1/* variables.c -- How to manipulate user visible variables in Info.
2   $Id: variables.c,v 1.1 2004/10/28 18:14:09 zooey Exp $
3
4   This file is part of GNU Info, a program for reading online documentation
5   stored in Info format.
6
7   Copyright (C) 1993, 97 Free Software Foundation, Inc.
8
9   This program is free software; you can redistribute it and/or modify
10   it under the terms of the GNU General Public License as published by
11   the Free Software Foundation; either version 2, or (at your option)
12   any later version.
13
14   This program is distributed in the hope that it will be useful,
15   but WITHOUT ANY WARRANTY; without even the implied warranty of
16   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
17   GNU General Public License for more details.
18
19   You should have received a copy of the GNU General Public License
20   along with this program; if not, write to the Free Software
21   Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
22
23   Written by Brian Fox (bfox@ai.mit.edu). */
24
25#include "info.h"
26#include "variables.h"
27
28/* **************************************************************** */
29/*                                                                  */
30/*                  User Visible Variables in Info                  */
31/*                                                                  */
32/* **************************************************************** */
33
34/* Choices used by the completer when reading a zero/non-zero value for
35   a variable. */
36static char *on_off_choices[] = { "Off", "On", (char *)NULL };
37
38VARIABLE_ALIST info_variables[] = {
39  { "automatic-footnotes",
40      N_("When \"On\", footnotes appear and disappear automatically"),
41      &auto_footnotes_p, (char **)on_off_choices },
42
43  { "automatic-tiling",
44      N_("When \"On\", creating or deleting a window resizes other windows"),
45      &auto_tiling_p, (char **)on_off_choices },
46
47  { "visible-bell",
48      N_("When \"On\", flash the screen instead of ringing the bell"),
49      &terminal_use_visible_bell_p, (char **)on_off_choices },
50
51  { "errors-ring-bell",
52      N_("When \"On\", errors cause the bell to ring"),
53      &info_error_rings_bell_p, (char **)on_off_choices },
54
55  { "gc-compressed-files",
56      N_("When \"On\", Info garbage collects files which had to be uncompressed"),
57      &gc_compressed_files, (char **)on_off_choices },
58  { "show-index-match",
59      N_("When \"On\", the portion of the matched search string is highlighted"),
60      &show_index_match, (char **)on_off_choices },
61
62  { "scroll-behaviour",
63      N_("Controls what happens when scrolling is requested at the end of a node"),
64      &info_scroll_behaviour, (char **)info_scroll_choices },
65
66  { "scroll-step",
67      N_("The number lines to scroll when the cursor moves out of the window"),
68      &window_scroll_step, (char **)NULL },
69
70  { "ISO-Latin",
71      N_("When \"On\", Info accepts and displays ISO Latin characters"),
72      &ISO_Latin_p, (char **)on_off_choices },
73
74  { (char *)NULL, (char *)NULL, (int *)NULL, (char **)NULL }
75};
76
77DECLARE_INFO_COMMAND (describe_variable, _("Explain the use of a variable"))
78{
79  VARIABLE_ALIST *var;
80  char *description;
81
82  /* Get the variable's name. */
83  var = read_variable_name (_("Describe variable: "), window);
84
85  if (!var)
86    return;
87
88  description = (char *)xmalloc (20 + strlen (var->name)
89				 + strlen (_(var->doc)));
90
91  if (var->choices)
92    sprintf (description, "%s (%s): %s.",
93             var->name, var->choices[*(var->value)], _(var->doc));
94  else
95    sprintf (description, "%s (%d): %s.",
96	     var->name, *(var->value), _(var->doc));
97
98  window_message_in_echo_area ("%s", description);
99  free (description);
100}
101
102DECLARE_INFO_COMMAND (set_variable, _("Set the value of an Info variable"))
103{
104  VARIABLE_ALIST *var;
105  char *line;
106
107  /* Get the variable's name and value. */
108  var = read_variable_name (_("Set variable: "), window);
109
110  if (!var)
111    return;
112
113  /* Read a new value for this variable. */
114  {
115    char prompt[100];
116
117    if (!var->choices)
118      {
119        int potential_value;
120
121        if (info_explicit_arg || count != 1)
122          potential_value = count;
123        else
124          potential_value = *(var->value);
125
126        sprintf (prompt, _("Set %s to value (%d): "),
127                 var->name, potential_value);
128        line = info_read_in_echo_area (active_window, prompt);
129
130        /* If no error was printed, clear the echo area. */
131        if (!info_error_was_printed)
132          window_clear_echo_area ();
133
134        /* User aborted? */
135        if (!line)
136          return;
137
138        /* If the user specified a value, get that, otherwise, we are done. */
139        canonicalize_whitespace (line);
140        if (*line)
141          *(var->value) = atoi (line);
142        else
143          *(var->value) = potential_value;
144
145        free (line);
146      }
147    else
148      {
149        register int i;
150        REFERENCE **array = (REFERENCE **)NULL;
151        int array_index = 0;
152        int array_slots = 0;
153
154        for (i = 0; var->choices[i]; i++)
155          {
156            REFERENCE *entry;
157
158            entry = (REFERENCE *)xmalloc (sizeof (REFERENCE));
159            entry->label = xstrdup (var->choices[i]);
160            entry->nodename = (char *)NULL;
161            entry->filename = (char *)NULL;
162
163            add_pointer_to_array
164              (entry, array_index, array, array_slots, 10, REFERENCE *);
165          }
166
167        sprintf (prompt, _("Set %s to value (%s): "),
168                 var->name, var->choices[*(var->value)]);
169
170        /* Ask the completer to read a variable value for us. */
171        line = info_read_completing_in_echo_area (window, prompt, array);
172
173        info_free_references (array);
174
175        if (!echo_area_is_active)
176          window_clear_echo_area ();
177
178        /* User aborted? */
179        if (!line)
180          {
181            info_abort_key (active_window, 0, 0);
182            return;
183          }
184
185        /* User accepted default choice?  If so, no change. */
186        if (!*line)
187          {
188            free (line);
189            return;
190          }
191
192        /* Find the choice in our list of choices. */
193        for (i = 0; var->choices[i]; i++)
194          if (strcmp (var->choices[i], line) == 0)
195            break;
196
197        if (var->choices[i])
198          *(var->value) = i;
199      }
200  }
201}
202
203/* Read the name of an Info variable in the echo area and return the
204   address of a VARIABLE_ALIST member.  A return value of NULL indicates
205   that no variable could be read. */
206VARIABLE_ALIST *
207read_variable_name (prompt, window)
208     char *prompt;
209     WINDOW *window;
210{
211  register int i;
212  char *line;
213  REFERENCE **variables;
214
215  /* Get the completion array of variable names. */
216  variables = make_variable_completions_array ();
217
218  /* Ask the completer to read a variable for us. */
219  line =
220    info_read_completing_in_echo_area (window, prompt, variables);
221
222  info_free_references (variables);
223
224  if (!echo_area_is_active)
225    window_clear_echo_area ();
226
227  /* User aborted? */
228  if (!line)
229    {
230      info_abort_key (active_window, 0, 0);
231      return ((VARIABLE_ALIST *)NULL);
232    }
233
234  /* User accepted "default"?  (There is none.) */
235  if (!*line)
236    {
237      free (line);
238      return ((VARIABLE_ALIST *)NULL);
239    }
240
241  /* Find the variable in our list of variables. */
242  for (i = 0; info_variables[i].name; i++)
243    if (strcmp (info_variables[i].name, line) == 0)
244      break;
245
246  if (!info_variables[i].name)
247    return ((VARIABLE_ALIST *)NULL);
248  else
249    return (&(info_variables[i]));
250}
251
252/* Make an array of REFERENCE which actually contains the names of the
253   variables available in Info. */
254REFERENCE **
255make_variable_completions_array ()
256{
257  register int i;
258  REFERENCE **array = (REFERENCE **)NULL;
259  int array_index = 0, array_slots = 0;
260
261  for (i = 0; info_variables[i].name; i++)
262    {
263      REFERENCE *entry;
264
265      entry = (REFERENCE *) xmalloc (sizeof (REFERENCE));
266      entry->label = xstrdup (info_variables[i].name);
267      entry->nodename = (char *)NULL;
268      entry->filename = (char *)NULL;
269
270      add_pointer_to_array
271        (entry, array_index, array, array_slots, 200, REFERENCE *);
272    }
273
274  return (array);
275}
276