--- /dev/null
+/* Copyright (C) 1995,1996,1998,2000,2001, 2006, 2008 Free Software Foundation
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ *
+ * This library 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
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
+ */
+
+\f
+#ifdef HAVE_CONFIG_H
+# include <config.h>
+#endif
+
+#include "libguile/_scm.h"
+#include "libguile/mallocs.h"
+#include "libguile/strings.h"
+#include "libguile/lang.h"
+
+#include "libguile/options.h"
+\f
+
+/* {Run-time options}
+ *
+ * This is the basic interface for low-level configuration of the
+ * Guile library. It is used for configuring the reader, evaluator,
+ * printer and debugger.
+ *
+ * Motivation:
+ *
+ * 1. Altering option settings can have side effects.
+ * 2. Option values can be stored in native format.
+ * (Important for efficiency in, e. g., the evaluator.)
+ * 3. Doesn't use up name space.
+ * 4. Options can be naturally grouped => ease of use.
+ */
+
+/* scm_options is the core of all options interface procedures.
+ *
+ * Some definitions:
+ *
+ * Run time options in Guile are arranged in groups. Each group
+ * affects a certain aspect of the behaviour of the library.
+ *
+ * An "options interface procedure" manages one group of options. It
+ * can be used to check or set options, or to get documentation for
+ * all options of a group. The options interface procedure is not
+ * intended to be called directly by the user. The user should
+ * instead call
+ *
+ * (<group>-options)
+ * (<group>-options 'help)
+ * (<group>-options 'full)
+ *
+ * to display current option settings (The second version also
+ * displays documentation. The third version also displays
+ * information about programmer's options.), and
+ *
+ * (<group>-enable '<option-symbol>)
+ * (<group>-disable '<option-symbol>)
+ * (<group>-set! <option-symbol> <value>)
+ * (<group>-options <option setting>)
+ *
+ * to alter the state of an option (The last version sets all
+ * options according to <option setting>.) where <group> is the name
+ * of the option group.
+ *
+ * An "option setting" represents the state of all low-level options
+ * managed by one options interface procedure. It is a list of
+ * single symbols and symbols followed by a value.
+ *
+ * For boolean options, the presence of the symbol of that option in
+ * the option setting indicates a true value. If the symbol isn't a
+ * member of the option setting this represents a false value.
+ *
+ * Other options are represented by a symbol followed by the value.
+ *
+ * If scm_options is called without arguments, the current option
+ * setting is returned. If the argument is an option setting, options
+ * are altered and the old setting is returned. If the argument isn't
+ * a list, a list of sublists is returned, where each sublist contains
+ * option name, value and documentation string.
+ */
+
+SCM_SYMBOL (scm_yes_sym, "yes");
+SCM_SYMBOL (scm_no_sym, "no");
+
+static SCM protected_objects = SCM_EOL;
+
+/* Return a list of the current option setting. The format of an
+ * option setting is described in the above documentation. */
+static SCM
+get_option_setting (const scm_t_option options[], unsigned int n)
+{
+ unsigned int i;
+ SCM ls = SCM_EOL;
+ for (i = 0; i != n; ++i)
+ {
+ switch (options[i].type)
+ {
+ case SCM_OPTION_BOOLEAN:
+ if (options[i].val)
+ ls = scm_cons (SCM_PACK (options[i].name), ls);
+ break;
+ case SCM_OPTION_INTEGER:
+ ls = scm_cons (scm_from_unsigned_integer (options[i].val), ls);
+ ls = scm_cons (SCM_PACK (options[i].name), ls);
+ break;
+ case SCM_OPTION_SCM:
+ ls = scm_cons (SCM_PACK (options[i].val), ls);
+ ls = scm_cons (SCM_PACK (options[i].name), ls);
+ }
+ }
+ return ls;
+}
+
+
+/* Return a list of sublists, where each sublist contains option name, value
+ * and documentation string. */
+static SCM
+get_documented_option_setting (const scm_t_option options[], unsigned int n)
+{
+ SCM ans = SCM_EOL;
+ unsigned int i;
+
+ for (i = 0; i != n; ++i)
+ {
+ SCM ls = scm_cons (scm_from_locale_string (options[i].doc), SCM_EOL);
+ switch (options[i].type)
+ {
+ case SCM_OPTION_BOOLEAN:
+ ls = scm_cons (options[i].val ? scm_yes_sym : scm_no_sym, ls);
+ break;
+ case SCM_OPTION_INTEGER:
+ ls = scm_cons (scm_from_unsigned_integer (options[i].val), ls);
+ break;
+ case SCM_OPTION_SCM:
+ ls = scm_cons (SCM_PACK (options[i].val), ls);
+ }
+ ls = scm_cons (SCM_PACK (options[i].name), ls);
+ ans = scm_cons (ls, ans);
+ }
+ return ans;
+}
+
+
+/* Alters options according to the given option setting 'args'. The value of
+ * args is known to be a list, but it is not known whether the list is a well
+ * formed option setting, i. e. if for every non-boolean option a value is
+ * given. For this reason, the function applies all changes to a copy of the
+ * original setting in memory. Only if 'args' was successfully processed,
+ * the new setting will overwrite the old one. */
+static void
+change_option_setting (SCM args, scm_t_option options[], unsigned int n, const char *s)
+{
+ unsigned int i;
+ SCM locally_protected_args = args;
+ SCM malloc_obj = scm_malloc_obj (n * sizeof (scm_t_bits));
+ scm_t_bits *flags = (scm_t_bits *) SCM_MALLOCDATA (malloc_obj);
+
+ for (i = 0; i != n; ++i)
+ {
+ if (options[i].type == SCM_OPTION_BOOLEAN)
+ flags[i] = 0;
+ else
+ flags[i] = options[i].val;
+ }
+
+ while (!SCM_NULL_OR_NIL_P (args))
+ {
+ SCM name = SCM_CAR (args);
+ int found = 0;
+
+ for (i = 0; i != n && !found; ++i)
+ {
+ if (scm_is_eq (name, SCM_PACK (options[i].name)))
+ {
+ switch (options[i].type)
+ {
+ case SCM_OPTION_BOOLEAN:
+ flags[i] = 1;
+ break;
+ case SCM_OPTION_INTEGER:
+ args = SCM_CDR (args);
+ flags[i] = scm_to_size_t (scm_car (args));
+ break;
+ case SCM_OPTION_SCM:
+ args = SCM_CDR (args);
+ flags[i] = SCM_UNPACK (scm_car (args));
+ break;
+ }
+ found = 1;
+ }
+ }
+
+ if (!found)
+ scm_misc_error (s, "Unknown option name: ~S", scm_list_1 (name));
+
+ args = SCM_CDR (args);
+ }
+
+ for (i = 0; i != n; ++i)
+ {
+ if (options[i].type == SCM_OPTION_SCM)
+ {
+ SCM old = SCM_PACK (options[i].val);
+ SCM new = SCM_PACK (flags[i]);
+ if (!SCM_IMP (old))
+ protected_objects = scm_delq1_x (old, protected_objects);
+ if (!SCM_IMP (new))
+ protected_objects = scm_cons (new, protected_objects);
+ }
+ options[i].val = flags[i];
+ }
+
+ scm_remember_upto_here_2 (locally_protected_args, malloc_obj);
+}
+
+
+SCM
+scm_options (SCM args, scm_t_option options[], unsigned int n, const char *s)
+{
+ if (SCM_UNBNDP (args))
+ return get_option_setting (options, n);
+ else if (!SCM_NULL_OR_NIL_P (args) && !scm_is_pair (args))
+ /* Dirk:FIXME:: This criterion should be improved. IMO it is better to
+ * demand that args is #t if documentation should be shown than to say
+ * that every argument except a list will print out documentation. */
+ return get_documented_option_setting (options, n);
+ else
+ {
+ SCM old_setting;
+ SCM_ASSERT (scm_is_true (scm_list_p (args)), args, 1, s);
+ old_setting = get_option_setting (options, n);
+ change_option_setting (args, options, n, s);
+ return old_setting;
+ }
+}
+
+
+void
+scm_init_opts (SCM (*func) (SCM), scm_t_option options[], unsigned int n)
+{
+ unsigned int i;
+
+ for (i = 0; i != n; ++i)
+ {
+ SCM name = scm_from_locale_symbol (options[i].name);
+ options[i].name = (char *) SCM_UNPACK (name);
+ scm_permanent_object (name);
+ }
+ func (SCM_UNDEFINED);
+}
+
+
+void
+scm_init_options ()
+{
+ scm_gc_register_root (&protected_objects);
+
+#include "libguile/options.x"
+}
+
+/*
+ Local Variables:
+ c-file-style: "gnu"
+ End:
+*/
projects / lilypond.git / blobdiff