libguile/options.c

   1 /*      Copyright (C) 1995,1996 Free Software Foundation
   2  *
   3  * This program is free software; you can redistribute it and/or modify
   4  * it under the terms of the GNU General Public License as published by
   5  * the Free Software Foundation; either version 2, or (at your option)
   6  * any later version.
   7  *
   8  * This program 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
  11  * GNU General Public License for more details.
  12  *
  13  * You should have received a copy of the GNU General Public License
  14  * along with this software; see the file COPYING.  If not, write to
  15  * the Free Software Foundation, Inc., 59 Temple Place, Suite 330,
  16  * Boston, MA 02111-1307 USA
  17  *
  18  * As a special exception, the Free Software Foundation gives permission
  19  * for additional uses of the text contained in its release of GUILE.
  20  *
  21  * The exception is that, if you link the GUILE library with other files
  22  * to produce an executable, this does not by itself cause the
  23  * resulting executable to be covered by the GNU General Public License.
  24  * Your use of that executable is in no way restricted on account of
  25  * linking the GUILE library code into it.
  26  *
  27  * This exception does not however invalidate any other reasons why
  28  * the executable file might be covered by the GNU General Public License.
  29  *
  30  * This exception applies only to the code released by the
  31  * Free Software Foundation under the name GUILE.  If you copy
  32  * code from other Free Software Foundation releases into a copy of
  33  * GUILE, as the General Public License permits, the exception does
  34  * not apply to the code that you add in this way.  To avoid misleading
  35  * anyone as to the status of such modified files, you must delete
  36  * this exception notice from them.
  37  *
  38  * If you write modifications of your own for GUILE, it is your choice
  39  * whether to permit this exception to apply to your modifications.
  40  * If you do not wish that, delete this exception notice.
  41  *
  42  * The author can be reached at djurfeldt@nada.kth.se
  43  * Mikael Djurfeldt, SANS/NADA KTH, 10044 STOCKHOLM, SWEDEN */
  44 \f
  45
  46 #include <stdio.h>
  47 #include "_scm.h"
  48
  49 #include "options.h"
  50 \f
  51
  52 /* {Run-time options}
  53  *
  54  * This is the basic interface for low-level configuration of the
  55  * Guile library.  It is used for configuring the reader, evaluator,
  56  * printer and debugger.
  57  *
  58  * Motivation:
  59  *
  60  * 1. Altering option settings can have side effects.
  61  * 2. Option values can be stored in native format.
  62  *    (Important for efficiency in, e. g., the evaluator.)
  63  * 3. Doesn't use up name space.
  64  * 4. Options can be naturally grouped => ease of use.
  65  */
  66
  67 /* scm_options is the core of all options interface procedures.
  68  *
  69  * Some definitions:
  70  *
  71  * Run time options in Guile are arranged in groups.  Each group
  72  * affects a certain aspect of the behaviour of the library.
  73  *
  74  * An "options interface procedure" manages one group of options.  It
  75  * can be used to check or set options, or to get documentation for
  76  * all options of a group.  The options interface procedure is not
  77  * intended to be called directly by the user.  The user should
  78  * instead call
  79  *
  80  *   (<group>-options)
  81  *   (<group>-options 'help)
  82  *   (<group>-options 'full)
  83  *
  84  * to display current option settings (The second version also
  85  * displays documentation.  The third version also displays
  86  * information about programmer's options.), and
  87  *
  88  *   (<group>-enable  '<option-symbol>)
  89  *   (<group>-disable '<option-symbol>)
  90  *   (<group>-set! <option-symbol> <value>)
  91  *   (<group>-options <option setting>)
  92  *
  93  * to alter the state of an option  (The last version sets all
  94  * options according to <option setting>.) where <group> is the name
  95  * of the option group.
  96  *
  97  * An "option setting" represents the state of all low-level options
  98  * managed by one options interface procedure.  It is a list of
  99  * single symbols and symbols followed by a value.
 100  *
 101  * For boolean options, the presence of the symbol of that option in
 102  * the option setting indicates a true value.  If the symbol isn't a
 103  * member of the option setting this represents a false value.
 104  *
 105  * Other options are represented by a symbol followed by the value.
 106  *
 107  * If scm_options is called without arguments, the current option
 108  * setting is returned.  If the argument is an option setting, options
 109  * are altered and the old setting is returned.  If the argument isn't
 110  * a list, a list of sublists is returned, where each sublist contains
 111  * option name, value and documentation string.
 112  */
 113
 114 SCM_SYMBOL (scm_yes_sym, "yes");
 115 SCM_SYMBOL (scm_no_sym, "no");
 116
 117
 118 SCM
 119 scm_options (new_mode, options, n, s)
 120      SCM new_mode;
 121      scm_option options[];
 122      int n;
 123      char *s;
 124 {
 125   int i, docp = (!SCM_UNBNDP (new_mode)
 126                  && !SCM_NULLP (new_mode)
 127                  && (SCM_IMP (new_mode) || SCM_NCONSP (new_mode)));
 128   SCM ans = SCM_EOL, ls;
 129   for (i = 0; i < n; ++i)
 130     {
 131       ls = docp ? scm_cons ((SCM) options[i].doc, SCM_EOL) : ans;
 132       switch (options[i].type)
 133         {
 134         case SCM_OPTION_BOOLEAN:
 135           if (docp)
 136             ls = scm_cons ((int) options[i].val
 137                            ? scm_yes_sym
 138                            : scm_no_sym,
 139                            ls);
 140           break;
 141         case SCM_OPTION_INTEGER:
 142           ls = scm_cons (SCM_MAKINUM ((int) options[i].val), ls);
 143           break;
 144         case SCM_OPTION_SCM:
 145           ls = scm_cons ((SCM) options[i].val, ls);
 146         }
 147       if (!((options[i].type == SCM_OPTION_BOOLEAN)
 148             && !docp
 149             && ! (int) options[i].val))
 150         ls = scm_cons ((SCM) options[i].name, ls);
 151       ans = docp ? scm_cons (ls, ans) : ls;
 152     }
 153   if (!(SCM_UNBNDP (new_mode) || docp))
 154     {
 155       unsigned long *flags;
 156       flags = (unsigned long *) scm_must_malloc (n * sizeof (unsigned long),
 157                                                  "mode buffer");
 158       for (i = 0; i < n; ++i)
 159         if (options[i].type == SCM_OPTION_BOOLEAN)
 160           flags[i] = 0;
 161         else
 162           flags[i] = (unsigned long) options[i].val;
 163       while (SCM_NNULLP (new_mode))
 164         {
 165           SCM_ASSERT (SCM_NIMP (new_mode) && SCM_CONSP (new_mode),
 166                       new_mode,
 167                       SCM_ARG1,
 168                       s);
 169           for (i = 0; i < n; ++i)
 170             if (SCM_CAR (new_mode) == (SCM) options[i].name)
 171               switch (options[i].type)
 172                 {
 173                 case SCM_OPTION_BOOLEAN:
 174                   flags[i] = 1;
 175                   goto cont;
 176                 case SCM_OPTION_INTEGER:
 177                   new_mode = SCM_CDR (new_mode);
 178                   SCM_ASSERT (SCM_NIMP (new_mode)
 179                               && SCM_CONSP (new_mode)
 180                               && SCM_INUMP (SCM_CAR (new_mode)),
 181                               new_mode,
 182                               SCM_ARG1,
 183                               s);
 184                   flags[i] = (unsigned long) SCM_INUM (SCM_CAR (new_mode));
 185                   goto cont;
 186                 case SCM_OPTION_SCM:
 187                   new_mode = SCM_CDR (new_mode);
 188                   flags[i] = SCM_CAR (new_mode);
 189                   goto cont;
 190                 }
 191 #ifndef SCM_RECKLESS
 192           scm_must_free ((char *) flags);
 193           scm_wta (SCM_CAR (new_mode), "Unknown mode flag", s);
 194 #endif
 195         cont:
 196           new_mode = SCM_CDR (new_mode);
 197         }
 198       for (i = 0; i < n; ++i) options[i].val = flags[i];
 199       scm_must_free ((char *) flags);
 200     }
 201   return ans;
 202 }
 203
 204
 205 void
 206 scm_init_opts (func, options, n)
 207      SCM (*func) (SCM);
 208      scm_option options[];
 209      int n;
 210 {
 211   int i;
 212
 213   for (i = 0; i < n; ++i)
 214     {
 215       options[i].name = (char *) SCM_CAR (scm_sysintern0 (options[i].name));
 216       options[i].doc = (char *) scm_permanent_object (scm_take0str
 217                                                       (options[i].doc));
 218     }
 219   func (SCM_UNDEFINED);
 220 }
 221
 222
 223 void
 224 scm_init_options ()
 225 {
 226 #include "options.x"
 227 }