;;; factor.el --- Interacting with Factor within emacs
;;
;; Authors: Eduardo Cavazos <wayo.cavazos@gmail.com>
;;          Jose A Ortega Ruiz <jao@gnu.org>
;; Keywords: languages

;;; Commentary:

;;; Quick setup:

;; Add these lines to your .emacs file:
;;
;;   (load-file "/scratch/repos/Factor/misc/factor.el")
;;   (setq factor-binary "/scratch/repos/Factor/factor")
;;   (setq factor-image "/scratch/repos/Factor/factor.image")
;;
;; Of course, you'll have to edit the directory paths for your system
;; accordingly. Alternatively, put this file in your load-path and use
;;
;;   (require 'factor)
;;
;; instead of load-file.
;;
;; That's all you have to do to "install" factor.el on your
;; system. Whenever you edit a factor file, Emacs will know to switch
;; to Factor mode.
;;
;; For further customization options,
;;   M-x customize-group RET factor
;;
;; To start a Factor listener inside Emacs,
;;   M-x run-factor

;;; Requirements:

(require 'font-lock)
(require 'comint)

;;; Customization:

(defgroup factor nil
  "Factor mode"
  :group 'languages)

(defcustom factor-default-indent-width 4
  "Default indentantion width for factor-mode.

This value will be used for the local variable
`factor-indent-width' in new factor buffers. For existing code,
we first check if `factor-indent-width' is set explicitly in a
local variable section or line (e.g. '! -*- factor-indent-witdth: 2 -*-').
If that's not the case, `factor-mode' tries to infer its correct
value from the existing code in the buffer."
  :type 'integer
  :group 'factor)

(defcustom factor-binary "~/factor/factor"
  "Full path to the factor executable to use when starting a listener."
  :type '(file :must-match t)
  :group 'factor)

(defcustom factor-image "~/factor/factor.image"
  "Full path to the factor image to use when starting a listener."
  :type '(file :must-match t)
  :group 'factor)

(defcustom factor-display-compilation-output t
  "Display the REPL buffer before compiling files."
  :type 'boolean
  :group 'factor)

(defcustom factor-mode-hook nil
  "Hook run when entering Factor mode."
  :type 'hook
  :group 'factor)

(defgroup factor-faces nil
  "Faces used in Factor mode"
  :group 'factor
  :group 'faces)

(defsubst factor--face (face) `((t ,(face-attr-construct face))))

(defface factor-font-lock-parsing-word (factor--face font-lock-keyword-face)
  "Face for parsing words."
  :group 'factor-faces)

(defface factor-font-lock-comment (factor--face font-lock-comment-face)
  "Face for comments."
  :group 'factor-faces)

(defface factor-font-lock-string (factor--face font-lock-string-face)
  "Face for strings."
  :group 'factor-faces)

(defface factor-font-lock-stack-effect (factor--face font-lock-comment-face)
  "Face for stack effect specifications."
  :group 'factor-faces)

(defface factor-font-lock-word-definition (factor--face font-lock-function-name-face)
  "Face for word, generic or method being defined."
  :group 'factor-faces)

(defface factor-font-lock-symbol-definition (factor--face font-lock-variable-name-face)
  "Face for name of symbol being defined."
  :group 'factor-faces)

(defface factor-font-lock-vocabulary-name (factor--face font-lock-constant-face)
  "Face for names of vocabularies in USE or USING."
  :group 'factor-faces)

(defface factor-font-lock-type-definition (factor--face font-lock-type-face)
  "Face for type (tuple) names."
  :group 'factor-faces)

(defface factor-font-lock-parsing-word (factor--face font-lock-keyword-face)
  "Face for parsing words."
  :group 'factor-faces)


;;; Factor mode font lock:

(defconst factor--parsing-words
  '("{" "}" "^:" "^::" ";" "<<" "<PRIVATE" ">>"
    "BIN:" "BV{" "B{" "C:" "C-STRUCT:" "C-UNION:" "CHAR:" "CS{" "C{"
    "DEFER:" "ERROR:" "EXCLUDE:" "FORGET:"
    "GENERIC#" "GENERIC:" "HEX:" "HOOK:" "H{"
    "IN:" "INSTANCE:" "INTERSECTION:"
    "M:" "MACRO:" "MACRO::" "MAIN:" "MATH:" "METHOD:" "MIXIN:"
    "OCT:" "POSTPONE:" "PREDICATE:" "PRIMITIVE:" "PRIVATE>" "PROVIDE:"
    "REQUIRE:"  "REQUIRES:" "SINGLETON:" "SLOT:" "SYMBOL:" "SYMBOLS:"
    "TUPLE:" "T{" "t\\??" "TYPEDEF:"
    "UNION:" "USE:" "USING:" "V{" "VAR:" "VARS:" "W{"))

(defconst factor--regex-parsing-words-ext
  (regexp-opt '("B" "call-next-method" "delimiter" "f" "flushable" "foldable"
                "initial:" "inline" "parsing" "read-only" "recursive")
              'words))

(defsubst factor--regex-second-word (prefixes)
  (format "^%s +\\([^ \r\n]+\\)" (regexp-opt prefixes t)))

(defconst factor--regex-word-definition
  (factor--regex-second-word '(":" "::" "M:" "GENERIC:")))

(defconst factor--regex-type-definition
  (factor--regex-second-word '("TUPLE:")))

(defconst factor--regex-symbol-definition
  (factor--regex-second-word '("SYMBOL:")))

(defconst factor--regex-using-line "^USING: +\\([^;]*\\);")
(defconst factor--regex-use-line "^USE: +\\(.*\\)$")

(defconst factor-font-lock-keywords
  `(("#!.*$" . 'factor-font-lock-comment)
    ("!( .* )" . 'factor-font-lock-comment)
    ("^!.*$" . 'factor-font-lock-comment)
    (" !.*$" . 'factor-font-lock-comment)
    ("( .* )" . 'factor-font-lock-stack-effect)
    ("\"\\(\\\\\"\\|[^\"]\\)*\"" . 'factor-font-lock-string)
    ("\\(P\\|SBUF\\)\"" 1 'factor-font-lock-parsing-word)
    ,@(mapcar #'(lambda (w) (cons (concat "\\(^\\| \\)\\(" w "\\)\\($\\| \\)")
                             '(2 'factor-font-lock-parsing-word)))
              factor--parsing-words)
    (,factor--regex-parsing-words-ext . 'factor-font-lock-parsing-word)
    (,factor--regex-word-definition 2 'factor-font-lock-word-definition)
    (,factor--regex-type-definition 2 'factor-font-lock-type-definition)
    (,factor--regex-symbol-definition 2 'factor-font-lock-symbol-definition)
    (,factor--regex-using-line 1 'factor-font-lock-vocabulary-name)
    (,factor--regex-use-line 1 'factor-font-lock-vocabulary-name))
  "Font lock keywords definition for Factor mode.")


;;; Factor mode syntax:

(defvar factor-mode-syntax-table nil
  "Syntax table used while in Factor mode.")

(if factor-mode-syntax-table
    ()
  (let ((i 0))
    (setq factor-mode-syntax-table (make-syntax-table))

    ;; Default is atom-constituent
    (while (< i 256)
      (modify-syntax-entry i "_   " factor-mode-syntax-table)
      (setq i (1+ i)))

    ;; Word components.
    (setq i ?0)
    (while (<= i ?9)
      (modify-syntax-entry i "w   " factor-mode-syntax-table)
      (setq i (1+ i)))
    (setq i ?A)
    (while (<= i ?Z)
      (modify-syntax-entry i "w   " factor-mode-syntax-table)
      (setq i (1+ i)))
    (setq i ?a)
    (while (<= i ?z)
      (modify-syntax-entry i "w   " factor-mode-syntax-table)
      (setq i (1+ i)))

    ;; Whitespace
    (modify-syntax-entry ?\t " " factor-mode-syntax-table)
    (modify-syntax-entry ?\n ">" factor-mode-syntax-table)
    (modify-syntax-entry ?\f " " factor-mode-syntax-table)
    (modify-syntax-entry ?\r " " factor-mode-syntax-table)
    (modify-syntax-entry ?  " " factor-mode-syntax-table)

    (modify-syntax-entry ?\[ "(]  " factor-mode-syntax-table)
    (modify-syntax-entry ?\] ")[  " factor-mode-syntax-table)
    (modify-syntax-entry ?{ "(}  " factor-mode-syntax-table)
    (modify-syntax-entry ?} "){  " factor-mode-syntax-table)

    (modify-syntax-entry ?\( "()" factor-mode-syntax-table)
    (modify-syntax-entry ?\) ")(" factor-mode-syntax-table)
    (modify-syntax-entry ?\" "\"    " factor-mode-syntax-table)))


;;; Factor mode commands:

(defun factor-telnet-to-port (port)
  (interactive "nPort: ")
  (switch-to-buffer
   (make-comint-in-buffer "factor-telnet" nil (cons "localhost" port))))

(defun factor-telnet ()
  (interactive)
  (factor-telnet-to-port 9000))

(defun factor-telnet-factory ()
  (interactive)
  (factor-telnet-to-port 9010))

(defun factor-run-file ()
  (interactive)
  (when (and (buffer-modified-p)
			 (y-or-n-p (format "Save file %s? " (buffer-file-name))))
	(save-buffer))
  (when factor-display-compilation-output
	(factor-display-output-buffer))
  (comint-send-string "*factor*" (format "\"%s\"" (buffer-file-name)))
  (comint-send-string "*factor*" " run-file\n"))

(defun factor-display-output-buffer ()
  (with-current-buffer "*factor*"
	(goto-char (point-max))
	(unless (get-buffer-window (current-buffer) t)
	  (display-buffer (current-buffer) t))))

(defun factor-send-string (str)
  (let ((n (length (split-string str "\n"))))
    (save-excursion
      (set-buffer "*factor*")
      (goto-char (point-max))
      (if (> n 1) (newline))
      (insert str)
      (comint-send-input))))

(defun factor-send-region (start end)
  (interactive "r")
  (let ((str (buffer-substring start end))
        (n   (count-lines      start end)))
    (save-excursion
      (set-buffer "*factor*")
      (goto-char (point-max))
      (if (> n 1) (newline))
      (insert str)
      (comint-send-input))))

(defun factor-send-definition ()
  (interactive)
  (factor-send-region (search-backward ":")
                      (search-forward  ";")))

(defun factor-see ()
  (interactive)
  (comint-send-string "*factor*" "\\ ")
  (comint-send-string "*factor*" (thing-at-point 'sexp))
  (comint-send-string "*factor*" " see\n"))

(defun factor-help ()
  (interactive)
  (comint-send-string "*factor*" "\\ ")
  (comint-send-string "*factor*" (thing-at-point 'sexp))
  (comint-send-string "*factor*" " help\n"))

(defun factor-edit ()
  (interactive)
  (comint-send-string "*factor*" "\\ ")
  (comint-send-string "*factor*" (thing-at-point 'sexp))
  (comint-send-string "*factor*" " edit\n"))

(defun factor-clear ()
  (interactive)
  (factor-send-string "clear"))

(defun factor-comment-line ()
  (interactive)
  (beginning-of-line)
  (insert "! "))

(defvar factor-mode-map (make-sparse-keymap)
  "Key map used by Factor mode.")

(define-key factor-mode-map "\C-c\C-f" 'factor-run-file)
(define-key factor-mode-map "\C-c\C-r" 'factor-send-region)
(define-key factor-mode-map "\C-c\C-d" 'factor-send-definition)
(define-key factor-mode-map "\C-c\C-s" 'factor-see)
(define-key factor-mode-map "\C-ce"    'factor-edit)
(define-key factor-mode-map "\C-c\C-h" 'factor-help)
(define-key factor-mode-map "\C-cc"    'comment-region)
(define-key factor-mode-map [return]   'newline-and-indent)
(define-key factor-mode-map [tab]      'indent-for-tab-command)


;;; Factor mode indentation:

(make-variable-buffer-local
 (defvar factor-indent-width factor-default-indent-width
   "Indentation width in factor buffers. A local variable."))

(defconst factor--regexp-word-start
  (let ((sws '("" ":" "TUPLE" "MACRO" "MACRO:" "M")))
    (format "^\\(%s\\): " (mapconcat 'identity sws "\\|"))))

(defun factor--guess-indent-width ()
  "Chooses an indentation value from existing code."
  (let ((word-cont "^ +[^ ]")
        (iw))
    (save-excursion
      (beginning-of-buffer)
      (while (not iw)
        (if (not (re-search-forward factor--regexp-word-start nil t))
            (setq iw factor-default-indent-width)
          (forward-line)
          (when (looking-at word-cont)
            (setq iw (current-indentation))))))
    iw))

(defsubst factor--ppss-brackets-depth ()
  (nth 0 (syntax-ppss)))

(defsubst factor--ppss-brackets-start ()
  (nth 1 (syntax-ppss)))

(defsubst factor--line-indent (pos)
  (save-excursion (goto-char pos) (current-indentation)))

(defconst factor--regex-closing-paren "[])}]")
(defsubst factor--at-closing-paren-p ()
  (looking-at factor--regex-closing-paren))

(defsubst factor--at-first-char-p ()
  (= (- (point) (line-beginning-position)) (current-indentation)))

(defconst factor--regex-single-liner
  (format "^%s" (regexp-opt '("USE:" "IN:" "PRIVATE>" "<PRIVATE"))))

(defun factor--at-end-of-def ()
  (or (looking-at ".*;[ \t]*$")
      (looking-at factor--regex-single-liner)))

(defun factor--indent-in-brackets ()
  (save-excursion
    (beginning-of-line)
    (when (or (and (re-search-forward factor--regex-closing-paren
                                      (line-end-position) t)
                   (not (backward-char)))
               (> (factor--ppss-brackets-depth) 0))
      (let ((op (factor--ppss-brackets-start)))
        (when (> (line-number-at-pos) (line-number-at-pos op))
          (if (factor--at-closing-paren-p)
              (factor--line-indent op)
            (+ (factor--line-indent op) factor-indent-width)))))))

(defun factor--indent-definition ()
  (save-excursion
    (beginning-of-line)
    (when (looking-at "\\([^ ]\\|^\\)+:") 0)))

(defun factor--indent-continuation ()
  (save-excursion
    (forward-line -1)
    (beginning-of-line)
    (if (bobp) 0
      (if (looking-at "^[ \t]*$")
          (factor--indent-continuation)
        (if (factor--at-end-of-def)
            (- (current-indentation) factor-indent-width)
          (if (factor--indent-definition)
              (+ (current-indentation) factor-indent-width)
            (current-indentation)))))))

(defun factor--calculate-indentation ()
  "Calculate Factor indentation for line at point."
  (or (and (bobp) 0)
      (factor--indent-definition)
      (factor--indent-in-brackets)
      (factor--indent-continuation)
      0))

(defun factor-indent-line ()
  "Indent current line as Factor code"
  (let ((target (factor--calculate-indentation))
        (pos (- (point-max) (point))))
    (if (= target (current-indentation))
        (if (< (current-column) (current-indentation))
            (back-to-indentation))
      (beginning-of-line)
      (delete-horizontal-space)
      (indent-to target)
      (if (> (- (point-max) pos) (point))
          (goto-char (- (point-max) pos))))))


;; Factor mode:

;;;###autoload
(defun factor-mode ()
  "A mode for editing programs written in the Factor programming language.
\\{factor-mode-map}"
  (interactive)
  (kill-all-local-variables)
  (use-local-map factor-mode-map)
  (setq major-mode 'factor-mode)
  (setq mode-name "Factor")
  (set (make-local-variable 'indent-line-function) #'factor-indent-line)
  (set (make-local-variable 'comment-start) "! ")
  (set (make-local-variable 'font-lock-defaults)
       '(factor-font-lock-keywords t nil nil nil))
  (set-syntax-table factor-mode-syntax-table)
  (set (make-local-variable 'indent-line-function) 'factor-indent-line)
  (setq factor-indent-width (factor--guess-indent-width))
  (setq indent-tabs-mode nil)
  (run-hooks 'factor-mode-hook))

(add-to-list 'auto-mode-alist '("\\.factor\\'" . factor-mode))


;;; Factor listener mode

;;;###autoload
(define-derived-mode factor-listener-mode comint-mode "Factor Listener")

(define-key factor-listener-mode-map [f8] 'factor-refresh-all)

;;;###autoload
(defun run-factor ()
  "Start a factor listener inside emacs, or switch to it if it
already exists."
  (interactive)
  (switch-to-buffer
   (make-comint-in-buffer "factor" nil (expand-file-name factor-binary) nil
			  (concat "-i=" (expand-file-name factor-image))
			  "-run=listener"))
  (factor-listener-mode))

(defun factor-refresh-all ()
  "Reload source files and documentation for all loaded
vocabularies which have been modified on disk."
  (interactive)
  (comint-send-string "*factor*" "refresh-all\n"))



(provide 'factor)
;;; factor.el ends here