1 ;;; 9ps-mode.el --- major mode for editing ninepscripts  -*- lexical-binding: t; -*-
2 
3 ;; Copyright (C) 2021  Omar Polo
4 
5 ;; Author: Omar Polo <op@omarpolo.com>
6 ;; Keywords: languages
7 
8 ;; Permission to use, copy, modify, and distribute this software for any
9 ;; purpose with or without fee is hereby granted, provided that the above
10 ;; copyright notice and this permission notice appear in all copies.
11 
12 ;; THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
13 ;; WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
14 ;; MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
15 ;; ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
16 ;; WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
17 ;; ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
18 ;; OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
19 
20 ;;; Commentary:
21 
22 ;; Major mode for editing ninepscripts, the kamid regression tests.
23 
24 ;;; Code:
25 (eval-when-compile
26   (require 'rx))
27 
28 (defconst 9ps-keywords
29   '("assert" "const" "dir" "include" "proc" "str" "testing"
30     "u8" "u16" "u32"))
31 
32 (defconst 9ps--font-lock-keywords
33   (list
34    (rx-to-string
35     `(: (or ,@9ps-keywords))))
36   "`9ps-mode' constant keywords.")
37 
38 (defvar 9ps-mode-syntax-table
39   (let ((st (make-syntax-table)))
40     (modify-syntax-entry ?\{ "(}" st)
41     (modify-syntax-entry ?\} "){" st)
42     (modify-syntax-entry ?\( "()" st)
43     ;; - and _ are word constituent
44     (modify-syntax-entry ?_ "w" st)
45     (modify-syntax-entry ?- "w" st)
46     ;; both single and double quotes makes strings
47     (modify-syntax-entry ?\" "\"" st)
48     (modify-syntax-entry ?' "'" st)
49     ;; one day we'll have escaping (maybe)
50     (modify-syntax-entry ?\\ "\\" st)
51     ;; add comments.  is this the correct way?
52     (modify-syntax-entry ?# "<" st)
53     (modify-syntax-entry ?\n ">" st)
54     st))
55 
56 (defun 9ps-indent-line ()
57   "Indent current line."
58   (let (indent
59         boi-p                           ;begin of indent
60         move-eol-p
61         (point (point)))
62     (save-excursion
63       (back-to-indentation)
64       (setq indent (car (syntax-ppss))
65             boi-p (= point (point)))
66       ;; don't indent empty lines, but only when they don't have the
67       ;; cursor in it.
68       (when (and (eq (char-after) ?\n)
69                  (not boi-p))
70         (setq indent 0))
71       ;; check whether we want to move to the end of line
72       (when (and (eq (char-after) ?\n)
73                  boi-p)
74         (setq move-eol-p t))
75       ;; decrement the indent if the first character on the line is a
76       ;; closer.
77       (when (or (eq (char-after) ?\))
78                 (eq (char-after) ?\}))
79         (setq indent (1- indent)))
80       ;; indent the line
81       (delete-region (line-beginning-position)
82                      (point))
83       (indent-to (* tab-width indent)))
84     (when move-eol-p
85       (move-end-of-line nil))))
86 
87 ;;;###autoload
88 (define-derived-mode 9ps-mode prog-mode "9ps"
89   "Major mode for ninepscript files."
90   (setq font-lock-defaults '((9ps--font-lock-keywords)))
91   (setq-local comment-start "#")
92   (setq-local comment-start-skip "#+[\t ]*")
93   (setq-local indent-line-function #'9ps-indent-line))
94 
95 ;;;###autoload
96 (add-to-list 'auto-mode-alist '("\\.9ps" . 9ps-mode))
97 
98 (provide '9ps-mode)
99 ;;; 9ps-mode.el ends here