fulcrum-mode.el

;;; fulcrum-mode.el --- Major mode for Fulcrum code -*- lexical-binding: t; -*-

;; Copyright © 2022 Alexey Egorov
;; Copyright © 2023 Alexey Egorov, Lämppi Lütti

;; Authors: Alexey Egorov <alexey.e.egorov@gmail.com>
;;       Lämppi Lütti <lamppilutti@gmail.com>
;; Maintainer: Lämppi Lütti <lamppilutti@gmail.com>
;; Version: 0.0.1
;; Package-Requires: ((emacs "26.3"))
;; Keywords: languages
;; URL: http://github.com/koto-bank/fulcrum-mode

;; This file is not part of GNU Emacs.

;;; License:

;; 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 <https://www.gnu.org/licenses/>.

;;; Commentary:

;;; Code:

(require 'lisp-mode)

(defgroup fulcrum-mode nil
  "Major mode for Fulcrum code."
  :prefix 'fulcrum-
  :group 'languages)


(define-abbrev-table 'fulcrum-mode-abbrev-table ()
  "Abbrev table for Fulcrum mode.
It has `lisp-mode-abbrev-table' as its parent."
  :parents (list lisp-mode-abbrev-table))

(defvar fulcrum-mode-syntax-table
  (let ((table (make-syntax-table lisp-data-mode-syntax-table)))
    table))

(defvar fulcrum-mode-map
  (let ((map (make-sparse-keymap)))
    (set-keymap-parent map lisp-mode-shared-map)
    map)
  "Keymap for Fulcrum mode.
All commands in `lisp-mode-shared-map' are inherited by this map.")

(defvar fulcrum-mode-line-process "")

(defconst fulcrum-font-lock-keywords
  (eval-when-compile
    (list
     ;; Declarations
     (list (concat "("
                   (regexp-opt '("module"
                                 "fn"
                                 "fn-"
                                 "struct"
                                 "struct-"
                                 "var")
                               'word)
                   "\\>"
                   "[[:space:]]*"
                   "\\([[:word:]]*\\)")
           '(1 font-lock-keyword-face)
           '(2 font-lock-function-name-face))
     ;; Special forms
     (list (concat "("
                   (regexp-opt '("if"
                                 "do"
                                 "while"
                                 "unless"
                                 "return")
                               'word)
                   "\\>")
           '(1 'font-lock-builtin-face)))))

(defun fulcrum-mode-set-variables ()
  (set-syntax-table fulcrum-mode-syntax-table)
  (setq local-abbrev-table fulcrum-mode-abbrev-table)
  (setq mode-line-process '("" fulcrum-mode-line-process))
  (setq font-lock-defaults
        '((fulcrum-font-lock-keywords)
          nil nil
          (("+-*/.<>=!?$%_&:" . "w"))
          nil
          (font-lock-mark-block-function . mark-defun)))
  (setq-local prettify-symbols-alist lisp-prettify-symbols-alist))

(put 'fn 'lisp-indent-function 'defun)
(put 'fn- 'lisp-indent-function 'defun)
(put 'module 'lisp-indent-function 'defun)
(put 'var 'lisp-indent-function 0)

;;;###autoload
(define-derived-mode fulcrum-mode lisp-data-mode "Fulcrum"
  "Major mode for editing Fulcrum code.
Editing commands are similar to those of `lisp-mode'.

Commands:
Delete converts tabs to spaces as it moves back.
Blank lines separate paragraphs.  Semicolons start comments.
\\{fulcrum-mode-map}"
  :group 'fulcrum-mode
  (fulcrum-mode-set-variables))

;;;###autoload
(add-to-list 'auto-mode-alist '("\\.\\(fc\\|fulcrum\\)\\'" . fulcrum-mode))

(provide 'fulcrum-mode)

;;; fulcrum-mode.el ends here.