CR1 editing mode for CRBasic used in LoggerNet software from Campbell Scientific

crbasic-mode.el

;;; crbasic-mode.el --- CR1 editing mode

;; Copyright (C) 2014 Mikhail Titov

;; Author: Mikhail Titov <mlt@gmx.us>
;; URL: https://
;; Keywords: crbasic, cr1
;; Version: 1.0.0

;; 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/>.


;; Major mode for editing CR1 files with CRBasic for LoggerNet
;; software from Campbell Scientific.
;; 
;; It is heavily based on mode tutorial from Emacs
;; wiki. http://www.emacswiki.org/emacs/ModeTutorial

(defvar crbasic-mode-hook nil)

(defvar crbasic-mode-map
  (let ((map (make-keymap)))
    (define-key map "\C-j" 'newline-and-indent)
    map)
  "Keymap for crbasic major mode")

;;;###autoload
(add-to-list 'auto-mode-alist '("\\.cr1\\'" . crbasic-mode))

(defvar crbasic-font-lock-keywords
  (list
   '("'.*$" . font-lock-comment-face)
   '("\\<[#]\\(If\\|Else\\|EndIf\\)\\>" . font-lock-preprocessor-face)
   '("\\<\\(If\\|Then\\|Else\\|EndIf\\|For\\|To\\|\\(Next\\)?\\(Sub\\)?Scan\\|Next\\|\\(Begin\\|End\\)Prog\\|\\(Data\\|End\\)Table\\)\\>" . font-lock-builtin-face)
   '("\\<\\(Dim\\|Alias\\|As\\|Const\\|Public\\|Units\\|CallTable\\)\\>\\|[()<>=*]+" . font-lock-keyword-face)
   '("\\<\\(DataInterval\\|Minimum\\|Maximum\\|Average\\|Sample\\|Totalize\\|WindVector\\|PortSet\\|Delay\\|SerialFlush\\|Serial\\(In\\|Open\\)\\|SplitStr\\|Battery\\|PanelTemp\\|VoltDiff\\|PulseCount\\)\\>" . font-lock-function-name-face)
   '("\\<\\(IEEE4\\|mV[[:digit:]]+\\|Min\\|m?Sec\\|_60Hz\\|Com[[:digit:]]\\)\\>" . font-lock-constant-face)
   '("\\<Long\\>" . font-lock-type-face)
   ;; '("\\('\\w*'\\)" . font-lock-variable-name-face)
   )
  "Default highlighting expressions for CRBasic mode")

(defun crbasic-indent-line ()
  "Indent current line as CRBasic code"
  (interactive)
  (beginning-of-line)
  (if (bobp)  ; Check for rule 1
      (indent-line-to 0)
    (let ((not-indented t) cur-indent)
      (if (looking-at "^[ \t]*\\(End\\|NextScan\\|Next\\)") ; Check for rule 2
	  (progn
	    (save-excursion
	      (forward-line -1)
	      (setq cur-indent (- (current-indentation) tab-width)))
	    (if (< cur-indent 0)
		(setq cur-indent 0)))
        (save-excursion 
          (while not-indented
            (forward-line -1)
            (if (looking-at "^[ \t]*\\(End\\|Next\\(Sub\\)?Scan\\|Next\\)") ; Check for rule 3
                (progn
                  (setq cur-indent (current-indentation))
                  (setq not-indented nil))
              ; Check for rule 4
              (if (looking-at "^[ \t]*\\(BeginProg\\|If.+Then[ \t]*\\($\\|'\\)\\|For\\|DataTable\\)")
                  (progn
                    (setq cur-indent (+ (current-indentation) tab-width))
                    (setq not-indented nil))
                (if (bobp) ; Check for rule 5
                    (setq not-indented nil)))))))
      (if cur-indent
          (indent-line-to cur-indent)
        (indent-line-to 0))))) ; If we didn't see an indentation hint, then allow no indentation

(defvar crbasic-mode-syntax-table
  (let ((st (make-syntax-table)))
    (modify-syntax-entry ?' "< b" st)
    (modify-syntax-entry ?\n "> b" st)
    (modify-syntax-entry ?_ "w" st)
    st)
  "Syntax table for crbasic-mode")

(define-derived-mode crbasic-mode fundamental-mode "CRBasic"
  "Major mode for editing CRBasic files."
  (setq tab-width 2)
  (setq comment-start "'")
  (set (make-local-variable 'font-lock-defaults) '(crbasic-font-lock-keywords))
  (set (make-local-variable 'indent-line-function) 'crbasic-indent-line))

(provide 'crbasic-mode)