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ob-svgbob.el

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+;;; ob-svgbob.el --- Babel Functions for SVGBob -*- lexical-binding: t; -*-
+
+;; Copyright (C) 2021 Free Software Foundation, Inc.
+
+;; Authors: Steven vanZyl <rushsteve1@rushsteve1.us>
+;;          TEC <tec@tecosaur.net>
+;; Maintainer: Timothy <tec@tecosaur.net>
+;; Keywords: literate programming, reproducible research
+;; Homepage: https://git.tecosaur.net/tec/ob-svgbob
+
+;; This file is not part of GNU Emacs.
+
+;; ob-svgbob 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.
+
+;; ob-svgbob 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 ob-svgbob.  If not, see <https://www.gnu.org/licenses/>.
+
+;;; Commentary:
+
+;; Org-Babel support for evaluating and SVGBob diagrams.
+;; https://github.com/ivanceras/svgbob
+
+;; This is very similar to ob-dot.el with a similar list of caveats:
+
+;; * There are no sessions
+;; * We are generally only going to return results of type "file graphics"
+;; * The "file" header argument is required
+;; * SVGBob has no definite syntax
+
+;; This file also includes some additional utility functions and a simple
+;; derived major-mode for SVGBob
+
+;;; Code:
+
+(require 'ob)
+
+(defcustom org-svgbob-executable "svgbob"
+  "The path to the SVGBob binary.
+This can be installed from source using `cargo install svgbob_cli'"
+  :group 'org-babel
+  :type 'file)
+
+(defcustom org-svgbob-buffer-name "*svgbob-output*"
+  "The name of the buffer that SVGBob will output to."
+  :group 'org-babel
+  :type 'string)
+
+(defcustom org-babel-svgbob-options
+  '((background . "transparent"))
+  "Options passed to the SVGBob executable."
+  :group 'org-babel
+  :type '(alist :value-type (symbol string)))
+
+;; So `org-edit-special' works.
+;; Since SVGBob is based on simple ASCII diagrams without a definite, this mode
+;; is derived from `artist-mode'.
+(unless (fboundp 'svgbob-mode)
+  (define-derived-mode svgbob-mode artist-mode "svgbob"))
+
+(defun ob-svgbob-string-to-svg (str)
+  "Convert STR to SVG text and return a string of that."
+  (org-babel-eval
+   (concat svgbob-executable " "
+           (mapconcat (lambda (opt) (format "--%s %s " (symbol-name (car opt)) (cdr opt)))
+                      org-babel-svgbob-options
+                      " "))
+   str))
+
+(defun ob-svgbob-region-to-svg (start end)
+  "Convert a region to SVG text in a new buffer.
+The region is given by the range START to END."
+  (interactive "r")
+  (let ((str (ob-svgbob-string-to-svg (buffer-substring-no-properties start end))))
+    (with-current-buffer (get-buffer-create org-svgbob-buffer-name)
+      (read-only-mode 0) ; Disable read-only
+      (fundamental-mode) ; Required to erase the buffer
+      (erase-buffer)
+      (insert str)
+      (image-mode)
+      (read-only-mode)
+      (display-buffer-in-side-window (current-buffer) '((side . right))))))
+
+(defun ob-svgbob-buffer-to-svg ()
+  "Convert a buffer to SVG text in a new buffer.
+See `svgbob-region-to-svg' for more"
+  (interactive)
+  (ob-svgbob-region-to-svg (point-min) (point-max)))
+
+(defvar org-babel-default-header-args:svgbob
+  '((:results . "file graphics") (:exports . "results"))
+  "Default arguments to use when evaluating a dot source block.")
+
+(defun org-babel-execute:svgbob (body params)
+  "Execute a block of svgbob with org-babel.
+Specifically, svgbob is called on BODY with PARAMS."
+  (if (alist-get :file params)
+      (ob-svgbob-string-to-svg body)
+    (user-error "You need to specify a :file parameter")))
+
+(defun org-babel-prep-session:svgbob (_session _params)
+  "Return an error because SVGBob does not support sessions."
+  (user-error "SVGBob does not support sessions"))
+
+(provide 'ob-svgbob)
+
+;;; ob-svgbob.el ends here