;;; egison-mode.el --- Egison editing mode

;; Copyright 2011-2013 Satoshi Egi

;;; Author: Satoshi Egi <egisatoshi@gmail.com>
;;; URL: https://github.com/egisatoshi/egison3/blob/master/elisp/egison-mode.el
;;; Version: 0.1.5

;; Code goes here

(defconst egison-font-lock-keywords-1
  (eval-when-compile
    (list
     "\\<define\\>"
     "\\<test\\>"
     "\\<execute\\>"
     "\\<load\\>"
     "\\<load-file\\>"

     "\\<lambda\\>"
     "\\<let\\>"
     "\\<letrec\\>"
     "\\<if\\>"
     "\\<apply\\>"
     "\\<generate-array\\>"
     "\\<array-size\\>"
     "\\<array-ref\\>"

     "\\<loop\\>"
     "\\<match\\>"
     "\\<match-all\\>"
     "\\<matcher\\>"
     "\\<algebraic-data-matcher\\>"
     "\\<match-lambda\\>"
     "\\<pattern-function\\>"

     "\\<do\\>"

     "\\<undefined\\>"
     "\\<something\\>"
     
     "\\\.\\\.\\\."
     "\\\,"
     "\\\!"
     "`"
     "\\\~"
     "\\\#"
     "|"
     "%"
     "\\\&"
     "@"
     "\\<_\\>"
     ))
  "Subdued expressions to highlight in Egison modes.")

(defconst egison-font-lock-keywords-2
  (append egison-font-lock-keywords-1
   (eval-when-compile
     (list
      (cons "\\\$\\\w*" font-lock-variable-name-face)
      )))
  "Gaudy expressions to highlight in Egison modes.")

(defvar egison-font-lock-keywords egison-font-lock-keywords-1
  "Default expressions to highlight in Egison modes.")


(defun open-paren-p ()
  (let ((c (string-to-char (thing-at-point 'char))))
    (or (eq c 40) (eq c 60) (eq c 91) (eq c 123))))

(defun close-paren-p ()
  (let ((c (string-to-char (thing-at-point 'char))))
    (or (eq c 41) (eq c 62) (eq c 93) (eq c 125))))

(defun last-unclosed-paren ()
  (save-excursion
    (let ((pc 0))
      (while (<= pc 0)
        (if (bobp)
            (setq pc 2)
          (backward-char)
          (if (open-paren-p)
              (progn
                (setq pc (+ pc 1))
                (if (and (= pc 0) (= (current-column) 0))
                    (setq pc 2)))
            (if (close-paren-p)
                (setq pc (- pc 1))))))
      (if (= pc 2)
          nil
        (point)))))

(defun indent-point ()
  (save-excursion
    (beginning-of-line)
    (let ((p (last-unclosed-paren)))
      (if p
          (progn
            (goto-char (last-unclosed-paren))
            (let ((cp (current-column)))
              (cond ((eq (string-to-char (thing-at-point 'char)) 40)
                     (forward-char)
                     (let* ((op (current-word))
                            (ip (keyword-indent-point op)))
                       (if ip
                           (+ ip cp)
                         (progn (forward-sexp)
                                (+ 1 (current-column))))))
                    ((eq (string-to-char (thing-at-point 'char)) 60)
                     (forward-char)
                     (let ((op (current-word)))
                       (+ 2 (length op) cp)))
                    ((eq (string-to-char (thing-at-point 'char)) 91)
                     (forward-char)
                     (if (eq (string-to-char (thing-at-point 'char)) 124)
                         (+ 2 cp)
                       (+ 1 cp)))
                    (t (+ 1 cp)))))
        0))))

(defun keyword-indent-point (name)
  (cond ((equal "define" name) 2)
        ((equal "test" name) 2)
        ((equal "load" name) 2)
        ((equal "load-file" name) 2)
        ((equal "execute" name) 2)
        ((equal "lambda" name) 2)
        ((equal "let" name) 2)
        ((equal "letrec" name) 2)
        ((equal "if" name) 2)
        ((equal "apply" name) 2)
        ((equal "generate-array" name) 2)
        ((equal "array-size" name) 2)
        ((equal "array-ref" name) 2)
        ((equal "loop" name) 2)
        ((equal "match" name) 2)
        ((equal "match-all" name) 2)
        ((equal "matcher" name) 2)
        ((equal "algebraic-data-matcher" name) 2)
        ((equal "match-lambda" name) 2)
        ((equal "pattern-function" name) 2)
        ((equal "do" name) 2)
        ))

(defun egison-indent-line ()
  "indent current line as Egison code."
  (interactive)
  (indent-line-to (indent-point)))


(defvar egison-mode-map
  (let ((smap (make-sparse-keymap)))
    (define-key smap "\C-j" 'newline-and-indent)
    smap)
  "Keymap for Egison mode.")


(defvar egison-mode-syntax-table
  (let ((egison-mode-syntax-table (make-syntax-table)))
    (modify-syntax-entry ?< "(" egison-mode-syntax-table)
    (modify-syntax-entry ?> ")" egison-mode-syntax-table)
    (modify-syntax-entry ?\; "<" egison-mode-syntax-table)
    (modify-syntax-entry ?\n ">" egison-mode-syntax-table)
    (modify-syntax-entry ?\? "w" egison-mode-syntax-table)
    (modify-syntax-entry ?# ". 14bn" egison-mode-syntax-table)
    (modify-syntax-entry ?| ". 23bn" egison-mode-syntax-table)
    egison-mode-syntax-table)
  ;; (copy-syntax-table lisp-mode-syntax-table)
  "Syntax table for Egison mode")

(defun egison-mode-variables ()
  (set-syntax-table egison-mode-syntax-table)
  (set (make-local-variable 'font-lock-defaults)
       '((egison-font-lock-keywords
          egison-font-lock-keywords-1 egison-font-lock-keywords-2)
         nil t (("+-*/=?%:_" . "w") ("<" . "(") (">" . ")"))
         ))
  (set (make-local-variable 'indent-line-function) 'egison-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 'comment-end-skip) nil)
  )


(defun egison-mode ()
  "Major mode for editing Egison code.

Commands:
\\{egison-mode-map}
Entry to this mode calls the value of `egison-mode-hook'
if that value is non-nil."
  (interactive)
  (kill-all-local-variables)
  (setq indent-tabs-mode nil)
  (use-local-map egison-mode-map)
  (setq major-mode 'egison-mode)
  (setq mode-name "Egison")
  (egison-mode-variables)
  (run-mode-hooks 'egison-mode-hook))


(defgroup egison nil
  "Editing Egison code."
  :link '(custom-group-link :tag "Font Lock Faces group" font-lock-faces)
  :group 'lisp)

(defcustom egison-mode-hook nil
  "Normal hook run when entering `egison-mode'.
See `run-hooks'."
  :type 'hook
  :group 'egison)

;;; egison-mode.el ends here