lily/identifier-smob.cc

   1 /*
   2   This file is part of LilyPond, the GNU music typesetter.
   3
   4   Copyright (C) 2002--2011 Han-Wen Nienhuys <hanwen@xs4all.nl>
   5
   6   LilyPond is free software: you can redistribute it and/or modify
   7   it under the terms of the GNU General Public License as published by
   8   the Free Software Foundation, either version 3 of the License, or
   9   (at your option) any later version.
  10
  11   LilyPond is distributed in the hope that it will be useful,
  12   but WITHOUT ANY WARRANTY; without even the implied warranty of
  13   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14   GNU General Public License for more details.
  15
  16   You should have received a copy of the GNU General Public License
  17   along with LilyPond.  If not, see <http://www.gnu.org/licenses/>.
  18 */
  19
  20 #include "identifier-smob.hh"
  21
  22 scm_t_bits package_tag;
  23
  24 static int
  25 print_box (SCM b, SCM port, scm_print_state *)
  26 {
  27   SCM value = SCM_CELL_OBJECT_1 (b);
  28
  29   scm_puts ("#<packaged object ", port);
  30   scm_write (value, port);
  31   scm_puts (">", port);
  32
  33   /* Non-zero means success.  */
  34   return 1;
  35 }
  36
  37 /* This defines the primitve `make-box', which returns a new smob of
  38    type `box', initialized to `#f'.  */
  39 LY_DEFINE (ly_export, "ly:export",
  40            1, 0, 0, (SCM arg),
  41            "Export a Scheme object to the parser"
  42            " so it is treated as an identifier.")
  43 {
  44   SCM_RETURN_NEWSMOB (package_tag, arg);
  45 }
  46
  47 SCM
  48 unpack_identifier (SCM box)
  49 {
  50   if (SCM_IMP (box) || SCM_CELL_TYPE (box) != package_tag)
  51     return SCM_UNDEFINED;
  52
  53   return SCM_CELL_OBJECT_1 (box);
  54 }
  55
  56 static void
  57 init_box_type (void)
  58 {
  59   package_tag = scm_make_smob_type ("box", 0);
  60   scm_set_smob_mark (package_tag, scm_markcdr);
  61   scm_set_smob_print (package_tag, print_box);
  62 }
  63
  64 ADD_SCM_INIT_FUNC (package, init_box_type);