--- a/src/help.cc	Wed Jul 20 18:53:50 1994 +0000
+++ b/src/help.cc	Wed Jul 20 19:19:08 1994 +0000
@@ -25,11 +25,42 @@
 #include "config.h"
 #endif
 
+#include <signal.h>
+#include <stdlib.h>
 #include <iostream.h>
+#include <strstream.h>
 
-#include "builtins.h"
+#include "tree.h"
+#include "sighandlers.h"
+#include "user-prefs.h"
+#include "tree-expr.h"
+#include "variables.h"
+#include "oct-obj.h"
+#include "symtab.h"
+#include "octave.h"
+#include "dirfns.h"
+#include "pager.h"
+#include "error.h"
 #include "utils.h"
 #include "help.h"
+#include "defun.h"
+
+extern "C"
+{
+#include "info/info.h"
+#include "info/dribble.h"
+#include "info/terminal.h"
+
+extern int initialize_info_session ();
+extern int index_entry_exists ();
+extern int do_info_index_search ();
+extern void finish_info_session ();
+extern char *replace_in_documentation ();
+
+// XXX FIXME XXX
+#undef __FUNCTION_DEF
+#include <readline/tilde.h>
+}
 
 static help_list operators[] =
 {
@@ -159,7 +190,7 @@
   { "~=",
     "Logical not equals operator.  See also `<>' and `!='.\n", },
 
-  { (char *) NULL, (char *) NULL, },
+  { 0, 0, },
 };
 
 static help_list keywords[] =
@@ -215,7 +246,7 @@
   { "while",
     "Begin a while loop.\n", },
 
-  { (char *) NULL, (char *) NULL, },
+  { 0, 0, },
 };
 
 /*
@@ -226,26 +257,26 @@
 {
   count = 0;
   help_list *ptr = lst;
-  while (ptr->name != (char *) NULL)
+  while (ptr->name)
     {
       count++;
       ptr++;
     }
 
   if (count == 0)
-    return (char **) NULL;
+    return 0;
     
   char **name_list = new char * [count+1];
 
   ptr = lst;
   int i = 0;
-  while (ptr->name != (char *) NULL)
+  while (ptr->name)
     {
       name_list[i++] = strsave (ptr->name);
       ptr++;
     }
 
-  name_list[i] = (char *) NULL;
+  name_list[i] = 0;
   return name_list;
 }
 
@@ -261,6 +292,267 @@
   return keywords;
 }
 
+static void
+help_syms_list (ostrstream& output_buf, help_list *list,
+		const char *desc)
+{
+  int count = 0;
+  char **symbols = names (list, count);
+  output_buf << "\n*** " << desc << ":\n\n";
+  if (symbols && count > 0)
+    list_in_columns (output_buf, symbols);
+  delete [] symbols;
+}
+
+static void
+simple_help (void)
+{
+  ostrstream output_buf;
+
+  help_syms_list (output_buf, operator_help (), "operators");
+
+  help_syms_list (output_buf, keyword_help (), "reserved words");
+
+  help_syms_list (output_buf, builtin_text_functions_help (),
+		  "text functions (these names are also reserved)");
+
+  help_syms_list (output_buf, builtin_mapper_functions_help (),
+		  "mapper functions");
+
+  help_syms_list (output_buf, builtin_general_functions_help (),
+		  "general functions");
+
+  help_syms_list (output_buf, builtin_variables_help (),
+		  "builtin variables");
+      
+// Also need to list variables and currently compiled functions from
+// the symbol table, if there are any.
+
+// Also need to search octave_path for script files.
+
+  char **path = pathstring_to_vector (user_pref.loadpath);
+
+  char **ptr = path;
+  if (ptr)
+    {
+      while (*ptr)
+	{
+	  int count;
+	  char **names = get_fcn_file_names (count, *ptr, 0);
+	  output_buf << "\n*** function files in "
+		     << make_absolute (*ptr, the_current_working_directory)
+		     << ":\n\n";
+	  if (names && count > 0)
+	    list_in_columns (output_buf, names);
+	  delete [] names;
+	  ptr++;
+	}
+    }
+
+  additional_help_message (output_buf);
+  output_buf << ends;
+  maybe_page_output (output_buf);
+}
+
+static int
+try_info (const char *string, int force = 0)
+{
+  int status = 0;
+
+  char *directory_name = strsave (user_pref.info_file);
+  char *temp = filename_non_directory (directory_name);
+
+  if (temp != directory_name)
+    {
+      *temp = 0;
+      info_add_path (directory_name, INFOPATH_PREPEND);
+    }
+
+  delete [] directory_name;
+
+  NODE *initial_node = info_get_node (user_pref.info_file, 0);
+
+  if (! initial_node)
+    {
+      warning ("can't find info file!\n");
+      status = -1;
+    }
+  else
+    {
+      status = initialize_info_session (initial_node, 0);
+
+      if (status == 0 && (force || index_entry_exists (windows, string)))
+	{
+	  terminal_clear_screen ();
+
+	  terminal_prep_terminal ();
+
+	  display_update_display (windows);
+
+	  info_last_executed_command = 0;
+
+	  if (! force)
+	    do_info_index_search (windows, 0, string);
+
+	  char *format = replace_in_documentation
+	    ("Type \"\\[quit]\" to quit, \"\\[get-help-window]\" for help.");
+
+	  window_message_in_echo_area (format);
+
+	  info_read_and_dispatch ();
+
+	  terminal_goto_xy (0, screenheight - 1);
+
+	  terminal_clear_to_eol ();
+
+	  terminal_unprep_terminal ();
+
+	  status = 1;
+	}
+
+      finish_info_session (initial_node, 0);
+    }
+
+  return status;
+}
+
+DEFUN_TEXT ("help", Fhelp, Shelp, -1, 1,
+  "help [-i] [topic ...]\n\
+\n\
+print cryptic yet witty messages")
+{
+  Octave_object retval;
+
+  DEFINE_ARGV("help");
+
+  if (argc == 1)
+    {
+      simple_help ();
+    }
+  else
+    {
+      if (argv[1] && strcmp (argv[1], "-i") == 0)
+	{
+	  argc--;
+	  argv++;
+
+	  if (argc == 1)
+	    {
+	      volatile sig_handler *old_sigint_handler;
+	      old_sigint_handler = signal (SIGINT, SIG_IGN);
+
+	      try_info (0, 1);
+
+	      signal (SIGINT, old_sigint_handler);
+	    }
+	  else
+	    {
+	      while (--argc > 0)
+		{
+		  argv++;
+
+		  if (! *argv || ! **argv)
+		    continue;
+
+		  volatile sig_handler *old_sigint_handler;
+		  old_sigint_handler = signal (SIGINT, SIG_IGN);
+
+		  if (! try_info (*argv))
+		    {
+		      message ("help",
+			       "sorry, `%s' is not indexed in the manual",
+			       *argv); 
+		      sleep (2);
+		    }
+
+		  signal (SIGINT, old_sigint_handler);
+		}
+	    }
+	}
+      else
+	{
+	  ostrstream output_buf;
+
+	  char *fcn_file_name = 0;
+	  symbol_record *sym_rec;
+	  help_list *op_help_list = operator_help ();
+	  help_list *kw_help_list = keyword_help ();
+
+	  while (--argc > 0)
+	    {
+	      argv++;
+
+	      if (! *argv || ! **argv)
+		continue;
+
+	      if (help_from_list (output_buf, op_help_list, *argv, 0))
+		continue;
+
+	      if (help_from_list (output_buf, kw_help_list, *argv, 0))
+		continue;
+
+	      sym_rec = curr_sym_tab->lookup (*argv, 0, 0);
+	      if (sym_rec)
+		{
+		  char *h = sym_rec->help ();
+		  if (h && *h)
+		    {
+		      output_buf << "\n*** " << *argv << ":\n\n"
+				 << h << "\n";
+		      continue;
+		    }
+		}
+
+	      sym_rec = global_sym_tab->lookup (*argv, 0, 0);
+	      if (sym_rec && ! symbol_out_of_date (sym_rec))
+		{
+		  char *h = sym_rec->help ();
+		  if (h && *h)
+		    {
+		      output_buf << "\n*** " << *argv << ":\n\n"
+				 << h << "\n";
+		      continue;
+		    }
+		}
+
+// Try harder to find function files that might not be defined yet, or
+// that appear to be out of date.  Don\'t execute commands from the
+// file if it turns out to be a script file.
+
+	      fcn_file_name = fcn_file_in_path (*argv);
+	      if (fcn_file_name)
+		{
+		  sym_rec = global_sym_tab->lookup (*argv, 1, 0);
+		  if (sym_rec)
+		    {
+		      tree_identifier tmp (sym_rec);
+		      tmp.parse_fcn_file (0);
+		      char *h = sym_rec->help ();
+		      if (h && *h)
+			{
+			  output_buf << "\n*** " << *argv << ":\n\n"
+				     << h << "\n"; 
+			  continue;
+			}
+		    }
+		}
+	      delete [] fcn_file_name;
+
+	      output_buf << "\nhelp: sorry, `" << *argv
+			 << "' is not documented\n"; 
+	    }
+
+	  additional_help_message (output_buf);
+	  output_buf << ends;
+	  maybe_page_output (output_buf);
+	}
+    }
+
+  DELETE_ARGV;
+
+  return retval;
+}
+
 /*
 ;;; Local Variables: ***
 ;;; mode: C++ ***