--- /dev/null
+## Process this file with Automake to create Makefile.in
+##
+## Copyright (C) 2001 Free Software Foundation, Inc.
+##
+## This file is part of GUILE.
+##
+## GUILE 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 2, or
+## (at your option) any later version.
+##
+## GUILE 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 GUILE; see the file COPYING. If not, write
+## to the Free Software Foundation, Inc., 59 Temple Place, Suite
+## 330, Boston, MA 02111-1307 USA
+
+EXTRA_DIST = README box.c
+
+CFLAGS=`guile-config compile`
+LIBS=`guile-config link`
+
+libbox: box.lo
+ sh ../../libtool --mode=link $(CC) $< $(LIBS) -rpath $(prefix)/lib -o libbox.la
+
+box.lo: box.c
+ sh ../../libtool --mode=compile $(CC) $(CFLAGS) -c $<
\ No newline at end of file
--- /dev/null
+ -*- text -*-
+
+This directory includes an example program for extending Guile with a
+new (and even useful) data type, putting it into a shared library, so it
+can be called from an unmodified guile interpreter.
+
+To build the example, simply type
+
+ make libbox
+
+in this directory.
+
+A box is simply an object for storing one other object in. It can be
+used for passing parameters by reference, for example. You simply
+store an object into a box, pass it to another procedure which can
+store a new object into it and thus return a value via the box.
+
+Box objects are created with `make-box', set with `box-set!' and
+examined with `box-ref'. Note that these procedures are placed in a
+module called (box-module) and can thus only be accessed after using
+this module. See the following example session for usage details:
+
+Extend your LD_LIBRARY_PATH variable (or equivalent) to include . and
+.libs
+
+If you like this example so much that you want to have it available
+for normal usage, install the dynamic libraries in the .libs directory
+to the directory $(prefix)/lib
+
+$ ./guile
+guile> (load-extension "libbox" "scm_init_box")
+guile> (define b (make-box))
+guile> b
+#<box #f>
+guile> (box-set! b '(list of values))
+guile> b
+#<box (list of values)>
+guile> (box-ref b)
+(list of values)
+guile> (quit)
+$
--- /dev/null
+/* examples/box-dynamic/box.c
+ *
+ * Copyright (C) 1998,2001 Free Software Foundation, Inc.
+ *
+ * This program 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 2, or (at your option)
+ * any later version.
+ *
+ * This program 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 this software; see the file COPYING. If not, write to
+ * the Free Software Foundation, Inc., 59 Temple Place, Suite 330,
+ * Boston, MA 02111-1307 USA
+ */
+
+/* Include all needed declarations. */
+#include <libguile.h>
+
+
+/* The type code for the newly created smob type will be stored into
+ this variable. It has the prefix `scm_tc16_' to make it usable
+ with the SCM_VALIDATE_SMOB macro below. */
+static scm_bits_t scm_tc16_box;
+
+
+/* This function is responsible for marking all SCM objects included
+ in the smob. */
+static SCM
+mark_box (SCM b)
+{
+ /* Since we have only one SCM object to protect, we simply return it
+ and the caller with mark it. */
+ return SCM_CELL_OBJECT_1 (b);
+}
+
+
+/* Print a textual represenation of the smob to a given port. */
+static int
+print_box (SCM b, SCM port, scm_print_state *pstate)
+{
+ SCM value = SCM_CELL_OBJECT_1 (b);
+
+ scm_puts ("#<box ", port);
+ scm_write (value, port);
+ scm_puts (">", port);
+
+ /* Non-zero means success. */
+ return 1;
+}
+
+
+/* This defines the primitve `make-box', which returns a new smob of
+ type `box', initialized to `#f'. */
+static SCM
+#define FUNC_NAME "make-box"
+make_box (void)
+{
+ /* This macro creates the new objects, stores the value `#f' into it
+ and returns it to the caller. */
+ SCM_RETURN_NEWSMOB (scm_tc16_box, SCM_BOOL_F);
+}
+#undef FUNC_NAME
+
+
+/* This is the primitive `box-ref' which returns the object stored in
+ the box. */
+static SCM
+box_ref (SCM b)
+#define FUNC_NAME "box-ref"
+{
+ /* First, we have to ensure that the user really gave us a box
+ objects. The macro SCM_VALIDATE_SMOB will do all what is needed.
+ The parameters are interpreted as follows:
+
+ 1: The position of the checked variable in the parameter list.
+ b: The passed parameter.
+ box: Concatenated with the fixed prefix scm_tc16_, names the type
+ code for the expected smob type. */
+ SCM_VALIDATE_SMOB (1, b, box);
+
+ /* Fetch the object from the box and return it. */
+ return SCM_CELL_OBJECT_1 (b);
+}
+#undef FUNC_NAME
+
+
+/* Primitive which stores an arbitrary value into a box. */
+static SCM
+box_set_x (SCM b, SCM value)
+#define FUNC_NAME "box-set!"
+{
+ SCM_VALIDATE_SMOB (1, b, box);
+
+ /* Set the cell number 1 of the smob to the given value. */
+ SCM_SET_CELL_OBJECT_1 (b, value);
+
+ /* When this constant is returned, the REPL will not print the
+ returned value. All procedures in Guile which are documented as
+ returning `and unspecified value' actually return this value. */
+ return SCM_UNSPECIFIED;
+}
+#undef FUNC_NAME
+
+
+/* Create and initialize the new smob type, and register the
+ primitives with the interpreter library.
+
+ To be called with (load-extension "libbox" "scm_init_box")
+ from a script.
+*/
+void
+scm_init_box ()
+{
+ scm_tc16_box = scm_make_smob_type ("box", 0);
+ scm_set_smob_mark (scm_tc16_box, mark_box);
+ scm_set_smob_print (scm_tc16_box, print_box);
+
+ scm_c_define_gsubr ("make-box", 0, 0, 0, make_box);
+ scm_c_define_gsubr ("box-set!", 2, 0, 0, box_set_x);
+ scm_c_define_gsubr ("box-ref", 1, 0, 0, box_ref);
+}
+
+/* End of file. */
HCoop / bpt / guile.git / commitdiff