lisp/ob-ebnf.el

   1 ;;; ob-ebnf.el --- Babel Functions for EBNF          -*- lexical-binding: t; -*-
   2
   3 ;; Copyright (C) 2013-2019 Free Software Foundation, Inc.
   4
   5 ;; Author: Michael Gauland
   6 ;; Keywords: literate programming, reproducible research
   7 ;; Homepage: https://orgmode.org
   8 ;; Version: 1.00
   9
  10 ;; This file is part of GNU Emacs.
  11
  12 ;; GNU Emacs is free software: you can redistribute it and/or modify
  13 ;; it under the terms of the GNU General Public License as published by
  14 ;; the Free Software Foundation, either version 3 of the License, or
  15 ;; (at your option) any later version.
  16
  17 ;; GNU Emacs is distributed in the hope that it will be useful,
  18 ;; but WITHOUT ANY WARRANTY; without even the implied warranty of
  19 ;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  20 ;; GNU General Public License for more details.
  21
  22 ;; You should have received a copy of the GNU General Public License
  23 ;; along with GNU Emacs.  If not, see <https://www.gnu.org/licenses/>.
  24
  25 ;;; Commentary:
  26
  27 ;;; Org-Babel support for using ebnf2ps to generate encapsulated postscript
  28 ;;; railroad diagrams. It recognizes these arguments:
  29 ;;;
  30 ;;;     :file is required; it must include the extension '.eps.' All the rules
  31 ;;;           in the block will be drawn in the same file. This is done by
  32 ;;;           inserting a '[<file>' comment at the start of the block (see the
  33 ;;;           documentation for ebnf-eps-buffer for more information).
  34 ;;;
  35 ;;;     :style specifies a value in ebnf-style-database. This provides the
  36 ;;;            ability to customize the output. The style can also specify the
  37 ;;;            grammar syntax (by setting ebnf-syntax); note that only ebnf,
  38 ;;;            iso-ebnf, and yacc are supported by this file.
  39
  40 ;;; Requirements:
  41
  42 ;;; Code:
  43 (require 'ob)
  44 (require 'ebnf2ps)
  45
  46 ;; optionally declare default header arguments for this language
  47 (defvar org-babel-default-header-args:ebnf '((:style . nil)))
  48
  49 ;; Use ebnf-eps-buffer to produce an encapsulated postscript file.
  50 ;;
  51 (defun org-babel-execute:ebnf (body params)
  52   "Execute a block of Ebnf code with org-babel.  This function is
  53 called by `org-babel-execute-src-block'"
  54   (save-excursion
  55     (let* ((dest-file (cdr (assq :file params)))
  56            (dest-dir (file-name-directory dest-file))
  57            (dest-root (file-name-sans-extension
  58                        (file-name-nondirectory dest-file)))
  59            (style (cdr (assq :style params)))
  60            (result nil))
  61       (with-temp-buffer
  62         (when style (ebnf-push-style style))
  63         (let ((comment-format
  64                (cond ((string= ebnf-syntax 'yacc) "/*%s*/")
  65                      ((string= ebnf-syntax 'ebnf) ";%s")
  66                      ((string= ebnf-syntax 'iso-ebnf) "(*%s*)")
  67                      (t (setq result
  68                               (format "EBNF error: format %s not supported."
  69                                       ebnf-syntax))))))
  70           (setq ebnf-eps-prefix dest-dir)
  71           (insert (format comment-format (format "[%s" dest-root)))
  72           (newline)
  73           (insert body)
  74           (newline)
  75           (insert (format comment-format (format "]%s" dest-root)))
  76           (ebnf-eps-buffer)
  77           (when style (ebnf-pop-style))))
  78       result)))
  79
  80 (provide 'ob-ebnf)
  81 ;;; ob-ebnf.el ends here