lisp/textmodes/bibtex-style.el

   1 ;;; bibtex-style.el --- Major mode for BibTeX Style files -*- lexical-binding: t -*-
   2
   3 ;; Copyright (C) 2005, 2007-2017 Free Software Foundation, Inc.
   4
   5 ;; Author: Stefan Monnier <monnier@iro.umontreal.ca>
   6 ;; Keywords: tex
   7
   8 ;; This file is part of GNU Emacs.
   9
  10 ;; GNU Emacs is free software: you can redistribute it and/or modify
  11 ;; it under the terms of the GNU General Public License as published by
  12 ;; the Free Software Foundation, either version 3 of the License, or
  13 ;; (at your option) any later version.
  14
  15 ;; GNU Emacs is distributed in the hope that it will be useful,
  16 ;; but WITHOUT ANY WARRANTY; without even the implied warranty of
  17 ;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  18 ;; GNU General Public License for more details.
  19
  20 ;; You should have received a copy of the GNU General Public License
  21 ;; along with GNU Emacs.  If not, see <https://www.gnu.org/licenses/>.
  22
  23 ;;; Commentary:
  24
  25 ;; Done: font-lock, imenu, outline, commenting, indentation.
  26 ;; Todo: tab-completion.
  27 ;; Bugs:
  28
  29 ;;; Code:
  30
  31 (defvar bibtex-style-mode-syntax-table
  32   (let ((st (make-syntax-table)))
  33     (modify-syntax-entry ?%  "<" st)
  34     (modify-syntax-entry ?\n ">" st)
  35     (modify-syntax-entry ?\{ "(}" st)
  36     (modify-syntax-entry ?\} "){" st)
  37     (modify-syntax-entry ?\" "\"" st)
  38     (modify-syntax-entry ?.  "_" st)
  39     (modify-syntax-entry ?'  "'" st)
  40     (modify-syntax-entry ?#  "'" st)
  41     (modify-syntax-entry ?*  "." st)
  42     (modify-syntax-entry ?=  "." st)
  43     (modify-syntax-entry ?$  "_" st)
  44     st))
  45
  46
  47 (defconst bibtex-style-commands
  48   '("ENTRY" "EXECUTE" "FUNCTION" "INTEGERS" "ITERATE" "MACRO" "READ"
  49     "REVERSE" "SORT" "STRINGS"))
  50
  51 (defconst bibtex-style-functions
  52   ;; From http://www.eeng.dcu.ie/local-docs/btxdocs/btxhak/btxhak/node4.html.
  53   '("<" ">" "=" "+" "-" "*" ":="
  54     "add.period$" "call.type$" "change.case$" "chr.to.int$" "cite$"
  55     "duplicate$" "empty$" "format.name$" "if$" "int.to.chr$" "int.to.str$"
  56     "missing$" "newline$" "num.names$" "pop$" "preamble$" "purify$" "quote$"
  57     "skip$" "stack$" "substring$" "swap$" "text.length$" "text.prefix$"
  58     "top$" "type$" "warning$" "while$" "width$" "write$"))
  59
  60 (defvar bibtex-style-font-lock-keywords
  61   `((,(regexp-opt bibtex-style-commands 'words) . font-lock-keyword-face)
  62     ("\\w+\\$" . font-lock-keyword-face)
  63     ("\\<\\(FUNCTION\\|MACRO\\)\\s-+{\\([^}\n]+\\)}"
  64      (2 font-lock-function-name-face))))
  65
  66 ;;;###autoload
  67 (define-derived-mode bibtex-style-mode nil "BibStyle"
  68   "Major mode for editing BibTeX style files."
  69   (set (make-local-variable 'comment-start) "%")
  70   (set (make-local-variable 'outline-regexp) "^[a-z]")
  71   (set (make-local-variable 'imenu-generic-expression)
  72        '((nil "\\<\\(FUNCTION\\|MACRO\\)\\s-+{\\([^}\n]+\\)}" 2)))
  73   (set (make-local-variable 'indent-line-function) 'bibtex-style-indent-line)
  74   (set (make-local-variable 'parse-sexp-ignore-comments) t)
  75   (setq font-lock-defaults
  76         '(bibtex-style-font-lock-keywords nil t
  77           ((?. . "w")))))
  78
  79 (defun bibtex-style-indent-line ()
  80   "Indent current line of BibTeX Style code."
  81   (interactive)
  82   (let* ((savep (point))
  83          (indent (condition-case nil
  84                      (save-excursion
  85                        (forward-line 0)
  86                        (skip-chars-forward " \t")
  87                        (if (>= (point) savep) (setq savep nil))
  88                        (max (bibtex-style-calculate-indentation) 0))
  89                    (error 0))))
  90     (if savep
  91         (save-excursion (indent-line-to indent))
  92       (indent-line-to indent))))
  93
  94 (defcustom bibtex-style-indent-basic 2
  95   "Basic amount of indentation to use in BibTeX Style mode."
  96   :version "22.2"
  97   :type 'integer
  98   :group 'bibtex)
  99
 100 (defun bibtex-style-calculate-indentation (&optional virt)
 101   (or
 102    ;; Stick the first line at column 0.
 103    (and (= (point-min) (line-beginning-position)) 0)
 104    ;; Commands start at column 0.
 105    (and (looking-at (regexp-opt bibtex-style-commands 'words)) 0)
 106    ;; Trust the current indentation, if such info is applicable.
 107    (and virt (save-excursion (skip-chars-backward " \t{") (bolp))
 108         (current-column))
 109    ;; Put leading close-paren where the matching open brace would be.
 110    (and (looking-at "}")
 111         (condition-case nil
 112             (save-excursion
 113               (up-list -1)
 114               (bibtex-style-calculate-indentation 'virt))
 115           (scan-error nil)))
 116    ;; Align leading "if$" with previous command.
 117    (and (looking-at "if\\$")
 118         (condition-case nil
 119             (save-excursion
 120               (backward-sexp 3)
 121               (bibtex-style-calculate-indentation 'virt))
 122           (scan-error
 123            ;; There is no command before the "if$".
 124            (condition-case nil
 125                (save-excursion
 126                  (up-list -1)
 127                  (+ bibtex-style-indent-basic
 128                     (bibtex-style-calculate-indentation 'virt)))
 129              (scan-error nil)))))
 130    ;; Right after an opening brace.
 131    (condition-case err (save-excursion (backward-sexp 1) nil)
 132      (scan-error (goto-char (nth 2 err))
 133                  (+ bibtex-style-indent-basic
 134                     (bibtex-style-calculate-indentation 'virt))))
 135    ;; Default, align with previous command.
 136    (let ((fai ;; First arm of an "if$".
 137           (condition-case nil
 138               (save-excursion
 139                 (forward-sexp 2)
 140                 (forward-comment (point-max))
 141                 (looking-at "if\\$"))
 142             (scan-error nil))))
 143      (save-excursion
 144        (condition-case nil
 145            (while (progn
 146                     (backward-sexp 1)
 147                     (save-excursion (skip-chars-backward " \t{") (not (bolp)))))
 148          (scan-error nil))
 149        (+ (current-column)
 150           (if (or fai (looking-at "ENTRY")) bibtex-style-indent-basic 0))))))
 151
 152
 153 (provide 'bibtex-style)
 154 ;;; bibtex-style.el ends here