Imported Upstream version 2.16.0

[lilypond.git] / scm / safe-utility-defs.scm

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+;;;; This file is part of LilyPond, the GNU music typesetter.
+;;;;
+;;;; Copyright (C) 1998--2012 Jan Nieuwenhuizen <janneke@gnu.org>
+;;;; Han-Wen Nienhuys <hanwen@xs4all.nl>
+;;;;
+;;;; LilyPond 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.
+;;;;
+;;;; LilyPond 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 LilyPond.  If not, see <http://www.gnu.org/licenses/>.
+;;;
+;;;      Author Ian Hulin
+;;;      Date   16 October 2011
+;;;
+ 
+(define-module (scm safe-utility-defs)
+#:use-module (ice-9 optargs)
+#:export (safe-objects)
+#:export-syntax (define-safe-public)
+#:re-export-syntax (define*-public))
+
+;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
+;; Safe definitions utility
+
+(define safe-objects
+  (list))
+
+(define (get-symbol arg)
+  (if (pair? arg)
+      (get-symbol (car arg))
+      arg))
+
+
+(define-macro (define-safe-public arglist . body)
+  "Define a variable, export it, and mark it as safe, i.e. usable in
+LilyPond safe mode.  The syntax is the same as `define*-public'."
+
+  (let ((safe-symbol (get-symbol arglist)))
+    `(begin
+       (define*-public ,arglist
+         ,@body)
+       (set! safe-objects (cons (cons ',safe-symbol ,safe-symbol)
+                                safe-objects))
+       ,safe-symbol)))