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/*

Copyright (C) 1993-2012 John W. Eaton

This file is part of Octave.

Octave 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 3 of the License, or (at your
option) any later version.

Octave 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 Octave; see the file COPYING.  If not, see
<http://www.gnu.org/licenses/>.

*/

#ifdef HAVE_CONFIG_H
#include <config.h>
#endif

#include <cstdlib>
#include <cstring>

#include <algorithm>
#include <iostream>
#include <fstream>
#include <sstream>
#include <string>

#include <sys/types.h>
#include <unistd.h>

#include "cmd-edit.h"
#include "file-ops.h"
#include "file-stat.h"
#include "oct-env.h"
#include "str-vec.h"

#include <defaults.h>
#include "defun.h"
#include "dirfns.h"
#include "error.h"
#include "gripes.h"
#include "help.h"
#include "input.h"
#include "load-path.h"
#include "oct-obj.h"
#include "ov-usr-fcn.h"
#include "pager.h"
#include "parse.h"
#include "pathsearch.h"
#include "procstream.h"
#include "pt-pr-code.h"
#include "sighandlers.h"
#include "symtab.h"
#include "syswait.h"
#include "toplev.h"
#include "unwind-prot.h"
#include "utils.h"
#include "variables.h"
#include "version.h"
#include "quit.h"

// Name of the doc cache file specified on the command line.
// (--doc-cache-file file)
std::string Vdoc_cache_file;

// Name of the info file specified on command line.
// (--info-file file)
std::string Vinfo_file;

// Name of the info reader we'd like to use.
// (--info-program program)
std::string Vinfo_program;

// Name of the makeinfo program to run.
static std::string Vmakeinfo_program = "makeinfo";

// If TRUE, don't print additional help message in help and usage
// functions.
static bool Vsuppress_verbose_help_message = false;

#include <map>

typedef std::map<std::string, std::string> map_type;
typedef map_type::value_type pair_type;
typedef map_type::const_iterator map_iter;

template<typename T, std::size_t z>
std::size_t
size (T const (&)[z])
{
  return z;
}

const static pair_type operators[] =
{
  pair_type ("!",
    "-*- texinfo -*-\n\
@deftypefn {Operator} {} !\n\
Logical 'not' operator.\n\
@seealso{~, not}\n\
@end deftypefn"),

  pair_type ("~",
    "-*- texinfo -*-\n\
@deftypefn {Operator} {} ~\n\
Logical 'not' operator.\n\
@seealso{!, not}\n\
@end deftypefn"),

  pair_type ("!=",
    "-*- texinfo -*-\n\
@deftypefn {Operator} {} !=\n\
Logical 'not equals' operator.\n\
@seealso{~=, ne}\n\
@end deftypefn"),

  pair_type ("~=",
    "-*- texinfo -*-\n\
@deftypefn {Operator} {} ~=\n\
Logical 'not equals' operator.\n\
@seealso{!=, ne}\n\
@end deftypefn"),

  pair_type ("\"",
    "-*- texinfo -*-\n\
@deftypefn {Operator} {} \"\n\
String delimiter.\n\
@end deftypefn"),

  pair_type ("#",
    "-*- texinfo -*-\n\
@deftypefn {Operator} {} #\n\
Begin comment character.\n\
@seealso{%, #@{}\n\
@end deftypefn"),

  pair_type ("%",
    "-*- texinfo -*-\n\
@deftypefn {Operator} {} %\n\
Begin comment character.\n\
@seealso{#, %@{}\n\
@end deftypefn"),

  pair_type ("#{",
    "-*- texinfo -*-\n\
@deftypefn {Operator} {} #@{\n\
Begin block comment.  There must be nothing else, other than\n\
whitespace, in the line both before and after @code{#@{}.\n\
It is possible to nest block comments.\n\
@seealso{%@{, #@}, #}\n\
@end deftypefn"),

  pair_type ("%{",
    "-*- texinfo -*-\n\
@deftypefn {Operator} {} %@{\n\
Begin block comment.  There must be nothing else, other than\n\
whitespace, in the line both before and after @code{%@{}.\n\
It is possible to nest block comments.\n\
@seealso{#@{, %@}, %}\n\
@end deftypefn"),

  pair_type ("#}",
    "-*- texinfo -*-\n\
@deftypefn {Operator} {} #@}\n\
Close block comment.  There must be nothing else, other than\n\
whitespace, in the line both before and after @code{#@}}.\n\
It is possible to nest block comments.\n\
@seealso{%@}, #@{, #}\n\
@end deftypefn"),

  pair_type ("%}",
    "-*- texinfo -*-\n\
@deftypefn {Operator} {} %@}\n\
Close block comment.  There must be nothing else, other than\n\
whitespace, in the line both before and after @code{%@}}.\n\
It is possible to nest block comments.\n\
@seealso{#@}, %@{, %}\n\
@end deftypefn"),

  pair_type ("...",
    "-*- texinfo -*-\n\
@deftypefn {Operator} {} ...\n\
Continuation marker.  Joins current line with following line.\n\
@end deftypefn"),

  pair_type ("&",
    "-*- texinfo -*-\n\
@deftypefn {Operator} {} &\n\
Element by element logical 'and' operator.\n\
@seealso{&&, and}\n\
@end deftypefn"),

  pair_type ("&&",
    "-*- texinfo -*-\n\
@deftypefn {Operator} {} &&\n\
Logical 'and' operator (with short-circuit evaluation).\n\
@seealso{&, and}\n\
@end deftypefn"),

  pair_type ("'",
    "-*- texinfo -*-\n\
@deftypefn {Operator} {} '\n\
Matrix transpose operator.  For complex matrices, computes the\n\
complex conjugate (Hermitian) transpose.\n\
\n\
The single quote character may also be used to delimit strings, but\n\
it is better to use the double quote character, since that is never\n\
ambiguous.\n\
@seealso{.', transpose}\n\
@end deftypefn"),

  pair_type ("(",
    "-*- texinfo -*-\n\
@deftypefn {Operator} {} (\n\
Array index or function argument delimiter.\n\
@end deftypefn"),

  pair_type (")",
    "-*- texinfo -*-\n\
@deftypefn {Operator} {} )\n\
Array index or function argument delimiter.\n\
@end deftypefn"),

  pair_type ("*",
    "-*- texinfo -*-\n\
@deftypefn {Operator} {} *\n\
Multiplication operator.\n\
@seealso{.*, times}\n\
@end deftypefn"),

  pair_type ("**",
    "-*- texinfo -*-\n\
@deftypefn {Operator} {} **\n\
Power operator.  This may return complex results for real inputs.  Use\n\
@code{realsqrt}, @code{cbrt}, @code{nthroot}, or @code{realroot} to obtain\n\
real results when possible.\n\
@seealso{power, ^, .**, .^, realpow, realsqrt, cbrt, nthroot}\n\
@end deftypefn"),

  pair_type ("^",
    "-*- texinfo -*-\n\
@deftypefn {Operator} {} ^\n\
Power operator.  This may return complex results for real inputs.  Use\n\
@code{realsqrt}, @code{cbrt}, @code{nthroot}, or @code{realroot} to obtain\n\
real results when possible.\n\
@seealso{power, **, .^, .**, realpow, realsqrt, cbrt, nthroot}\n\
@end deftypefn"),

  pair_type ("+",
    "-*- texinfo -*-\n\
@deftypefn {Operator} {} +\n\
Addition operator.\n\
@seealso{plus}\n\
@end deftypefn"),

  pair_type ("++",
    "-*- texinfo -*-\n\
@deftypefn {Operator} {} ++\n\
Increment operator.  As in C, may be applied as a prefix or postfix\n\
operator.\n\
@seealso{--}\n\
@end deftypefn"),

  pair_type (",",
    "-*- texinfo -*-\n\
@deftypefn {Operator} {} ,\n\
Array index, function argument, or command separator.\n\
@end deftypefn"),

  pair_type ("-",
    "-*- texinfo -*-\n\
@deftypefn {Operator} {} -\n\
Subtraction or unary negation operator.\n\
@seealso{minus}\n\
@end deftypefn"),

  pair_type ("--",
    "-*- texinfo -*-\n\
@deftypefn {Operator} {} --\n\
Decrement operator.  As in C, may be applied as a prefix or postfix\n\
operator.\n\
@seealso{++}\n\
@end deftypefn"),

  pair_type (".'",
    "-*- texinfo -*-\n\
@deftypefn {Operator} {} .'\n\
Matrix transpose operator.  For complex matrices, computes the\n\
transpose, @emph{not} the complex conjugate transpose.\n\
@seealso{', transpose}\n\
@end deftypefn"),

  pair_type (".*",
    "-*- texinfo -*-\n\
@deftypefn {Operator} {} .*\n\
Element by element multiplication operator.\n\
@seealso{*, times}\n\
@end deftypefn"),

  pair_type (".**",
    "-*- texinfo -*-\n\
@deftypefn {Operator} {} .*\n\
Element by element power operator.  If several complex results are possible,\n\
returns the one with smallest non-negative argument (angle).  Use\n\
@code{realpow}, @code{realsqrt}, @code{cbrt}, or @code{nthroot} if a\n\
real result is preferred.\n\
@seealso{**, ^, .^, power, realpow, realsqrt, cbrt, nthroot}\n\
@end deftypefn"),

  pair_type (".^",
    "-*- texinfo -*-\n\
@deftypefn {Operator} {} .^\n\
Element by element power operator.  If several complex results are possible,\n\
returns the one with smallest non-negative argument (angle).  Use\n\
@code{realpow}, @code{realsqrt}, @code{cbrt}, or @code{nthroot} if a\n\
real result is preferred.\n\
@seealso{.**, ^, **, power, realpow, realsqrt, cbrt, nthroot}\n\
@end deftypefn"),

  pair_type ("./",
    "-*- texinfo -*-\n\
@deftypefn {Operator} {} ./\n\
Element by element right division operator.\n\
@seealso{/, .\\, rdivide, mrdivide}\n\
@end deftypefn"),

  pair_type ("/",
    "-*- texinfo -*-\n\
@deftypefn {Operator} {} /\n\
Right division operator.\n\
@seealso{./, \\, rdivide, mrdivide}\n\
@end deftypefn"),

  pair_type (".\\",
    "-*- texinfo -*-\n\
@deftypefn {Operator} {} .\\\n\
Element by element left division operator.\n\
@seealso{\\, ./, rdivide, mrdivide}\n\
@end deftypefn"),

  pair_type ("\\",
    "-*- texinfo -*-\n\
@deftypefn {Operator} {} \\\n\
Left division operator.\n\
@seealso{.\\, /, ldivide, mldivide}\n\
@end deftypefn"),

  pair_type (":",
    "-*- texinfo -*-\n\
@deftypefn {Operator} {} :\n\
Select entire rows or columns of matrices.\n\
@end deftypefn"),

  pair_type (";",
    "-*- texinfo -*-\n\
@deftypefn {Operator} {} ;\n\
Array row or command separator.\n\
@seealso{,}\n\
@end deftypefn"),

  pair_type ("<",
    "-*- texinfo -*-\n\
@deftypefn {Operator} {} <\n\
'Less than' operator.\n\
@seealso{lt}\n\
@end deftypefn"),

  pair_type ("<=",
    "-*- texinfo -*-\n\
@deftypefn {Operator} {} <=\n\
'Less than' or 'equals' operator.\n\
@seealso{le}\n\
@end deftypefn"),

  pair_type ("=",
    "-*- texinfo -*-\n\
@deftypefn {Operator} {} =\n\
Assignment operator.\n\
@end deftypefn"),

  pair_type ("==",
    "-*- texinfo -*-\n\
@deftypefn {Operator} {} ==\n\
Equality test operator.\n\
@seealso{eq}\n\
@end deftypefn"),

  pair_type (">",
    "-*- texinfo -*-\n\
@deftypefn {Operator} {} >\n\
'Greater than' operator.\n\
@seealso{gt}\n\
@end deftypefn"),

  pair_type (">=",
    "-*- texinfo -*-\n\
@deftypefn {Operator} {} >=\n\
'Greater than' or 'equals' operator.\n\
@seealso{ge}\n\
@end deftypefn"),

  pair_type ("[",
    "-*- texinfo -*-\n\
@deftypefn {Operator} {} [\n\
Return list delimiter.\n\
@seealso{]}\n\
@end deftypefn"),

  pair_type ("]",
    "-*- texinfo -*-\n\
@deftypefn {Operator} {} ]\n\
Return list delimiter.\n\
@seealso{[}\n\
@end deftypefn"),

  pair_type ("|",
    "-*- texinfo -*-\n\
@deftypefn {Operator} {} |\n\
Element by element logical 'or' operator.\n\
@seealso{||, or}\n\
@end deftypefn"),

  pair_type ("||",
    "-*- texinfo -*-\n\
@deftypefn {Operator} {} ||\n\
Logical 'or' (with short-circuit evaluation) operator.\n\
@seealso{|, or}\n\
@end deftypefn"),
};

const static pair_type keywords[] =
{
  pair_type ("break",
    "-*- texinfo -*-\n\
@deftypefn {Keyword} {} break\n\
Exit the innermost enclosing do, while or for loop.\n\
@seealso{do, while, for, parfor, continue}\n\
@end deftypefn"),

  pair_type ("case",
    "-*- texinfo -*-\n\
@deftypefn {Keyword} {} case @{@var{value}@}\n\
A case statement in an switch.  Octave cases are exclusive and do not\n\
fall-through as do C-language cases.  A switch statement must have at least\n\
one case.  See @code{switch} for an example.\n\
@seealso{switch}\n\
@end deftypefn"),

  pair_type ("catch",
    "-*- texinfo -*-\n\
@deftypefn {Keyword} {} catch\n\
Begin the cleanup part of a try-catch block.\n\
@seealso{try}\n\
@end deftypefn"),

  pair_type ("continue",
    "-*- texinfo -*-\n\
@deftypefn {Keyword} {} continue\n\
Jump to the end of the innermost enclosing do, while or for loop.\n\
@seealso{do, while, for, parfor, break}\n\
@end deftypefn"),

  pair_type ("do",
    "-*- texinfo -*-\n\
@deftypefn {Keyword} {} do\n\
Begin a do-until loop.  This differs from a do-while loop in that the\n\
body of the loop is executed at least once.\n\
@seealso{while}\n\
@end deftypefn"),

  pair_type ("else",
    "-*- texinfo -*-\n\
@deftypefn {Keyword} {} else\n\
Alternate action for an if block.  See @code{if} for an example.\n\
@seealso{if}\n\
@end deftypefn"),

  pair_type ("elseif",
    "-*- texinfo -*-\n\
@deftypefn {Keyword} {} elseif (@var{condition})\n\
Alternate conditional test for an if block.  See @code{if} for an example.\n\
@seealso{if}\n\
@end deftypefn"),

  pair_type ("end",
    "-*- texinfo -*-\n\
@deftypefn {Keyword} {} end\n\
Mark the end of any @code{for}, @code{if}, @code{do}, @code{while}, or\n\
@code{function} block.\n\
@seealso{for, parfor, if, do, while, function}\n\
@end deftypefn"),

  pair_type ("end_try_catch",
    "-*- texinfo -*-\n\
@deftypefn {Keyword} {} end_try_catch\n\
Mark the end of an @code{try-catch} block.\n\
@seealso{try, catch}\n\
@end deftypefn"),

  pair_type ("end_unwind_protect",
    "-*- texinfo -*-\n\
@deftypefn {Keyword} {} end_unwind_protect\n\
Mark the end of an unwind_protect block.\n\
@seealso{unwind_protect}\n\
@end deftypefn"),

  pair_type ("endfor",
    "-*- texinfo -*-\n\
@deftypefn {Keyword} {} endfor\n\
Mark the end of a for loop.  See @code{for} for an example.\n\
@seealso{for}\n\
@end deftypefn"),

  pair_type ("endfunction",
    "-*- texinfo -*-\n\
@deftypefn {Keyword} {} endfunction\n\
Mark the end of a function.\n\
@seealso{function}\n\
@end deftypefn"),

  pair_type ("endif",
    "-*- texinfo -*-\n\
@deftypefn {Keyword} {} endif\n\
Mark the end of an if block.  See @code{if} for an example.\n\
@seealso{if}\n\
@end deftypefn"),

  pair_type ("endparfor",
    "-*- texinfo -*-\n\
@deftypefn {Keyword} {} endparfor\n\
Mark the end of a parfor loop.  See @code{parfor} for an example.\n\
@seealso{parfor}\n\
@end deftypefn"),

  pair_type ("endswitch",
    "-*- texinfo -*-\n\
@deftypefn {Keyword} {} endswitch\n\
Mark the end of a switch block.  See @code{switch} for an example.\n\
@seealso{switch}\n\
@end deftypefn"),

  pair_type ("endwhile",
    "-*- texinfo -*-\n\
@deftypefn {Keyword} {} endwhile\n\
Mark the end of a while loop.  See @code{while} for an example.\n\
@seealso{do, while}\n\
@end deftypefn"),

  pair_type ("for",
    "-*- texinfo -*-\n\
@deftypefn {Keyword} {} for @var{i} = @var{range}\n\
Begin a for loop.\n\
\n\
@example\n\
@group\n\
for i = 1:10\n\
  i\n\
endfor\n\
@end group\n\
@end example\n\
@seealso{do, parfor, while}\n\
@end deftypefn"),

  pair_type ("function",
    "-*- texinfo -*-\n\
@deftypefn  {Keyword} {} function @var{outputs} = function (@var{input}, @dots{})\n\
@deftypefnx {Keyword} {} function {} function (@var{input}, @dots{})\n\
@deftypefnx {Keyword} {} function @var{outputs} = function\n\
Begin a function body with @var{outputs} as results and @var{inputs} as\n\
parameters.\n\
@seealso{return}\n\
@end deftypefn"),

  pair_type ("global",
    "-*- texinfo -*-\n\
@deftypefn {Keyword} {} global\n\
Declare variables to have global scope.\n\
\n\
@example\n\
@group\n\
global @var{x};\n\
if isempty (@var{x})\n\
  x = 1;\n\
endif\n\
@end group\n\
@end example\n\
@seealso{persistent}\n\
@end deftypefn"),

  pair_type ("if",
    "-*- texinfo -*-\n\
@deftypefn  {Keyword} {} if (@var{cond}) @dots{} endif\n\
@deftypefnx {Keyword} {} if (@var{cond}) @dots{} else @dots{} endif\n\
@deftypefnx {Keyword} {} if (@var{cond}) @dots{} elseif (@var{cond}) @dots{} endif\n\
@deftypefnx {Keyword} {} if (@var{cond}) @dots{} elseif (@var{cond}) @dots{} else @dots{} endif\n\
Begin an if block.\n\
\n\
@example\n\
@group\n\
x = 1;\n\
if (x == 1)\n\
  disp (\"one\");\n\
elseif (x == 2)\n\
  disp (\"two\");\n\
else\n\
  disp (\"not one or two\");\n\
endif\n\
@end group\n\
@end example\n\
@seealso{switch}\n\
@end deftypefn"),

  pair_type ("otherwise",
    "-*- texinfo -*-\n\
@deftypefn {Keyword} {} otherwise\n\
The default statement in a switch block (similar to else in an if block).\n\
@seealso{switch}\n\
@end deftypefn"),

  pair_type ("parfor",
    "-*- texinfo -*-\n\
@deftypefn  {Keyword} {} for @var{i} = @var{range}\n\
@deftypefnx {Keyword} {} for (@var{i} = @var{range}, @var{maxproc})\n\
Begin a for loop that may execute in parallel.\n\
\n\
@example\n\
@group\n\
parfor i = 1:10\n\
  i\n\
endparfor\n\
@end group\n\
@end example\n\
@seealso{for, do, while}\n\
@end deftypefn"),

  pair_type ("persistent",
    "-*- texinfo -*-\n\
@deftypefn {Keyword} {} persistent @var{var}\n\
Declare variables as persistent.  A variable that has been declared\n\
persistent within a function will retain its contents in memory between\n\
subsequent calls to the same function.  The difference between persistent\n\
variables and global variables is that persistent variables are local in \n\
scope to a particular function and are not visible elsewhere.\n\
@seealso{global}\n\
@end deftypefn"),

  pair_type ("return",
    "-*- texinfo -*-\n\
@deftypefn {Keyword} {} return\n\
Return from a function.\n\
@seealso{function}\n\
@end deftypefn"),

  pair_type ("static",
    "-*- texinfo -*-\n\
@deftypefn {Keyword} {} static\n\
This function has been deprecated in favor of persistent.\n\
@seealso{persistent}\n\
@end deftypefn"),

  pair_type ("switch",
    "-*- texinfo -*-\n\
@deftypefn {Keyword} {} switch @var{statement}\n\
Begin a switch block.\n\
\n\
@example\n\
@group\n\
yesno = \"yes\"\n\
\n\
switch yesno\n\
  case @{\"Yes\" \"yes\" \"YES\" \"y\" \"Y\"@}\n\
    value = 1;\n\
  case @{\"No\" \"no\" \"NO\" \"n\" \"N\"@}\n\
    value = 0;\n\
  otherwise\n\
    error (\"invalid value\");\n\
endswitch\n\
@end group\n\
@end example\n\
@seealso{if, case, otherwise}\n\
@end deftypefn"),

  pair_type ("try",
    "-*- texinfo -*-\n\
@deftypefn {Keyword} {} try\n\
Begin a try-catch block.\n\
\n\
If an error occurs within a try block, then the catch code will be run and\n\
execution will proceed after the catch block (though it is often\n\
recommended to use the lasterr function to re-throw the error after cleanup\n\
is completed).\n\
@seealso{catch, unwind_protect}\n\
@end deftypefn"),

  pair_type ("until",
    "-*- texinfo -*-\n\
@deftypefn {Keyword} {} until\n\
End a do-until loop.\n\
@seealso{do}\n\
@end deftypefn"),

  pair_type ("unwind_protect",
    "-*- texinfo -*-\n\
@deftypefn {Keyword} {} unwind_protect\n\
Begin an unwind_protect block.\n\
\n\
If an error occurs within the first part of an unwind_protect block\n\
the commands within the unwind_protect_cleanup block are executed before\n\
the error is thrown.  If an error is not thrown, then the\n\
unwind_protect_cleanup block is still executed (in other words, the\n\
unwind_protect_cleanup will be run with or without an error in the\n\
unwind_protect block).\n\
@seealso{unwind_protect_cleanup, try}\n\
@end deftypefn"),

  pair_type ("unwind_protect_cleanup",
    "-*- texinfo -*-\n\
@deftypefn {Keyword} {} unwind_protect_cleanup\n\
Begin the cleanup section of an unwind_protect block.\n\
@seealso{unwind_protect}\n\
@end deftypefn"),

  pair_type ("varargin",
    "-*- texinfo -*-\n\
@deftypefn {Keyword} {} varargin\n\
Pass an arbitrary number of arguments into a function.\n\
@seealso{varargout, nargin, isargout, nargout, nthargout}\n\
@end deftypefn"),

  pair_type ("varargout",
    "-*- texinfo -*-\n\
@deftypefn {Keyword} {} varargout\n\
Pass an arbitrary number of arguments out of a function.\n\
@seealso{varargin, nargin, isargout, nargout, nthargout}\n\
@end deftypefn"),

  pair_type ("while",
    "-*- texinfo -*-\n\
@deftypefn {Keyword} {} while\n\
Begin a while loop.\n\
@seealso{do}\n\
@end deftypefn"),
};

// Return a copy of the operator or keyword names.
static string_vector
names (const map_type& lst)
{
  string_vector retval (lst.size ());
  int j = 0;
  for (map_iter iter = lst.begin (); iter != lst.end (); iter ++)
    retval [j++] = iter->first;
  return retval;
}

const static map_type operators_map (operators, operators + size (operators));
const static map_type keywords_map (keywords, keywords + size (keywords));
const static string_vector keyword_names = names (keywords_map);

// FIXME -- It's not likely that this does the right thing now.

string_vector
make_name_list (void)
{
  const int key_len = keyword_names.length ();

  const string_vector bif = symbol_table::built_in_function_names ();
  const int bif_len = bif.length ();

  const string_vector cfl = symbol_table::cmdline_function_names ();
  const int cfl_len = cfl.length ();

  const string_vector lcl = symbol_table::variable_names ();
  const int lcl_len = lcl.length ();

  const string_vector ffl = load_path::fcn_names ();
  const int ffl_len = ffl.length ();

  const string_vector afl = autoloaded_functions ();
  const int afl_len = afl.length ();

  const int total_len
    = key_len + bif_len + cfl_len + lcl_len + ffl_len + afl_len;

  string_vector list (total_len);

  // Put all the symbols in one big list.

  int j = 0;
  int i = 0;
  for (i = 0; i < key_len; i++)
    list[j++] = keyword_names[i];

  for (i = 0; i < bif_len; i++)
    list[j++] = bif[i];

  for (i = 0; i < cfl_len; i++)
    list[j++] = cfl[i];

  for (i = 0; i < lcl_len; i++)
    list[j++] = lcl[i];

  for (i = 0; i < ffl_len; i++)
    list[j++] = ffl[i];

  for (i = 0; i < afl_len; i++)
    list[j++] = afl[i];

  return list;
}

static bool
looks_like_html (const std::string& msg)
{
  const size_t p1 = msg.find ('\n');
  std::string t = msg.substr (0, p1);
  const size_t p2 = t.find ("<html"); // FIXME: this comparison should be case-insensitive

   return (p2 != std::string::npos);
}

static bool
looks_like_texinfo (const std::string& msg, size_t& p1)
{
  p1 = msg.find ('\n');

  std::string t = msg.substr (0, p1);

  if (p1 == std::string::npos)
    p1 = 0;

  size_t p2 = t.find ("-*- texinfo -*-");

  return (p2 != std::string::npos);
}

static bool
raw_help_from_symbol_table (const std::string& nm, std::string& h,
                            std::string& w, bool& symbol_found)
{
  bool retval = false;

  octave_value val = symbol_table::find_function (nm);

  if (val.is_defined ())
    {
      octave_function *fcn = val.function_value ();

      if (fcn)
        {
          symbol_found = true;

          h = fcn->doc_string ();

          retval = true;

          w = fcn->fcn_file_name ();

          if (w.empty ())
            w = fcn->is_user_function ()
              ? "command-line function" : "built-in function";
        }
    }

  return retval;
}

static bool
raw_help_from_file (const std::string& nm, std::string& h,
                    std::string& file, bool& symbol_found)
{
  bool retval = false;

  // FIXME -- this is a bit of a kluge...
  unwind_protect frame;
  frame.protect_var (reading_script_file);
  reading_script_file = true;

  h = get_help_from_file (nm, symbol_found, file);

  if (h.length () > 0)
    retval = true;

  return retval;
}

static bool
raw_help_from_map (const std::string& nm, std::string& h,
                   const map_type& map, bool& symbol_found)
{
  map_iter idx = map.find (nm);
  symbol_found = (idx != map.end ());
  h = (symbol_found) ? idx->second : "";
  return symbol_found;
}

std::string
raw_help (const std::string& nm, bool& symbol_found)
{
  std::string h;
  std::string w;
  std::string f;

  (raw_help_from_symbol_table (nm, h, w, symbol_found)
   || raw_help_from_file (nm, h, f, symbol_found)
   || raw_help_from_map (nm, h, operators_map, symbol_found)
   || raw_help_from_map (nm, h, keywords_map, symbol_found));

  return h;
}

static void
do_get_help_text (const std::string& name, std::string& text,
                  std::string& format)
{
  bool symbol_found = false;
  text = raw_help (name, symbol_found);

  format = "Not found";
  if (symbol_found)
    {
      size_t idx = -1;
      if (text.empty ())
        {
          format = "Not documented";
        }
      else if (looks_like_texinfo (text, idx))
        {
          format = "texinfo";
          text.erase (0, idx);
        }
      else if (looks_like_html (text))
        {
          format = "html";
        }
      else
        {
          format = "plain text";
        }
    }
}

DEFUN (get_help_text, args, , "-*- texinfo -*-\n\
@deftypefn {Loadable Function} {[@var{text}, @var{format}] =} get_help_text (@var{name})\n\
Return the raw help text of function @var{name}.\n\
\n\
The raw help text is returned in @var{text} and the format in @var{format}\n\
The format is a string which is one of @t{\"texinfo\"}, @t{\"html\"}, or\n\
@t{\"plain text\"}.\n\
@end deftypefn")
{
  octave_value_list retval;

  if (args.length () == 1)
    {
      const std::string name = args (0).string_value ();

      if (! error_state)
        {
          std::string text;
          std::string format;

          do_get_help_text (name, text, format);

          retval(1) = format;
          retval(0) = text;
        }
      else
        error ("get_help_text: invalid input");
    }
  else
    print_usage ();

  return retval;
}

static void
do_get_help_text_from_file (const std::string& fname, std::string& text,
                            std::string& format)
{
  bool symbol_found = false;

  std::string f;

  raw_help_from_file (fname, text, f, symbol_found);

  format = "Not found";
  if (symbol_found)
    {
      size_t idx = -1;
      if (text.empty ())
        {
          format = "Not documented";
        }
      else if (looks_like_texinfo (text, idx))
        {
          format = "texinfo";
          text.erase (0, idx);
        }
      else if (looks_like_html (text))
        {
          format = "html";
        }
      else
        {
          format = "plain text";
        }
    }
}

DEFUN (get_help_text_from_file, args, ,
  "-*- texinfo -*-\n\
@deftypefn {Loadable Function} {[@var{text}, @var{format}] =} get_help_text_from_file (@var{fname})\n\
Return the raw help text from the file @var{fname}.\n\
\n\
The raw help text is returned in @var{text} and the format in @var{format}\n\
The format is a string which is one of @t{\"texinfo\"}, @t{\"html\"}, or\n\
@t{\"plain text\"}.\n\
@end deftypefn")
{
  octave_value_list retval;

  if (args.length () == 1)
    {
      const std::string fname = args(0).string_value ();

      if (! error_state)
        {
          std::string text;
          std::string format;

          do_get_help_text_from_file (fname, text, format);

          retval(1) = format;
          retval(0) = text;
        }
      else
        error ("get_help_text_from_file: invalid input");
    }
  else
    print_usage ();

  return retval;
}

// Return a cell array of strings containing the names of all
// operators.

DEFUN (__operators__, , ,
  "-*- texinfo -*-\n\
@deftypefn {Function File} __operators__ ()\n\
Undocumented internal function.\n\
@end deftypefn")
{
  return octave_value (Cell (names (operators_map)));
}

// Return a cell array of strings containing the names of all
// keywords.

DEFUN (__keywords__, , ,
  "-*- texinfo -*-\n\
@deftypefn {Function File} __keywords__ ()\n\
Undocumented internal function.\n\
@end deftypefn")
{
  return octave_value (Cell (names (keywords_map)));
}

// Return a cell array of strings containing the names of all builtin
// functions.

DEFUN (__builtins__, , ,
  "-*- texinfo -*-\n\
@deftypefn {Function File} __builtins__ ()\n\
Undocumented internal function.\n\
@end deftypefn")
{
  const string_vector bif = symbol_table::built_in_function_names ();

  return octave_value (Cell (bif));
}

static std::string
do_which (const std::string& name, std::string& type)
{
  std::string file;

  type = std::string ();

  octave_value val = symbol_table::find_function (name);

  if (name.find_first_of ('.') == std::string::npos)
    {
      if (val.is_defined ())
        {
          octave_function *fcn = val.function_value ();

          if (fcn)
            {
              file = fcn->fcn_file_name ();

              if (file.empty ())
                {
                  if (fcn->is_user_function ())
                    type = "command-line function";
                  else
                    type = "built-in function";
                }
              else
                type = val.is_user_script ()
                  ? std::string ("script") : std::string ("function");
            }
        }
      else
        {
          // We might find a file that contains only a doc string.

          file = load_path::find_fcn_file (name);
        }
    }
  else
    {
      // File query.

      // For compatibility: "file." queries "file".
      if (name.size () > 1 && name[name.size () - 1] == '.')
        file = load_path::find_file (name.substr (0, name.size () - 1));
      else
        file = load_path::find_file (name);
    }


  return file;
}

std::string
do_which (const std::string& name)
{
  std::string retval;

  std::string type;

  retval = do_which (name, type);

  return retval;
}

DEFUN (__which__, args, ,
  "-*- texinfo -*-\n\
@deftypefn {Built-in Function} {} __which__ (@var{name}, @dots{})\n\
Undocumented internal function.\n\
@end deftypefn")
{
  octave_value retval;

  string_vector argv = args.make_argv ("which");

  if (! error_state)
    {
      int argc = argv.length ();

      if (argc > 1)
        {
          octave_map m (dim_vector (1, argc-1));

          Cell names (1, argc-1);
          Cell files (1, argc-1);
          Cell types (1, argc-1);

          for (int i = 1; i < argc; i++)
            {
              std::string name = argv[i];

              std::string type;

              std::string file = do_which (name, type);

              names(i-1) = name;
              files(i-1) = file;
              types(i-1) = type;
            }

          m.assign ("name", names);
          m.assign ("file", files);
          m.assign ("type", types);

          retval = m;
        }
      else
        print_usage ();
    }

  return retval;
}

// FIXME -- Are we sure this function always does the right thing?
inline bool
file_is_in_dir (const std::string filename, const std::string dir)
{
  if (filename.find (dir) == 0)
    {
      const int dir_len = dir.size ();
      const int filename_len = filename.size ();
      const int max_allowed_seps = file_ops::is_dir_sep (dir [dir_len-1]) ? 0 : 1;

      int num_seps = 0;
      for (int i = dir_len; i < filename_len; i++)
        if (file_ops::is_dir_sep (filename [i]))
          num_seps ++;

      return (num_seps <= max_allowed_seps);
    }
  else
    return false;
}

// Return a cell array of strings containing the names of all
// functions available in DIRECTORY.  If no directory is given, search
// the current path.

DEFUN (__list_functions__, args, ,
  "-*- texinfo -*-\n\
@deftypefn  {Function File} {@var{retval} =} __list_functions__ ()\n\
@deftypefnx {Function File} {@var{retval} =} __list_functions__ (@var{directory})\n\
Undocumented internal function.\n\
@end deftypefn")
{
  octave_value retval;

  // Get list of functions
  string_vector ffl = load_path::fcn_names ();
  string_vector afl = autoloaded_functions ();

  if (args.length () == 0)
    retval = Cell (ffl.append (afl));
  else
    {
      std::string dir = args (0).string_value ();

      if (! error_state)
        {
          string_vector fl = load_path::files (dir, true);

          if (! error_state)
            {
              // Return a sorted list with unique entries (in case of
              // .m and .oct versions of the same function in a given
              // directory, for example).
              fl.sort (true);

              retval = Cell (fl);
            }
        }
      else
        error ("__list_functions__: DIRECTORY argument must be a string");
    }

  return retval;
}

DEFUN (doc_cache_file, args, nargout,
  "-*- texinfo -*-\n\
@deftypefn  {Built-in Function} {@var{val} =} doc_cache_file ()\n\
@deftypefnx {Built-in Function} {@var{old_val} =} doc_cache_file (@var{new_val})\n\
@deftypefnx {Built-in Function} {} doc_cache_file (@var{new_val}, \"local\")\n\
Query or set the internal variable that specifies the name of the\n\
Octave documentation cache file.  A cache file significantly improves\n\
the performance of the @code{lookfor} command.  The default value is \n\
@file{@var{octave-home}/share/octave/@var{version}/etc/doc-cache},\n\
in which @var{octave-home} is the root directory of the Octave installation,\n\
and @var{version} is the Octave version number.\n\
The default value may be overridden by the environment variable\n\
@w{@env{OCTAVE_DOC_CACHE_FILE}}, or the command line argument\n\
@samp{--doc-cache-file NAME}.\n\
\n\
When called from inside a function with the \"local\" option, the variable is\n\
changed locally for the function and any subroutines it calls.  The original\n\
variable value is restored when exiting the function.\n\
@seealso{lookfor, info_program, doc, help, makeinfo_program}\n\
@end deftypefn")
{
  return SET_NONEMPTY_INTERNAL_STRING_VARIABLE (doc_cache_file);
}

DEFUN (info_file, args, nargout,
  "-*- texinfo -*-\n\
@deftypefn  {Built-in Function} {@var{val} =} info_file ()\n\
@deftypefnx {Built-in Function} {@var{old_val} =} info_file (@var{new_val})\n\
@deftypefnx {Built-in Function} {} info_file (@var{new_val}, \"local\")\n\
Query or set the internal variable that specifies the name of the\n\
Octave info file.  The default value is\n\
@file{@var{octave-home}/info/octave.info}, in\n\
which @var{octave-home} is the root directory of the Octave installation.\n\
The default value may be overridden by the environment variable\n\
@w{@env{OCTAVE_INFO_FILE}}, or the command line argument\n\
@samp{--info-file NAME}.\n\
\n\
When called from inside a function with the \"local\" option, the variable is\n\
changed locally for the function and any subroutines it calls.  The original\n\
variable value is restored when exiting the function.\n\
@seealso{info_program, doc, help, makeinfo_program}\n\
@end deftypefn")
{
  return SET_NONEMPTY_INTERNAL_STRING_VARIABLE (info_file);
}

DEFUN (info_program, args, nargout,
  "-*- texinfo -*-\n\
@deftypefn  {Built-in Function} {@var{val} =} info_program ()\n\
@deftypefnx {Built-in Function} {@var{old_val} =} info_program (@var{new_val})\n\
@deftypefnx {Built-in Function} {} info_program (@var{new_val}, \"local\")\n\
Query or set the internal variable that specifies the name of the\n\
info program to run.  The default value is\n\
@file{@var{octave-home}/libexec/octave/@var{version}/exec/@var{arch}/info}\n\
in which @var{octave-home} is the root directory of the Octave installation,\n\
@var{version} is the Octave version number, and @var{arch}\n\
is the system type (for example, @code{i686-pc-linux-gnu}).  The\n\
default value may be overridden by the environment variable\n\
@w{@env{OCTAVE_INFO_PROGRAM}}, or the command line argument\n\
@samp{--info-program NAME}.\n\
\n\
When called from inside a function with the \"local\" option, the variable is\n\
changed locally for the function and any subroutines it calls.  The original\n\
variable value is restored when exiting the function.\n\
@seealso{info_file, doc, help, makeinfo_program}\n\
@end deftypefn")
{
  return SET_NONEMPTY_INTERNAL_STRING_VARIABLE (info_program);
}

DEFUN (makeinfo_program, args, nargout,
  "-*- texinfo -*-\n\
@deftypefn  {Built-in Function} {@var{val} =} makeinfo_program ()\n\
@deftypefnx {Built-in Function} {@var{old_val} =} makeinfo_program (@var{new_val})\n\
@deftypefnx {Built-in Function} {} makeinfo_program (@var{new_val}, \"local\")\n\
Query or set the internal variable that specifies the name of the\n\
program that Octave runs to format help text containing\n\
Texinfo markup commands.  The default value is @code{makeinfo}.\n\
\n\
When called from inside a function with the \"local\" option, the variable is\n\
changed locally for the function and any subroutines it calls.  The original\n\
variable value is restored when exiting the function.\n\
@seealso{info_file, info_program, doc, help}\n\
@end deftypefn")
{
  return SET_NONEMPTY_INTERNAL_STRING_VARIABLE (makeinfo_program);
}

DEFUN (suppress_verbose_help_message, args, nargout,
  "-*- texinfo -*-\n\
@deftypefn  {Built-in Function} {@var{val} =} suppress_verbose_help_message ()\n\
@deftypefnx {Built-in Function} {@var{old_val} =} suppress_verbose_help_message (@var{new_val})\n\
@deftypefnx {Built-in Function} {} suppress_verbose_help_message (@var{new_val}, \"local\")\n\
Query or set the internal variable that controls whether Octave\n\
will add additional help information to the end of the output from\n\
the @code{help} command and usage messages for built-in commands.\n\
\n\
When called from inside a function with the \"local\" option, the variable is\n\
changed locally for the function and any subroutines it calls.  The original\n\
variable value is restored when exiting the function.\n\
@end deftypefn")
{
  return SET_INTERNAL_VARIABLE (suppress_verbose_help_message);
}