2 identifier-smob.cc -- implement glue to pass Scheme expressions off as
5 source file of the GNU LilyPond music typesetter
7 (c) 2002--2003 Han-Wen Nienhuys <hanwen@cs.uu.nl>
10 #include "identifier-smob.hh"
12 C&P from example/box.c
15 scm_t_bits package_tag;
17 /* Print a textual represenation of the smob to a given port. */
19 print_box (SCM b, SCM port, scm_print_state *pstate)
21 SCM value = SCM_CELL_OBJECT_1 (b);
23 scm_puts ("#<packaged object ", port);
24 scm_write (value, port);
27 /* Non-zero means success. */
32 /* This defines the primitve `make-box', which returns a new smob of
33 type `box', initialized to `#f'. */
34 LY_DEFINE(package_identifier, "ly:export", 1,0,0, (SCM arg),
35 "Export a Scheme object to the parser, so it is treated as an identifier.")
37 /* This macro creates the new objects, stores the value `#f' into it
38 and returns it to the caller. */
39 SCM_RETURN_NEWSMOB (package_tag, arg);
43 /* This is the primitive `box-ref' which returns the object stored in
46 unpack_identifier(SCM box)
48 if (SCM_IMP(box) || SCM_CELL_TYPE(box) != package_tag)
51 return SCM_CELL_OBJECT_1 (box);
57 package_tag = scm_make_smob_type ("box", 0);
58 scm_set_smob_mark (package_tag, scm_markcdr);
59 scm_set_smob_print (package_tag, print_box);
61 ADD_SCM_INIT_FUNC(package, init_box_type);