--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/info/variables.c	Thu Oct 21 22:39:46 1993 +0000
@@ -0,0 +1,272 @@
+/* variables.c -- How to manipulate user visible variables in Info. */
+
+/* This file is part of GNU Info, a program for reading online documentation
+   stored in Info format.
+
+   Copyright (C) 1993 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 program; if not, write to the Free Software
+   Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
+
+   Written by Brian Fox (bfox@ai.mit.edu). */
+
+#include "info.h"
+#include "variables.h"
+
+/* **************************************************************** */
+/*								    */
+/*		    User Visible Variables in Info		    */
+/*								    */
+/* **************************************************************** */
+
+/* Choices used by the completer when reading a zero/non-zero value for
+   a variable. */
+static char *on_off_choices[] = { "Off", "On", (char *)NULL };
+
+VARIABLE_ALIST info_variables[] = {
+  { "automatic-footnotes",
+      "When \"On\", footnotes appear and disappear automatically",
+      &auto_footnotes_p, (char **)on_off_choices },
+
+  { "automatic-tiling",
+      "When \"On\", creating or deleting a window resizes other windows",
+      &auto_tiling_p, (char **)on_off_choices },
+
+  { "visible-bell",
+      "When \"On\", flash the screen instead of ringing the bell",
+      &terminal_use_visible_bell_p, (char **)on_off_choices },
+
+  { "errors-ring-bell",
+      "When \"On\", errors cause the bell to ring",
+      &info_error_rings_bell_p, (char **)on_off_choices },
+
+  { "gc-compressed-files",
+      "When \"On\", Info garbage collects files which had to be uncompressed",
+      &gc_compressed_files, (char **)on_off_choices },
+  { "show-index-match",
+      "When \"On\", the portion of the matched search string is highlighted",
+      &show_index_match, (char **)on_off_choices },
+
+  { "scroll-behaviour",
+      "Controls what happens when scrolling is requested at the end of a node",
+      &info_scroll_behaviour, (char **)info_scroll_choices },
+
+  { "scroll-step",
+      "The number lines to scroll when the cursor moves out of the window",
+      &window_scroll_step, (char **)NULL },
+
+  { "ISO-Latin",
+      "When \"On\", Info accepts and displays ISO Latin characters",
+      &ISO_Latin_p, (char **)on_off_choices },
+
+  { (char *)NULL, (char *)NULL, (int *)NULL, (char **)NULL }
+};
+
+DECLARE_INFO_COMMAND (describe_variable, "Explain the use of a variable")
+{
+  VARIABLE_ALIST *var;
+  char *description;
+
+  /* Get the variable's name. */
+  var = read_variable_name ("Describe variable: ", window);
+
+  if (!var)
+    return;
+
+  description = (char *)xmalloc (20 + strlen (var->name) + strlen (var->doc));
+
+  if (var->choices)
+    sprintf (description, "%s (%s): %s.",
+	     var->name, var->choices[*(var->value)], var->doc);
+  else
+    sprintf (description, "%s (%d): %s.", var->name, *(var->value), var->doc);
+
+  window_message_in_echo_area ("%s", description);
+  free (description);
+}
+
+DECLARE_INFO_COMMAND (set_variable, "Set the value of an Info variable")
+{
+  VARIABLE_ALIST *var;
+  char *line;
+
+  /* Get the variable's name and value. */
+  var = read_variable_name ("Set variable: ", window);
+
+  if (!var)
+    return;
+
+  /* Read a new value for this variable. */
+  {
+    char prompt[100];
+
+    if (!var->choices)
+      {
+	int potential_value;
+
+	if (info_explicit_arg || count != 1)
+	  potential_value = count;
+	else
+	  potential_value = *(var->value);
+
+	sprintf (prompt, "Set %s to value (%d): ",
+		 var->name, potential_value);
+	line = info_read_in_echo_area (active_window, prompt);
+
+	/* If no error was printed, clear the echo area. */
+	if (!info_error_was_printed)
+	  window_clear_echo_area ();
+
+	/* User aborted? */
+	if (!line)
+	  return;
+
+	/* If the user specified a value, get that, otherwise, we are done. */
+	canonicalize_whitespace (line);
+	if (*line)
+	  *(var->value) = atoi (line);
+	else
+	  *(var->value) = potential_value;
+
+	free (line);
+      }
+    else
+      {
+	register int i;
+	REFERENCE **array = (REFERENCE **)NULL;
+	int array_index = 0;
+	int array_slots = 0;
+
+	for (i = 0; var->choices[i]; i++)
+	  {
+	    REFERENCE *entry;
+
+	    entry = (REFERENCE *)xmalloc (sizeof (REFERENCE));
+	    entry->label = savestring (var->choices[i]);
+	    entry->nodename = (char *)NULL;
+	    entry->filename = (char *)NULL;
+
+	    add_pointer_to_array
+	      (entry, array_index, array, array_slots, 10, REFERENCE *);
+	  }
+
+	sprintf (prompt, "Set %s to value (%s): ",
+		 var->name, var->choices[*(var->value)]);
+
+	/* Ask the completer to read a variable value for us. */
+	line = info_read_completing_in_echo_area (window, prompt, array);
+
+	info_free_references (array);
+
+	if (!echo_area_is_active)
+	  window_clear_echo_area ();
+
+	/* User aborted? */
+	if (!line)
+	  {
+	    info_abort_key (active_window, 0, 0);
+	    return;
+	  }
+
+	/* User accepted default choice?  If so, no change. */
+	if (!*line)
+	  {
+	    free (line);
+	    return;
+	  }
+
+	/* Find the choice in our list of choices. */
+	for (i = 0; var->choices[i]; i++)
+	  if (strcmp (var->choices[i], line) == 0)
+	    break;
+
+	if (var->choices[i])
+	  *(var->value) = i;
+      }
+  }
+}
+
+/* Read the name of an Info variable in the echo area and return the
+   address of a VARIABLE_ALIST member.  A return value of NULL indicates
+   that no variable could be read. */
+VARIABLE_ALIST *
+read_variable_name (prompt, window)
+     char *prompt;
+     WINDOW *window;
+{
+  register int i;
+  char *line;
+  REFERENCE **variables;
+
+  /* Get the completion array of variable names. */
+  variables = make_variable_completions_array ();
+
+  /* Ask the completer to read a variable for us. */
+  line =
+    info_read_completing_in_echo_area (window, prompt, variables);
+
+  info_free_references (variables);
+
+  if (!echo_area_is_active)
+    window_clear_echo_area ();
+
+  /* User aborted? */
+  if (!line)
+    {
+      info_abort_key (active_window, 0, 0);
+      return ((VARIABLE_ALIST *)NULL);
+    }
+
+  /* User accepted "default"?  (There is none.) */
+  if (!*line)
+    {
+      free (line);
+      return ((VARIABLE_ALIST *)NULL);
+    }
+
+  /* Find the variable in our list of variables. */
+  for (i = 0; info_variables[i].name; i++)
+    if (strcmp (info_variables[i].name, line) == 0)
+      break;
+
+  if (!info_variables[i].name)
+    return ((VARIABLE_ALIST *)NULL);
+  else
+    return (&(info_variables[i]));
+}
+
+/* Make an array of REFERENCE which actually contains the names of the
+   variables available in Info. */
+REFERENCE **
+make_variable_completions_array ()
+{
+  register int i;
+  REFERENCE **array = (REFERENCE **)NULL;
+  int array_index = 0, array_slots = 0;
+
+  for (i = 0; info_variables[i].name; i++)
+    {
+      REFERENCE *entry;
+
+      entry = (REFERENCE *)xmalloc (sizeof (REFERENCE));
+      entry->label = savestring (info_variables[i].name);
+      entry->nodename = (char *)NULL;
+      entry->filename = (char *)NULL;
+
+      add_pointer_to_array
+	(entry, array_index, array, array_slots, 200, REFERENCE *);
+    }
+
+  return (array);
+}