[ \t]*"))
;;    (setq dap16-inline-empty-comment-pattern (concat "^.+" cs "+ *$"))
;;    (setq dap16-code-level-empty-comment-pattern (concat "^[\t ]+" cs cs " *$"))
;;    (setq dap16-flush-left-empty-comment-pattern (concat "^" cs cs cs " *$"))
;;    )
;;  (make-local-variable 'comment-end)
;;  (setq comment-end "")
  (make-local-variable 'comment-column)
  (setq comment-column 32)
;;  (setq fill-prefix "\t")
  (run-hooks 'dap16-mode-hook))

(defun dap16-colon ()
  "Insert a colon; if it follows a label, delete the label's indentation."
  (interactive)
  (cond
   ( (and (is-comment-line) (= (current-column) (length '(dap16-comment-char dap16-comment-space))))
     (dap16-comment-line)
     (tab-to-tab-stop)
     )

   ( (and (not (is-comment-line)) (save-excursion (beginning-of-line) (looking-at "[ \t]+\\(\\sw\\|\\s_\\)+$")))
     (save-excursion (beginning-of-line) (delete-horizontal-space))
     (tab-to-tab-stop)
     )
   
   (t 
    (insert ":")
    )
   )
  )


;_____________________________________________________________________________________________

(defun col ()
  (+ 1 (current-column))
)

(defun fc-pos()
  (save-excursion 
    (end-of-line)
    (setq cstart (col))
    (while (> (col) 16)
      (if (or (= (following-char) ?  ) (= (following-char) ?\t) (= (following-char) ?\n))
	  (setq cstart (col)))
      (backward-char 1))
      )
  cstart
)

(defun dap16-comment-matcher (limit)
;;(setq p1 (point))
;;(setq p2 (+ 2 (point)))

  (setq success nil) 
  (setq end-of-buffer-exit nil)
  
  ;; Consume Newline characters if present.
  (while (and (< (point) limit) (= (following-char) ?\n) ) (forward-char))
  
  ;; Save first location to highlight
  (setq p1 (point))
  (while  (and (< (point) limit) (not (and (= (following-char) ?\n) success)) (not end-of-buffer-exit))
    (if  (or (> (col) (fc-pos)) (is-comment-line))  
	(progn  (setq p2 (+ 1 (point))) 
		(if success nil (progn (setq success t) (setq p1 (- (point) 0))))))
    
    (forward-char))
  
  (if success (set-match-data (list (- p1 0) (- p2 0))))
  success
)
           

;_____________________________________________________________________________________________

(defun dap16-line-matches (pattern &optional withcomment)
  (save-excursion
    (beginning-of-line)
    (looking-at pattern)))

(defun dap16-pop-comment-level ()
  ;; Delete an empty comment ending current line.  Then set up for a new one,
  ;; on the current line if it was all comment, otherwise above it
  (end-of-line)
  (delete-horizontal-space)
  (while (= (preceding-char) dap16-comment-char)
    (delete-backward-char 1))
  (delete-horizontal-space)
  (if (bolp)
      nil
    (beginning-of-line)
    (open-line 1))
  )


(defun dap16-comment ()
  "Convert an empty comment to a `larger' kind, or start a new one.
These are the known comment classes:

   1 -- comment to the right of the code (at the comment-column)
   2 -- comment on its own line, indented like code
   3 -- comment on its own line, beginning at the left-most column.

Suggested usage:  while writing your code, trigger dap16-comment
repeatedly until you are satisfied with the kind of comment."
  (interactive)
 
 (setq comment-start "")

  (cond

   ;; Blank line?  Then start comment.
   ((dap16-line-matches "^[ \t]*$")
    (delete-horizontal-space)
    (insert dap16-comment-char dap16-comment-space) 
    )

   ;; Nonblank line with no comment chars in it?
   ;; Then start a comment at the current comment column
   ((and (= (col) 1) (is-comment-line))
    (dap16-comment-line)
    )

   ;; Flush-left comment present?  Just insert character.
;;   ((dap16-line-matches dap16-flush-left-empty-comment-pattern)
;;    (insert dap16-comment-char))

   ;; Fresh comment line??
   ((dap16-line-matches (format "^%c%s$" dap16-comment-char dap16-comment-space))
    (end-of-line)
    (delete-backward-char (length dap16-comment-space))
    (insert dap16-comment-char dap16-comment-char)
    (end-of-line)
   )

   
   ;; Empty code-level comment already present?
   ;; Then start flush-left comment, on line above if this one is nonempty. 
;;   ((dap16-line-matches dap16-code-level-empty-comment-pattern)
;;    (dap16-pop-comment-level)
;;    (insert dap16-comment-char dap16-comment-char comment-start))

   ;; Empty comment ends line?
   ;; Then make code-level comment, on line above if this one is nonempty. 
;;   ((dap16-line-matches dap16-inline-empty-comment-pattern)
;;    (dap16-pop-comment-level)
;;    (tab-to-tab-stop)
;;    (insert dap16-comment-char comment-start))

   ;; If all else fails, insert character
   (t
    (insert dap16-comment-char))

   )

 )

;; ****************************************************************************


(defun pos-in-line ()
  (- (point) (save-excursion (beginning-of-line) (point))))


;; Muss verbessert werden!
(defun at-begin-of-line ()
;;  (interactive)
;;    (setq pos (point) )
;;(save-excursion  
;;  (beginning-of-line)
;;    (if (= pos (point)) t nil)
;;    )
;;)
  (interactive)
  (if (= 0 (current-column)) t nil))


(defun is-comment-line ()
  (if (dap16-line-matches (format "^%c" dap16-comment-char))
    t
    nil)
)

(defun in-comment-spacing ()
 (if (> (current-column) (length (format "%c%s" dap16-comment-char dap16-comment-space))) nil t)
)

(defun dap16-comment-line()
 (interactive)
 (if (is-comment-line) 
     (save-excursion 
       (beginning-of-line) 
       (delete-char 1)
       (if (looking-at "^ ")
	   (delete-char 1)
	 )
     )
     (save-excursion (beginning-of-line) (insert dap16-comment-char dap16-comment-space)) 
  )
)

(defun line-start()
  (save-excursion
    (beginning-of-line)
    (point)
    )
)


(defun line-end()
  (save-excursion
    (end-of-line)
    (point)
    )
)

(defun dap16-comment-region()
 (interactive)
 
 (if (not (region-active-p)) (dap16-comment-line)
   (save-excursion 
     (goto-char (region-end))
     (setq lastline (line-number))
     (goto-char (region-beginning))
     (while (< (line-number) lastline)
       (dap16-comment-line)
       (next-line 1)
       ))))
    
   
(defun dap16-backspace ()
  (interactive)
  (if (and (is-comment-line) (in-comment-spacing))
      (delete-region (max (- (line-start) 1) 1) (point))
     (delete-backward-char 1)
  )
;;delete-backward-char (length (format "%c%s" dap16-comment-char dap16-comment-space))) (tab-to-tab-stop))
;; (delete-backward-char 1)
  )

(defun dap16-fulldelim ()
  (interactive)
  (make-local-variable 'count)
  (setq count 0)
  (if (dap16-line-matches (format "^%c%s$" dap16-comment-char dap16-comment-space)) 
       (progn (setq count 1)
       (end-of-line)
       (delete-backward-char (length dap16-comment-space)))
  )
  
  (while (< count 80) 
    (insert dap16-comment-char) 
    (setq count ( 1+ count)))
)


(defun dap16-halfdelim ()
  (interactive)
  (make-local-variable 'count)
  (setq count 0)
  (if (dap16-line-matches (format "^%c%s$" dap16-comment-char dap16-comment-space)) 
       (progn (setq count 1)
       (end-of-line)
       (delete-backward-char (length dap16-comment-space)))
  )
  
  (while (< count 40) 
    (insert dap16-comment-char) 
    (setq count ( 1+ count)))

)


(defun dap16-tabulator ()
  (interactive)
  (if (is-comment-line)
      (progn
	(setq target (prog2 (insert "\t") (current-column) (delete-backward-char 1)  ))
	     (while (< (current-column) target) (insert " "))
        )
      
       (tab-to-tab-stop)
     )
)


(defun dap16-newline ()
  "Insert LFD + fill-prefix, to bring us back to code-indent level."
  (interactive)
  
  (if (is-comment-line)
      (progn
       (if (at-begin-of-line) (goto-char (+ (point) 1)))
       (insert "\n" dap16-comment-char dap16-comment-space))
    ;; Not comment line
    (if (eolp) 
	 (progn (delete-horizontal-space)
                (insert "\n")  
		(tab-to-tab-stop)
	  )
      (insert "\n")  
     ;; (tab-to-tab-stop)
     )
     )
)
  

;; XEmacs addition
;;;###autoload(add-to-list 'auto-mode-alist '("\\.[sS]\\'" . dap16-mode))
;;;###autoload(add-to-list 'auto-mode-alist '("\\.asm\\'" . dap16-mode))

;;; dap16-mode.el ends here