xref: /third_party/ninja/misc/ninja-mode.el (revision 695b41ee)
1;;; ninja-mode.el --- Major mode for editing .ninja files -*- lexical-binding: t -*-
2
3;; Package-Requires: ((emacs "24"))
4
5;; Copyright 2011 Google Inc. All Rights Reserved.
6;;
7;; Licensed under the Apache License, Version 2.0 (the "License");
8;; you may not use this file except in compliance with the License.
9;; You may obtain a copy of the License at
10;;
11;;     http://www.apache.org/licenses/LICENSE-2.0
12;;
13;; Unless required by applicable law or agreed to in writing, software
14;; distributed under the License is distributed on an "AS IS" BASIS,
15;; WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
16;; See the License for the specific language governing permissions and
17;; limitations under the License.
18
19;;; Commentary:
20
21;; Simple emacs mode for editing .ninja files.
22
23;;; Code:
24
25(defcustom ninja-indent-offset 2
26  "*Amount of offset per level of indentation."
27  :type 'integer
28  :safe 'natnump
29  :group 'ninja)
30
31(defconst ninja-keywords-re
32  (concat "^" (regexp-opt '("rule" "build" "subninja" "include" "pool" "default")
33                          'words)))
34
35(defvar ninja-keywords
36  `((,ninja-keywords-re . font-lock-keyword-face)
37    ("^[[:space:]]*\\([[:alnum:]_]+\\)[[:space:]]*=" 1 font-lock-variable-name-face)
38    ;; Variable expansion.
39    ("$[[:alnum:]_]+" . font-lock-variable-name-face)
40    ("${[[:alnum:]._]+}" . font-lock-variable-name-face)
41    ;; Rule names
42    ("rule +\\([[:alnum:]_.-]+\\)" 1 font-lock-function-name-face)
43    ;; Build Statement - highlight the rule used,
44    ;; allow for escaped $,: in outputs.
45    ("build +\\(?:[^:$\n]\\|$[:$]\\)+ *: *\\([[:alnum:]_.-]+\\)"
46     1 font-lock-function-name-face)))
47
48(defvar ninja-mode-syntax-table
49  (let ((table (make-syntax-table)))
50    (modify-syntax-entry ?\" "." table)
51    table)
52  "Syntax table used in `ninja-mode'.")
53
54(defun ninja-syntax-propertize (start end)
55  (save-match-data
56    (goto-char start)
57    (while (search-forward "#" end t)
58      (let ((match-pos (match-beginning 0)))
59        (when (and
60               ;; Is it the first non-white character on the line?
61               (eq match-pos (save-excursion (back-to-indentation) (point)))
62               (save-excursion
63                 (goto-char (line-end-position 0))
64                 (or
65                  ;; If we're continuing the previous line, it's not a
66                  ;; comment.
67                  (not (eq ?$ (char-before)))
68                  ;; Except if the previous line is a comment as well, as the
69                  ;; continuation dollar is ignored then.
70                  (nth 4 (syntax-ppss)))))
71          (put-text-property match-pos (1+ match-pos) 'syntax-table '(11))
72          (let ((line-end (line-end-position)))
73            ;; Avoid putting properties past the end of the buffer.
74            ;; Otherwise we get an `args-out-of-range' error.
75            (unless (= line-end (1+ (buffer-size)))
76              (put-text-property line-end (1+ line-end) 'syntax-table '(12)))))))))
77
78(defun ninja-compute-indentation ()
79  "Calculate indentation for the current line."
80  (save-excursion
81    (beginning-of-line)
82    (if (or (looking-at ninja-keywords-re)
83            (= (line-number-at-pos) 1))
84        0
85      (forward-line -1)
86      (if (looking-at ninja-keywords-re)
87          ninja-indent-offset
88        (current-indentation)))))
89
90(defun ninja-indent-line ()
91  "Indent the current line.  Uses previous indentation level if
92 available or `ninja-indent-offset'"
93  (interactive "*")
94  (indent-line-to (ninja-compute-indentation)))
95
96;;;###autoload
97(define-derived-mode ninja-mode prog-mode "ninja"
98  (set (make-local-variable 'comment-start) "#")
99  (set (make-local-variable 'parse-sexp-lookup-properties) t)
100  (set (make-local-variable 'syntax-propertize-function) #'ninja-syntax-propertize)
101  (set (make-local-variable 'indent-line-function) 'ninja-indent-line)
102  (setq font-lock-defaults '(ninja-keywords)))
103
104;; Run ninja-mode for files ending in .ninja.
105;;;###autoload
106(add-to-list 'auto-mode-alist '("\\.ninja$" . ninja-mode))
107
108(provide 'ninja-mode)
109
110;;; ninja-mode.el ends here
111