1 /* Copyright (C) 1995,1996,1998,2000,2001, 2006, 2008 Free Software Foundation
3 * This library is free software; you can redistribute it and/or
4 * modify it under the terms of the GNU Lesser General Public
5 * License as published by the Free Software Foundation; either
6 * version 2.1 of the License, or (at your option) any later version.
8 * This library is distributed in the hope that it will be useful,
9 * but WITHOUT ANY WARRANTY; without even the implied warranty of
10 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
11 * Lesser General Public License for more details.
13 * You should have received a copy of the GNU Lesser General Public
14 * License along with this library; if not, write to the Free Software
15 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
23 #include "libguile/_scm.h"
24 #include "libguile/mallocs.h"
25 #include "libguile/strings.h"
26 #include "libguile/lang.h"
28 #include "libguile/options.h"
33 * This is the basic interface for low-level configuration of the
34 * Guile library. It is used for configuring the reader, evaluator,
35 * printer and debugger.
39 * 1. Altering option settings can have side effects.
40 * 2. Option values can be stored in native format.
41 * (Important for efficiency in, e. g., the evaluator.)
42 * 3. Doesn't use up name space.
43 * 4. Options can be naturally grouped => ease of use.
46 /* scm_options is the core of all options interface procedures.
50 * Run time options in Guile are arranged in groups. Each group
51 * affects a certain aspect of the behaviour of the library.
53 * An "options interface procedure" manages one group of options. It
54 * can be used to check or set options, or to get documentation for
55 * all options of a group. The options interface procedure is not
56 * intended to be called directly by the user. The user should
60 * (<group>-options 'help)
61 * (<group>-options 'full)
63 * to display current option settings (The second version also
64 * displays documentation. The third version also displays
65 * information about programmer's options.), and
67 * (<group>-enable '<option-symbol>)
68 * (<group>-disable '<option-symbol>)
69 * (<group>-set! <option-symbol> <value>)
70 * (<group>-options <option setting>)
72 * to alter the state of an option (The last version sets all
73 * options according to <option setting>.) where <group> is the name
74 * of the option group.
76 * An "option setting" represents the state of all low-level options
77 * managed by one options interface procedure. It is a list of
78 * single symbols and symbols followed by a value.
80 * For boolean options, the presence of the symbol of that option in
81 * the option setting indicates a true value. If the symbol isn't a
82 * member of the option setting this represents a false value.
84 * Other options are represented by a symbol followed by the value.
86 * If scm_options is called without arguments, the current option
87 * setting is returned. If the argument is an option setting, options
88 * are altered and the old setting is returned. If the argument isn't
89 * a list, a list of sublists is returned, where each sublist contains
90 * option name, value and documentation string.
93 SCM_SYMBOL (scm_yes_sym, "yes");
94 SCM_SYMBOL (scm_no_sym, "no");
96 static SCM protected_objects = SCM_EOL;
98 /* Return a list of the current option setting. The format of an
99 * option setting is described in the above documentation. */
101 get_option_setting (const scm_t_option options[], unsigned int n)
105 for (i = 0; i != n; ++i)
107 switch (options[i].type)
109 case SCM_OPTION_BOOLEAN:
111 ls = scm_cons (SCM_PACK (options[i].name), ls);
113 case SCM_OPTION_INTEGER:
114 ls = scm_cons (scm_from_unsigned_integer (options[i].val), ls);
115 ls = scm_cons (SCM_PACK (options[i].name), ls);
118 ls = scm_cons (SCM_PACK (options[i].val), ls);
119 ls = scm_cons (SCM_PACK (options[i].name), ls);
126 /* Return a list of sublists, where each sublist contains option name, value
127 * and documentation string. */
129 get_documented_option_setting (const scm_t_option options[], unsigned int n)
134 for (i = 0; i != n; ++i)
136 SCM ls = scm_cons (scm_from_locale_string (options[i].doc), SCM_EOL);
137 switch (options[i].type)
139 case SCM_OPTION_BOOLEAN:
140 ls = scm_cons (options[i].val ? scm_yes_sym : scm_no_sym, ls);
142 case SCM_OPTION_INTEGER:
143 ls = scm_cons (scm_from_unsigned_integer (options[i].val), ls);
146 ls = scm_cons (SCM_PACK (options[i].val), ls);
148 ls = scm_cons (SCM_PACK (options[i].name), ls);
149 ans = scm_cons (ls, ans);
155 /* Alters options according to the given option setting 'args'. The value of
156 * args is known to be a list, but it is not known whether the list is a well
157 * formed option setting, i. e. if for every non-boolean option a value is
158 * given. For this reason, the function applies all changes to a copy of the
159 * original setting in memory. Only if 'args' was successfully processed,
160 * the new setting will overwrite the old one. */
162 change_option_setting (SCM args, scm_t_option options[], unsigned int n, const char *s)
165 SCM locally_protected_args = args;
166 SCM malloc_obj = scm_malloc_obj (n * sizeof (scm_t_bits));
167 scm_t_bits *flags = (scm_t_bits *) SCM_MALLOCDATA (malloc_obj);
169 for (i = 0; i != n; ++i)
171 if (options[i].type == SCM_OPTION_BOOLEAN)
174 flags[i] = options[i].val;
177 while (!SCM_NULL_OR_NIL_P (args))
179 SCM name = SCM_CAR (args);
182 for (i = 0; i != n && !found; ++i)
184 if (scm_is_eq (name, SCM_PACK (options[i].name)))
186 switch (options[i].type)
188 case SCM_OPTION_BOOLEAN:
191 case SCM_OPTION_INTEGER:
192 args = SCM_CDR (args);
193 flags[i] = scm_to_size_t (scm_car (args));
196 args = SCM_CDR (args);
197 flags[i] = SCM_UNPACK (scm_car (args));
205 scm_misc_error (s, "Unknown option name: ~S", scm_list_1 (name));
207 args = SCM_CDR (args);
210 for (i = 0; i != n; ++i)
212 if (options[i].type == SCM_OPTION_SCM)
214 SCM old = SCM_PACK (options[i].val);
215 SCM new = SCM_PACK (flags[i]);
217 protected_objects = scm_delq1_x (old, protected_objects);
219 protected_objects = scm_cons (new, protected_objects);
221 options[i].val = flags[i];
224 scm_remember_upto_here_2 (locally_protected_args, malloc_obj);
229 scm_options (SCM args, scm_t_option options[], unsigned int n, const char *s)
231 if (SCM_UNBNDP (args))
232 return get_option_setting (options, n);
233 else if (!SCM_NULL_OR_NIL_P (args) && !scm_is_pair (args))
234 /* Dirk:FIXME:: This criterion should be improved. IMO it is better to
235 * demand that args is #t if documentation should be shown than to say
236 * that every argument except a list will print out documentation. */
237 return get_documented_option_setting (options, n);
241 SCM_ASSERT (scm_is_true (scm_list_p (args)), args, 1, s);
242 old_setting = get_option_setting (options, n);
243 change_option_setting (args, options, n, s);
250 scm_init_opts (SCM (*func) (SCM), scm_t_option options[], unsigned int n)
254 for (i = 0; i != n; ++i)
256 SCM name = scm_from_locale_symbol (options[i].name);
257 options[i].name = (char *) SCM_UNPACK (name);
258 scm_permanent_object (name);
260 func (SCM_UNDEFINED);
267 scm_gc_register_root (&protected_objects);
269 #include "libguile/options.x"