#
#       Gnu.pm --- The GNU Readline/History Library wrapper module
#
#       Copyright (c) 1996-2022 Hiroo Hayashi.  All rights reserved.
#
#       This program is free software; you can redistribute it and/or
#       modify it under the same terms as Perl itself.
#
#       Some of documentation strings in this file are cited from the
#       GNU Readline/History Library Manual.

package Term::ReadLine::Gnu;

=head1 NAME

Term::ReadLine::Gnu - Perl extension for the GNU Readline/History Library

=head1 SYNOPSIS

  use Term::ReadLine;   # Do not "use Term::ReadLine::Gnu;"
  $term = new Term::ReadLine 'ProgramName';
  while ( defined ($_ = $term->readline('prompt>')) ) {
    ...
  }

=head1 DESCRIPTION

=head2 Overview

This is an implementation of
L<Term::ReadLine|http://search.cpan.org/dist/Term-ReadLine/> using
L<the GNU ReadlineE<sol>History
Library|https://tiswww.cwru.edu/php/chet/readline/rltop.html>.

For basic functions object oriented interface is provided. These are
described in the section L</"Standard Methods"> and
L</"C<Term::ReadLine::Gnu> Functions">.

This package also has the interface with the almost all functions and
variables which are documented in the GNU Readline/History Library
Manual.  They are documented in the section
L</"C<Term::ReadLine::Gnu> Functions">
and
L</"C<Term::ReadLine::Gnu>
Variables"> briefly.  For further details of the GNU Readline/History
Library, see L<GNU Readline Library
Manual|https://tiswww.cwru.edu/php/chet/readline/readline.html> and
L<GNU History Library
Manual|https://tiswww.cwru.edu/php/chet/readline/history.html>.

There are some C<Term::ReadLine::Gnu> original features.  They are
described in the section L</"C<Term::ReadLine::Gnu> Specific
Features">

The sample programs under F<eg/> directory and test programs under
F<t/> directory in L<the C<Term::ReadLine::Gnu> distribution|http://search.cpan.org/dist/Term-ReadLine-Gnu/> include
many examples of this module.

=head2 Standard Methods

These are standard methods defined by
L<Term::ReadLine|http://search.cpan.org/dist/Term-ReadLine/>.

=cut

use strict;
use warnings;
use Carp;
# use version TRG-1.22 for perl 5.7.x, or TRG-1.09 for older Perl
use 5.8.1;

# This module can't be loaded directly.
BEGIN {
    if (not defined $Term::ReadLine::VERSION) {
        croak <<END;
It is invalid to load Term::ReadLine::Gnu directly.  Please consult
the Term::ReadLine documentation for more information.
END
    }
}

BEGIN {
    # https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=99843
    $ENV{TERM} = 'dumb' unless defined($ENV{TERM});

    # Use Term::ReadLine::Stub in Emacs
    # as bash does not do line-editing in the case. (cf. bash-5.2/shell.c)
    # https://rt.cpan.org/Ticket/Display.html?id=123398
    # https://github.com/hirooih/perl-trg/issues/11
    if ($ENV{TERM} eq "emacs" || defined($ENV{EMACS}) || defined($ENV{INSIDE_EMACS})) {
        croak "Use Term::ReadLine::Stub.";
    }
}

{
    use Exporter ();
    use DynaLoader;

    our $VERSION = '1.45';              # update Gnu::XS::VERSION also.

    # Term::ReadLine::Gnu::AU makes a function in
    # `Term::ReadLine::Gnu::XS' as a method.
    # The namespace of Term::ReadLine::Gnu::AU is searched before ones
    # of other classes

    our @ISA = qw(Term::ReadLine::Gnu::AU Term::ReadLine::Stub
                  Exporter DynaLoader);

    our %EXPORT_TAGS = (
        prompt =>       [qw(RL_PROMPT_START_IGNORE RL_PROMPT_END_IGNORE)],
        match_type =>   [qw(NO_MATCH SINGLE_MATCH MULT_MATCH)],
        keymap_type =>  [qw(ISFUNC ISKMAP ISMACR)],
        undo_code =>    [qw(UNDO_DELETE UNDO_INSERT UNDO_BEGIN UNDO_END)],
        rl_state =>     [qw(RL_STATE_NONE RL_STATE_INITIALIZING
                            RL_STATE_INITIALIZED RL_STATE_TERMPREPPED
                            RL_STATE_READCMD RL_STATE_METANEXT
                            RL_STATE_DISPATCHING RL_STATE_MOREINPUT
                            RL_STATE_ISEARCH RL_STATE_NSEARCH
                            RL_STATE_SEARCH RL_STATE_NUMERICARG
                            RL_STATE_MACROINPUT RL_STATE_MACRODEF
                            RL_STATE_OVERWRITE RL_STATE_COMPLETING
                            RL_STATE_SIGHANDLER RL_STATE_UNDOING
                            RL_STATE_INPUTPENDING RL_STATE_TTYCSAVED
                            RL_STATE_CALLBACK RL_STATE_VIMOTION
                            RL_STATE_MULTIKEY RL_STATE_VICMDONCE
                            RL_STATE_CHARSEARCH RL_STATE_REDISPLAYING
                            RL_STATE_DONE RL_STATE_TIMEOUT
                            RL_STATE_EOF
                            )],
        );
    Exporter::export_ok_tags('prompt');
    Exporter::export_ok_tags('match_type');
    Exporter::export_ok_tags('keymap_type');
    Exporter::export_ok_tags('undo_code');
    Exporter::export_ok_tags('rl_state');

    bootstrap Term::ReadLine::Gnu $VERSION; # DynaLoader
}
require Term::ReadLine::Gnu::XS;

#       Global Variables

our($readline_version);

# Each variable in the GNU Readline Library is tied to an entry of
# this hash (%Attribs).  By accessing the hash entry, you can read
# and/or write the variable in the GNU Readline Library.  See the
# package definition of Term::ReadLine::Gnu::Var and following code
# for further details.

# Normal (non-tied) entries
our %Attribs  = (
    MinLength => 1,
    do_expand => 0,
    completion_word => [],
    term_set => ['', '', '', ''],
    );
our %Features = (
    appname => 1, minline => 1, autohistory => 1,
    getHistory => 1, setHistory => 1, addHistory => 1,
    readHistory => 1, writeHistory => 1,
    preput => 1, attribs => 1, newTTY => 1,
    tkRunning => Term::ReadLine::Stub->Features->{'tkRunning'},
    ornaments => Term::ReadLine::Stub->Features->{'ornaments'},
    stiflehistory => 1,
    );

#
#       GNU Readline/History Library constant definition
#       These are included in @EXPORT_OK.

# I can define these variables in XS code to use the value defined in
# readline.h, etc.  But it needs some calling convention change and
# will cause compatiblity problem. I hope the definition of these
# constant value will not be changed.

# for non-printing characters in prompt string
sub RL_PROMPT_START_IGNORE      { "\001"; }
sub RL_PROMPT_END_IGNORE        { "\002"; }

# for rl_filename_quoting_function
sub NO_MATCH     { 0; }
sub SINGLE_MATCH { 1; }
sub MULT_MATCH   { 2; }

# for rl_generic_bind, rl_function_of_keyseq
sub ISFUNC      { 0; }
sub ISKMAP      { 1; }
sub ISMACR      { 2; }

# for rl_add_undo
sub UNDO_DELETE { 0; }
sub UNDO_INSERT { 1; }
sub UNDO_BEGIN  { 2; }
sub UNDO_END    { 3; }

# for rl_readline_state which was implemented since 4.2
sub RL_STATE_NONE               { 0x00000; } # no state; before first call
sub RL_STATE_INITIALIZING       { 0x00001; } # initializing
sub RL_STATE_INITIALIZED        { 0x00002; } # initialization done
sub RL_STATE_TERMPREPPED        { 0x00004; } # terminal is prepped
sub RL_STATE_READCMD            { 0x00008; } # reading a command key
sub RL_STATE_METANEXT           { 0x00010; } # reading input after ESC
sub RL_STATE_DISPATCHING        { 0x00020; } # dispatching to a command
sub RL_STATE_MOREINPUT          { 0x00040; } # reading more input in a command function
sub RL_STATE_ISEARCH            { 0x00080; } # doing incremental search
sub RL_STATE_NSEARCH            { 0x00100; } # doing non-inc search
sub RL_STATE_SEARCH             { 0x00200; } # doing a history search
sub RL_STATE_NUMERICARG         { 0x00400; } # reading numeric argument
sub RL_STATE_MACROINPUT         { 0x00800; } # getting input from a macro
sub RL_STATE_MACRODEF           { 0x01000; } # defining keyboard macro
sub RL_STATE_OVERWRITE          { 0x02000; } # overwrite mode
sub RL_STATE_COMPLETING         { 0x04000; } # doing completion
sub RL_STATE_SIGHANDLER         { 0x08000; } # in readline sighandler
sub RL_STATE_UNDOING            { 0x10000; } # doing an undo
sub RL_STATE_INPUTPENDING       { 0x02_0000; } # rl_execute_next called
sub RL_STATE_TTYCSAVED          { 0x04_0000; } # tty special chars saved [5.0]
sub RL_STATE_CALLBACK           { 0x08_0000; } # using the callback interface [5.1]
sub RL_STATE_VIMOTION           { 0x10_0000; } # reading vi motion arg [5.1]
sub RL_STATE_MULTIKEY           { 0x20_0000; } # reading multiple-key command [5.1]
sub RL_STATE_VICMDONCE          { 0x40_0000; } # entered vi command mode at least once [5.1]
sub RL_STATE_CHARSEARCH         { 0x80_0000; } # vi mode char search [7.0]
sub RL_STATE_REDISPLAYING       {              # updating terminal display [6.1]
    $readline_version < 0x0700 ? 0x80_0000 : 0x100_0000;
}
sub RL_STATE_DONE {                            # done; accepted line
    $readline_version < 0x0501 ? 0x8_0000 :
        ($readline_version < 0x0601 ? 0x80_0000 :
         ($readline_version < 0x0700 ? 0x100_0000 : 0x200_0000));
}
sub RL_STATE_TIMEOUT            { 0x400_0000; } # [8.2]
sub RL_STATE_EOF                { 0x800_0000; } # [8.2]

#
#       Methods Definition
#

=over 4

=item C<ReadLine>

returns the actual package that executes the commands. If
this package is being used, C<Term::ReadLine::Gnu> is returned.

=cut

sub ReadLine { 'Term::ReadLine::Gnu'; }

=item C<new(NAME,[IN,OUT])>

returns the handle for subsequent calls to following functions.
Argument is the name of the application.  Optionally can be followed
by two arguments for C<IN> and C<OUT> file handles. These arguments
should be globs.

=cut

# The origin of this function is Term::ReadLine::Perl.pm by Ilya Zakharevich.
sub new {
    my $this = shift;           # Package
    my $class = ref($this) || $this;

    # Debian Bug Report #204362
    croak "Wrong number of arguments" unless @_ == 1 or @_ == 3;
    my $name = shift;

    my $self = \%Attribs;
    bless $self, $class;

    # set rl_readline_name before .inputrc is read in rl_initialize()
    $Attribs{readline_name} = $name;

    # on MSWin32 setting $ENV{TERM} does not affect on getenv() in XS
    if ($^O eq 'MSWin32') {
        $Attribs{terminal_name} = $ENV{TERM};
    }

    # some version of Perl cause segmentation fault, if XS module
    # calls setenv() before the 1st assignment to $ENV{}.
    $ENV{_TRL_DUMMY} = '';

    # UTF-8 condition conpatible with Term:ReadLine
    $Attribs{utf8_mode} ||= ${^UNICODE} & 1 || defined ${^ENCODING};
    #printf "\${^UNICODE}: 0x%X, ", ${^UNICODE};
    #print "\${^ENCODING}: ", defined ${^ENCODING} ? 'defined' : 'undef', "\n";

    # set tty before calling rl_initialize() not to output some
    # charactores to STDIO.
    # https://rt.cpan.org/Ticket/Display.html?id=96569
    if (!@_) {
        my ($in, $out) = $self->findConsole();
        open(my $IN,"<$in")   || croak "Cannot open $in for read";
        open(my $OUT,">$out") || croak "Cannot open $out for write";
        if ($Attribs{utf8_mode}) {
            binmode $IN,  ':encoding(UTF-8)'; # not necessary
            binmode $OUT, ':encoding(UTF-8)';
        }
        $self->newTTY($IN, $OUT);
    } else {
        # enable UTF-8 mode if input stream has the utf8 layer.
        my @layers = PerlIO::get_layers($_[0]);
        $Attribs{utf8_mode} ||= ($layers[$#layers] eq 'utf8');

        $self->newTTY(@_);
    }

    # initialize the GNU Readline Library and termcap library
    # This calls tgetent().
    $self->initialize();

    # enable ornaments to be compatible with perl5.004_05(?)
    # This calls tgetstr().
    $self->ornaments(1) unless ($ENV{PERL_RL} and $ENV{PERL_RL} =~ /\bo\w*=0/);

    # keep rl_readline_version value for efficiency
    $readline_version = $Attribs{readline_version};

    # bind operate-and-get-next to \C-o by default for the compatibility
    # with bash and Term::ReadLine::Perl
    # GNU Readline 8.1 and later support operate-and-get-next natively.
    Term::ReadLine::Gnu::XS::rl_add_defun('operate-and-get-next',
                                          \&Term::ReadLine::Gnu::XS::operate_and_get_next, ord "\co")
        if ($readline_version < 0x801);

    $self;
}

sub DESTROY {}

=item C<readline(PROMPT[,PREPUT])>

gets an input line, with actual C<GNU Readline> support.  Trailing
newline is removed.  Returns C<undef> on C<EOF>.  C<PREPUT> is an
optional argument meaning the initial value of input.

The optional argument C<PREPUT> is granted only if the value C<preput>
is in C<Features>.

C<PROMPT> may include some escape sequences.  Use
C<RL_PROMPT_START_IGNORE> to begin a sequence of non-printing
characters, and C<RL_PROMPT_END_IGNORE> to end the sequence.

=cut

# to peacify -w
$Term::ReadLine::registered = $Term::ReadLine::registered;

sub readline {                  # should be ReadLine
    my $self = shift;
    my ($prompt, $preput) = @_;

    # A contributed fix for Perl debugger
    # make sure the outstream fd inside the readline library is
    # in sync (see http://bugs.debian.org/236018)
    # This is not a real fix but left for system where this fix works.
    # Here is the real fix for perl5db.pl.
    # https://rt.perl.org/Public/Bug/Display.html?id=121456
    $Attribs{outstream} = $Attribs{outstream};

    # ornament support (now prompt only)
    $prompt = ${$Attribs{term_set}}[0] . $prompt . ${$Attribs{term_set}}[1];

    # `completion_function' support for compatibility with
    # Term:ReadLine::Perl.  Prefer $completion_entry_function, since a
    # program which uses $completion_entry_function should know
    # Term::ReadLine::Gnu and have better completion function using
    # the variable.
    $Attribs{completion_entry_function} = $Attribs{_trp_completion_function}
        if (!defined $Attribs{completion_entry_function}
            && defined $Attribs{completion_function});

    # TkRunning support
    if (not $Term::ReadLine::registered and $Term::ReadLine::toloop
        and defined &Tk::DoOneEvent) {
        $self->register_Tk;
        $Attribs{getc_function} = $Attribs{Tk_getc};
    }

    # call readline()
    my $line;
    if (defined $preput) {
        my $saved_startup_hook = $Attribs{startup_hook};
        $Attribs{startup_hook} = sub {
            $self->rl_insert_text($preput);
            &$saved_startup_hook
                if defined $saved_startup_hook;
        };
        $line = $self->rl_readline($prompt);
        $Attribs{startup_hook} = $saved_startup_hook;
    } else {
        $line = $self->rl_readline($prompt);
    }
    return undef unless defined $line;

    # history expansion
    if ($Attribs{do_expand}) {
        my $result;
        ($result, $line) = $self->history_expand($line);
        my $outstream = $Attribs{outstream};
        print $outstream "$line\n" if ($result);

        # return without adding line into history
        if ($result < 0 || $result == 2) {
            return '';          # don't return `undef' which means EOF.
        }
    }

    # add to history buffer
    $self->add_history($line)
        if (defined $self->{MinLength} && $self->{MinLength} > 0
            && length($line) >= $self->{MinLength});

    return $line;
}

=item C<AddHistory(LINE1, LINE2, ...)>

adds the lines to the history of input, from where it can be used if
the actual C<readline> is present.

=cut

#use vars '*addhistory';
*addhistory = \&AddHistory;     # for backward compatibility

sub AddHistory {
    my $self = shift;
    foreach (@_) {
        $self->add_history($_);
    }
}

=item C<IN>, C<OUT>

return the file handles for input and output or C<undef> if
C<readline> input and output cannot be used for Perl.

=cut

sub IN  { $Attribs{instream}; }
sub OUT { $Attribs{outstream}; }

=item C<MinLine([MAX])>

If argument C<MAX> is specified, it is an advice on minimal size of
line to be included into history.  C<undef> means do not include
anything into history.  Returns the old value.

=cut

sub MinLine {
    my $self = shift;
    my $old_minlength = $self->{MinLength};
    $self->{MinLength} = shift;
    $old_minlength;
}

=item C<findConsole>

returns an array with two strings that give most appropriate names for
files for input and output using conventions C<"E<lt>$in">, C<"E<gt>$out">.

=cut

# findConsole is defined in ReadLine.pm.

=item C<Attribs>

returns a reference to a hash which describes internal configuration
(variables) of the package.  Names of keys in this hash conform to
standard conventions with the leading C<rl_> stripped.

See section L</"C<Term::ReadLine::Gnu> Variables"> for supported variables.

=cut

sub Attribs { \%Attribs; }

=item C<Features>

Returns a reference to a hash with keys being features present in
current implementation. Several optional features are used in the
minimal interface: C<appname> should be present if the first argument
to C<new> is recognized, and C<minline> should be present if
C<MinLine> method is not dummy.  C<autohistory> should be present if
lines are put into history automatically (maybe subject to
C<MinLine>), and C<addHistory> if C<AddHistory> method is not dummy.
C<preput> means the second argument to C<readline> method is processed.
C<getHistory> and C<setHistory> denote that the corresponding methods are
present. C<tkRunning> denotes that a Tk application may run while ReadLine
is getting input.

=cut

sub Features { \%Features; }

=item C<tkRunning>

makes Tk event loop run when waiting for user input (i.e., during
C<readline> method).

=cut

# tkRunning is defined in ReadLine.pm.

=item C<event_loop>

See the description of C<event_loop> on
L<Term::ReadLine|http://search.cpan.org/dist/Term-ReadLine/>.

=item C<ornaments>

makes the command line stand out by using termcap data.  The argument
to C<ornaments> should be 0, 1, or a string of a form
C<"aa,bb,cc,dd">.  Four components of this string should be names of
I<terminal capacities>, first two will be issued to make the prompt
standout, last two to make the input line standout.

=cut

sub ornaments {
    my $self = shift;
    return Term::ReadLine::Gnu::XS::ornaments(@_);
}

=item C<newTTY>

takes two arguments which are input filehandle and output filehandle.
Switches to use these filehandles.

=cut

# used by a program (ex. perldb5.pl) who changes input/output stream.
sub newTTY {
    my ($self, $in, $out) = @_;

    # borrowed from Term/ReadLine.pm
    my $sel = select($out);
    $| = 1;                     # for DB::OUT
    select($sel);

    $Attribs{instream}  = $in;
    $Attribs{outstream} = $out;
}

=item C<enableUTF8>

Enables UTF-8 support.

If STDIN is in UTF-8 by the C<-C> command-line switch or
C<PERL_UNICODE> environment variable, or C<IN> file handle has C<utf8>
IO layer, then UTF-8 support is also enabled.  In other cases you need
this C<enableUTF8> method.

This is an original method of C<Term::ReadLine:Gnu>.

=cut

sub enableUTF8 {
    my $self = shift;
    $Attribs{utf8_mode} = 1;
    binmode $self->IN,  ':encoding(UTF-8)'; # not necessary
    binmode $self->OUT, ':encoding(UTF-8)';
}

=back

=cut

# documented later
sub CallbackHandlerInstall {
    my $self = shift;
    my ($prompt, $lhandler) = @_;

    $Attribs{_callback_handler} = $lhandler;

    # ornament support (now prompt only)
    $prompt = ${$Attribs{term_set}}[0] . $prompt . ${$Attribs{term_set}}[1];

    $Attribs{completion_entry_function} = $Attribs{_trp_completion_function}
        if (!defined $Attribs{completion_entry_function}
            && defined $Attribs{completion_function});

    $self->rl_callback_handler_install($prompt,
                                       \&Term::ReadLine::Gnu::XS::_ch_wrapper);
}


#
#       Additional Supported Methods
#

# Documentation is after '__END__' for efficiency.

# for backward compatibility
#use vars qw(*AddDefun *BindKey *UnbindKey *ParseAndBind *StifleHistory);
*AddDefun = \&add_defun;
*BindKey = \&bind_key;
*UnbindKey = \&unbind_key;
*ParseAndBind = \&parse_and_bind;
*StifleHistory = \&stifle_history;

sub SetHistory {
    my $self = shift;
    $self->clear_history();
    $self->AddHistory(@_);
}

sub GetHistory {
    my $self = shift;
    $self->history_list();
}

sub ReadHistory {
    my $self = shift;
    ! $self->read_history_range(@_);
}

sub WriteHistory {
    my $self = shift;
    ! $self->write_history(@_);
}

#
#       Access Routines for GNU Readline/History Library Variables
#
package Term::ReadLine::Gnu::Var;
use Carp;
use strict;
use warnings;
our %_rl_vars;

%_rl_vars
    = (
       rl_line_buffer                           => ['S', 0],
       rl_prompt                                => ['S', 1],
       rl_library_version                       => ['S', 2],
       rl_terminal_name                         => ['S', 3],
       rl_readline_name                         => ['S', 4],
       rl_basic_word_break_characters           => ['S', 5],
       rl_basic_quote_characters                => ['S', 6],
       rl_completer_word_break_characters       => ['S', 7],
       rl_completer_quote_characters            => ['S', 8],
       rl_filename_quote_characters             => ['S', 9],
       rl_special_prefixes                      => ['S', 10],
       history_no_expand_chars                  => ['S', 11],
       history_search_delimiter_chars           => ['S', 12],
       rl_executing_macro                       => ['S', 13], # GRL 4.2
       history_word_delimiters                  => ['S', 14], # GRL 4.2
       rl_display_prompt                        => ['S', 15], # GRL 6.0
       rl_executing_keyseq                      => ['S', 16], # GRL 6.3

       rl_point                                 => ['I', 0],
       rl_end                                   => ['I', 1],
       rl_mark                                  => ['I', 2],
       rl_done                                  => ['I', 3],
       rl_pending_input                         => ['I', 4],
       rl_completion_query_items                => ['I', 5],
       rl_completion_append_character           => ['C', 6],
       rl_ignore_completion_duplicates          => ['I', 7],
       rl_filename_completion_desired           => ['I', 8],
       rl_filename_quoting_desired              => ['I', 9],
       rl_inhibit_completion                    => ['I', 10],
       history_base                             => ['I', 11],
       history_length                           => ['I', 12],
       history_max_entries                      => ['I', 13],
       max_input_history                        => ['I', 13], # before GRL 4.2
       history_write_timestamps                 => ['I', 14], # GRL 5.0
       history_expansion_char                   => ['C', 15],
       history_subst_char                       => ['C', 16],
       history_comment_char                     => ['C', 17],
       history_quotes_inhibit_expansion         => ['I', 18],
       rl_erase_empty_line                      => ['I', 19], # GRL 4.0
       rl_catch_signals                         => ['I', 20], # GRL 4.0
       rl_catch_sigwinch                        => ['I', 21], # GRL 4.0
       rl_already_prompted                      => ['I', 22], # GRL 4.1
       rl_num_chars_to_read                     => ['I', 23], # GRL 4.1
       rl_dispatching                           => ['I', 24], # GRL 4.2
       rl_gnu_readline_p                        => ['I', 25], # GRL 4.1
       rl_readline_state                        => ['I', 26], # GRL 4.2
       rl_explicit_arg                          => ['I', 27], # GRL 4.2
       rl_numeric_arg                           => ['I', 28], # GRL 4.2
       rl_editing_mode                          => ['I', 29], # GRL 4.2
       rl_attempted_completion_over             => ['I', 30], # GRL 4.2
       rl_completion_type                       => ['I', 31], # GRL 4.2
       rl_readline_version                      => ['I', 32], # GRL 4.2a
       rl_completion_suppress_append            => ['I', 33], # GRL 4.3
       rl_completion_quote_character            => ['C', 34], # GRL 5.0
       rl_completion_suppress_quote             => ['I', 35], # GRL 5.0
       rl_completion_found_quote                => ['I', 36], # GRL 5.0
       rl_completion_mark_symlink_dirs          => ['I', 37], # GRL 4.3
       rl_prefer_env_winsize                    => ['I', 38], # GRL 5.1
       rl_sort_completion_matches               => ['I', 39], # GRL 6.0
       rl_completion_invoking_key               => ['C', 40], # GRL 6.0
       rl_executing_key                         => ['I', 41], # GRL 6.3
       rl_key_sequence_length                   => ['I', 42], # GRL 6.3
       rl_change_environment                    => ['I', 43], # GRL 6.3
       rl_persistent_signal_handlers            => ['I', 44], # GRL 7.0
       history_quoting_state                    => ['I', 45], # GRL 8.0
       utf8_mode                                => ['I', 46], # internal
       rl_eof_found                             => ['I', 47], # GRL 8.2

       rl_startup_hook                          => ['F', 0],
       rl_event_hook                            => ['F', 1],
       rl_getc_function                         => ['F', 2],
       rl_redisplay_function                    => ['F', 3],
       rl_completion_entry_function             => ['F', 4],
       rl_attempted_completion_function         => ['F', 5],
       rl_filename_quoting_function             => ['F', 6],
       rl_filename_dequoting_function           => ['F', 7],
       rl_char_is_quoted_p                      => ['F', 8],
       rl_ignore_some_completions_function      => ['F', 9],
       rl_directory_completion_hook             => ['F', 10],
       history_inhibit_expansion_function       => ['F', 11],
       rl_pre_input_hook                        => ['F', 12], # GRL 4.0
       rl_completion_display_matches_hook       => ['F', 13], # GRL 4.0
       rl_completion_word_break_hook            => ['F', 14], # GRL 5.0
       rl_prep_term_function                    => ['F', 15], # GRL 4.2
       rl_deprep_term_function                  => ['F', 16], # GRL 4.2
       rl_directory_rewrite_hook                => ['F', 17], # GRL 4.2
       rl_filename_rewrite_hook                 => ['F', 18], # GRL 6.1
       rl_signal_event_hook                     => ['F', 19], # GRL 6.3
       rl_input_available_hook                  => ['F', 20], # GRL 6.3
       rl_filename_stat_hook                    => ['F', 21], # GRL 6.3
       rl_timeout_event_hook                    => ['F', 22], # GRL 8.2

       rl_instream                              => ['IO', 0],
       rl_outstream                             => ['IO', 1],

       rl_executing_keymap                      => ['K', 0],
       rl_binding_keymap                        => ['K', 1],

       rl_last_func                             => ['LF', 0],
      );

my @stream;

sub TIESCALAR {
    my $class = shift;
    my $name = shift;
    return bless \$name, $class;
}

sub FETCH {
    my $self = shift;
    confess "wrong type" unless ref $self;

    my $name = $$self;
    if (! defined $_rl_vars{$name}) {
        confess "Term::ReadLine::Gnu::Var::FETCH: Unknown variable name `$name'\n";
        return undef ;
    }

    my ($type, $id) = @{$_rl_vars{$name}};
    if ($type eq 'S') {
        return _rl_fetch_str($id);
    } elsif ($type eq 'I') {
        return _rl_fetch_int($id);
    } elsif ($type eq 'C') {
        return chr(_rl_fetch_int($id));
    } elsif ($type eq 'F') {
        return _rl_fetch_function($id);
    } elsif ($type eq 'IO') {
        # STORE was called in new() before coming here
        return $stream[$id];
    } elsif ($type eq 'K') {
        return _rl_fetch_keymap($id);
    } elsif ($type eq 'LF') {
        return _rl_fetch_last_func();
    } else {
        carp "Term::ReadLine::Gnu::Var::FETCH: Illegal type `$type'\n";
        return undef;
    }
}

sub STORE {
    my $self = shift;
    confess "wrong type" unless ref $self;

    my $name = $$self;
    if (! defined $_rl_vars{$name}) {
        confess "Term::ReadLine::Gnu::Var::STORE: Unknown variable name `$name'\n";
        return undef ;
    }

    my $value = shift;
    my ($type, $id) = @{$_rl_vars{$name}};
    if ($type eq 'S') {
        if ($name eq 'rl_line_buffer') {
            return _rl_store_rl_line_buffer($value);
        } else {
            return _rl_store_str($value, $id);
        }
    } elsif ($type eq 'I') {
        return _rl_store_int($value, $id);
    } elsif ($type eq 'C') {
        return chr(_rl_store_int(ord($value), $id));
    } elsif ($type eq 'F') {
        return _rl_store_function($value, $id);
    } elsif ($type eq 'IO') {
        _rl_store_iostream($value, $id);
        # _rl_store_iostream() calls PerlIO_findFILE().  It pushes the
        # 'stdio' layer on perl 5.10 and later. We must pop the stdio
        # layer.
        #   https://rt.cpan.org/Ticket/Display.html?id=59832
        # But we must pop the 'stdio' layer only when utf8 layer is
        # included for remote debugging.
        #   https://rt.cpan.org/Ticket/Display.html?id=110121
        if ($] >= 5.010) {
            my @layers = PerlIO::get_layers($value);
            if ((grep /^utf8$/, @layers) > 0 && $layers[$#layers] eq 'stdio') {
                binmode($value,  ":pop");
            }
        }
        return $stream[$id] = $value;
    } elsif ($type eq 'K' || $type eq 'LF') {
        carp "Term::ReadLine::Gnu::Var::STORE: read only variable `$name'\n";
        return undef;
    } else {
        carp "Term::ReadLine::Gnu::Var::STORE: Illegal type `$type'\n";
        return undef;
    }
}

package Term::ReadLine::Gnu;
use Carp;
use strict;
use warnings;

#
#       set value of %Attribs
#

#       Tie all Readline/History variables
foreach (keys %Term::ReadLine::Gnu::Var::_rl_vars) {
    my $name;
    ($name = $_) =~ s/^rl_//;   # strip leading `rl_'
    tie $Attribs{$name},  'Term::ReadLine::Gnu::Var', $_;
}

#       add reference to some functions
{
    my ($name, $fname);
    no strict 'refs';           # allow symbolic reference
    map {
        ($name = $_) =~ s/^rl_//; # strip leading `rl_'
        $fname = 'Term::ReadLine::Gnu::XS::' . $_;
        $Attribs{$name} = \&$fname; # symbolic reference
    } qw(rl_getc
         rl_redisplay
         rl_callback_read_char
         rl_display_match_list
         rl_filename_completion_function
         rl_username_completion_function
         list_completion_function
         _trp_completion_function);
    # auto-splited subroutines cannot be processed in the map loop above
    use strict 'refs';
    $Attribs{shadow_redisplay} = \&Term::ReadLine::Gnu::XS::shadow_redisplay;
    $Attribs{Tk_getc} = \&Term::ReadLine::Gnu::XS::Tk_getc;
    $Attribs{list_completion_function} = \&Term::ReadLine::Gnu::XS::list_completion_function;
}

package Term::ReadLine::Gnu::AU;
use Carp;
no strict qw(refs vars);
use warnings;

sub AUTOLOAD {
    { $AUTOLOAD =~ s/.*:://; }  # preserve match data
    my $name;
    if (exists $Term::ReadLine::Gnu::XS::{"rl_$AUTOLOAD"}) {
        $name = "Term::ReadLine::Gnu::XS::rl_$AUTOLOAD";
    } elsif (exists $Term::ReadLine::Gnu::XS::{"$AUTOLOAD"}) {
        $name = "Term::ReadLine::Gnu::XS::$AUTOLOAD";
    } else {
        croak "Cannot do `$AUTOLOAD' in Term::ReadLine::Gnu";
    }
    no warnings 'redefine';     # Why is this line necessary ???
    *$AUTOLOAD = sub { shift; &$name(@_); };
    goto &$AUTOLOAD;
}
1;
__END__


=head2 C<Term::ReadLine::Gnu> Functions

All these GNU Readline/History Library functions supported are callable via
method interface and have names which conform to standard conventions
with the leading C<rl_> stripped.  For example C<rl_foo()>
function is called as C<$term-E<gt>foo()>.

The titles of the following sections are same as the titles of the
corresponding sections in the "Programming with GNU Readline" section
in the L<GNU Readline Library
Manual|https://tiswww.cwru.edu/php/chet/readline/readline.html>.
Refer them for further details.

Although it is preferred to use method interface, most methods have
lower level functions in
C<Term::ReadLine::Gnu::XS> package.  To use them a full qualified name
is required.

=head3 Basic Behavior

The function C<readline()> prints a prompt and then reads and returns
a single line of text from the user.

        $_ = $term->readline('Enter a line: ');

You can change key-bindings using C<bind_key(KEY, FUNCTION [,MAP])>
function.  The first argument, C<KEY>, is the character that you want
bind.  The second argument, C<FUNCTION>, is the function to call when
C<KEY> is pressed.  The C<FUNCTION> can be a reference to a Perl
function (see L</"Custom Functions">) or a "named function" named by
C<add_defun()> function or commands described in the "Bindable
Readline Commands" section in the L<GNU Readline Library
Manual|https://tiswww.cwru.edu/php/chet/readline/readline.html>.

        $term->bind_key(ord "\ci, 'tab-insert');

The above example binds Control-I to the 'tab-insert' command.

=head3 Custom Functions

You can write new functions using Perl.  The calling sequence for a
command foo looks like

        sub foo ($count, $key) { ... }

where C<$count> is the numeric argument (or 1 if defaulted) and
C<$key> is the key that invoked this function.

Here is an example;

        sub reverse_line {              # reverse a whole line
            my($count, $key) = @_;      # ignored in this sample function

            $t->modifying(0, $a->{end}); # save undo information
            $a->{line_buffer} = reverse $a->{line_buffer};
        }

See the "Writing a New Function" section in the L<GNU Readline Library
Manual|https://tiswww.cwru.edu/php/chet/readline/readline.html> for
further details.

=head3 Readline Convenience Functions

=head4 Naming a Function

=over 4

=item C<add_defun(NAME, FUNCTION [,KEY=-1])>

Add name to a Perl function C<FUNCTION>.  If optional argument C<KEY>
is specified, bind it to the C<FUNCTION>.  Returns reference to
C<FunctionPtr>.

  Example:
        # name `reverse-line' to a function reverse_line(),
        # and bind it to "\C-t"
        $term->add_defun('reverse-line', \&reverse_line, ord "\ct");

=back

=head4 Selecting a Keymap

=over 4

=item C<make_bare_keymap>

        Keymap  rl_make_bare_keymap()

=item C<copy_keymap(MAP)>

        Keymap  rl_copy_keymap(Keymap|str map)

=item C<make_keymap>

        Keymap  rl_make_keymap()

=item C<discard_keymap(MAP)>

        Keymap  rl_discard_keymap(Keymap|str map)

=item C<free_keymap(MAP)>

        void    rl_free_keymap(Keymap|str map)

=item C<empty_keymap(MAP)>

        int     rl_empty_keymap(Keymap|str map)                 # GRL 8.0

=item C<get_keymap>

        Keymap  rl_get_keymap()

=item C<set_keymap(MAP)>

        Keymap  rl_set_keymap(Keymap|str map)

=item C<get_keymap_by_name(NAME)>

        Keymap  rl_get_keymap_by_name(str name)

=item C<get_keymap_name(MAP)>

        str     rl_get_keymap_name(Keymap map)

=item C<set_keymap_name(NAME, MAP)>

        int     rl_set_keymap_name(str name, Keymap|str map)    # GRL 8.0

=back

=head4 Binding Keys

=over 4

=item C<bind_key(KEY, FUNCTION [,MAP])>

        int     rl_bind_key(int key, FunctionPtr|str function,
                            Keymap|str map = rl_get_keymap())

Bind C<KEY> to the C<FUNCTION>.  C<FUNCTION> is the name added by the
C<add_defun> method.  If optional argument C<MAP> is specified, binds
in C<MAP>.  Returns non-zero in case of error.

=item C<bind_key_if_unbound(KEY, FUNCTION [,MAP])>

        int     rl_bind_key_if_unbound(int key, FunctionPtr|str function,
                                       Keymap|str map = rl_get_keymap()) # GRL 5.0

=item C<unbind_key(KEY [,MAP])>

        int     rl_unbind_key(int key, Keymap|str map = rl_get_keymap())

Bind C<KEY> to the null function.  Returns non-zero in case of error.

=item C<unbind_function(FUNCTION [,MAP])>

        int     rl_unbind_function(FunctionPtr|str function,
                                   Keymap|str map = rl_get_keymap())

=item C<unbind_command(COMMAND [,MAP])>

        int     rl_unbind_command(str command,
                                  Keymap|str map = rl_get_keymap())

=item C<bind_keyseq(KEYSEQ, FUNCTION [,MAP])>

        int     rl_bind_keyseq(str keyseq, FunctionPtr|str function,
                               Keymap|str map = rl_get_keymap()) # GRL 5.0

=item C<set_key(KEYSEQ, FUNCTION [,MAP])>

        int     rl_set_key(str keyseq, FunctionPtr|str function,
                           Keymap|str map = rl_get_keymap())    # GRL 4.2

=item C<bind_keyseq_if_unbound(KEYSEQ, FUNCTION [,MAP])>

        int     rl_bind_keyseq_if_unbound(str keyseq, FunctionPtr|str function,
                                          Keymap|str map = rl_get_keymap()) # GRL 5.0

=item C<generic_bind(TYPE, KEYSEQ, DATA, [,MAP])>

        int     rl_generic_bind(int type, str keyseq,
                                FunctionPtr|Keymap|str data,
                                Keymap|str map = rl_get_keymap())

=item C<parse_and_bind(LINE)>

        void    rl_parse_and_bind(str line)

Parse C<LINE> as if it had been read from the F<~/.inputrc> file and
perform any key bindings and variable assignments found.  For further
detail see L<GNU Readline Library
Manual|https://tiswww.cwru.edu/php/chet/readline/readline.html>.

=item C<read_init_file([FILENAME])>

        int     rl_read_init_file(str filename = '~/.inputrc')

=back

=head4 Associating Function Names and Bindings

=over 4

=item C<named_function(NAME)>

        FunctionPtr rl_named_function(str name)

=item C<get_function_name(FUNCTION)>

        str     rl_get_function_name(FunctionPtr function)      # TRG original

=item C<function_of_keyseq(KEYSEQ [,MAP])>

        (FunctionPtr|Keymap|str data, int type)
                rl_function_of_keyseq(str keyseq,
                                      Keymap|str map = rl_get_keymap())

=item C<trim_arg_from_keyseq(KEYSEQ [,MAP])>

        int     rl_trim_arg_from_keyseq(str keyseq,
                                        Keymap|str map = rl_get_keymap()) # GRL 8.2

=item C<invoking_keyseqs(FUNCTION [,MAP])>

        (@str)  rl_invoking_keyseqs(FunctionPtr|str function,
                                    Keymap|str map = rl_get_keymap())

=item C<function_dumper([READABLE])>

        void    rl_function_dumper(int readable = 0)

=item C<list_funmap_names>

        void    rl_list_funmap_names()

=item C<funmap_names>

        (@str)  rl_funmap_names()

=item C<add_funmap_entry(NAME, FUNCTION)>

        int     rl_add_funmap_entry(char *name, FunctionPtr|str function)

=back

=head4 Allowing Undoing

=over 4

=item C<begin_undo_group>

        int     rl_begin_undo_group()

=item C<end_undo_group>

        int     rl_end_undo_group()

=item C<add_undo(WHAT, START, END, TEXT)>

        int     rl_add_undo(int what, int start, int end, str text)

=item C<free_undo_list>

        void    rl_free_undo_list()

=item C<do_undo>

        int     rl_do_undo()

=item C<modifying([START [,END]])>

        int     rl_modifying(int start = 0, int end = rl_end)

=back

=head4 Redisplay

=over 4

=item C<redisplay>

        void    rl_redisplay()

=item C<forced_update_display>

        int     rl_forced_update_display()

=item C<on_new_line>

        int     rl_on_new_line()

=item C<on_new_line_with_prompt>

        int     rl_on_new_line_with_prompt()                    # GRL 4.1

=item C<clear_visible_line()>

        int     rl_clear_visible_line()                         # GRL 7.0

=item C<reset_line_state>

        int     rl_reset_line_state()

=item C<crlf>

        int     rl_crlf()

=item C<show_char(C)>

        int     rl_show_char(int c)

=item C<message(FMT[, ...])>

        int     rl_message(str fmt, ...)

=item C<clear_message>

        int     rl_clear_message()

=item C<save_prompt>

        void    rl_save_prompt()

=item C<restore_prompt>

        void    rl_restore_prompt()

=item C<expand_prompt(PROMPT)>

        int     rl_expand_prompt(str prompt)

=item C<set_prompt(PROMPT)>

        int     rl_set_prompt(const str prompt)                 # GRL 4.2

=back

=head4 Modifying Text

=over 4

=item C<insert_text(TEXT)>

        int     rl_insert_text(str text)

=item C<delete_text([START [,END]])>

        int     rl_delete_text(int start = 0, int end = rl_end)

=item C<copy_text([START [,END]])>

        str     rl_copy_text(int start = 0, int end = rl_end)

=item C<kill_text([START [,END]])>

        int     rl_kill_text(int start = 0, int end = rl_end)

=item C<push_macro_input(MACRO)>

        int     rl_push_macro_input(str macro)

=back

=head4 Character Input

=over 4

=item C<read_key>

        int     rl_read_key()

=item C<getc(STREAM)>

        int     rl_getc(FILE *STREAM)

=item C<stuff_char(C)>

        int     rl_stuff_char(int c)

=item C<execute_next(C)>

        int     rl_execute_next(int c)

=item C<clear_pending_input()>

        int     rl_clear_pending_input()                        # GRL 4.2

=item C<set_keyboard_input_timeout(uSEC)>

        int     rl_set_keyboard_input_timeout(int usec)         # GRL 4.2

=item C<set_timeout(SECS, USECS)>

        int     rl_set_timeout(int secs, int usecs)             # GRL 8.2

=item C<clear_timeout()>

        int     rl_clear_timeout()                              # GRL 8.2

=item C<timeout_remaining()>

        int     rl_timeout_remaining()          # scalar context, GRL 8.2
        (int ret, int secs, int usecs)  rl_timeout_remaining()  # array context

=back

=head4 Terminal Management

=over 4

=item C<prep_terminal(META_FLAG)>

        void    rl_prep_terminal(int META_FLAG)

=item C<deprep_terminal()>

        void    rl_deprep_terminal()

=item C<tty_set_default_bindings([MAP])>

        void    rl_tty_set_default_bindings([Keymap|str map = rl_get_keymap()]) # GRL 4.0

=item C<tty_unset_default_bindings([MAP])>

        void    rl_tty_unset_default_bindings([Keymap|str map = rl_get_keymap()]) # GRL 5.0

=item C<tty_set_echoing(VALUE)>

        int     rl_tty_set_echoing(int value)                   # GRL 7.0

=item C<reset_terminal([TERMINAL_NAME])>

        int     rl_reset_terminal(str terminal_name = getenv($TERM))

=back

=head4 Utility Functions

=over 4

=item C<save_state(READLINE_STATE)>

        READLINE_STATE  rl_save_state()                         # GRL 6.0

=item C<restore_state(READLINE_STATE)>

        int     rl_restore_state(READLINE_STATE)                # GRL 6.0

=item C<free(MEM)>

        Not implemented since not required for Perl.
        int     rl_free(void *mem)                              # GRL 6.0

=item C<replace_line(TEXT [,CLEAR_UNDO])>

        int     rl_replace_line(str text, int clear_undo = 0)   # GRL 4.3

=item C<extend_line_buffer(LEN)>

        Not implemented since not required for Perl.
        int     rl_extend_line_buffer(int len)

=item C<initialize>

        int     rl_initialize()

=item C<ding>

        int     rl_ding()

=item C<alphabetic(C)>

        int     rl_alphabetic(int C)                            # GRL 4.2

=item C<display_match_list(MATCHES [,LEN [,MAX]])>

        void    rl_display_match_list(\@matches, len = $#maches, max) # GRL 4.0

Since the first element of an array C<@matches> as treated as a possible
completion, it is not displayed.  See the descriptions of
C<completion_matches()>.
When C<MAX> is omitted, the max length of an item in C<@matches> is used.

=back

=head4 Miscellaneous Functions

=over 4

=item C<macro_bind(KEYSEQ, MACRO [,MAP])>

        int     rl_macro_bind(const str keyseq, const str macro, Keymap map)

=item C<macro_dumper(READABLE)>

        int     rl_macro_dumper(int readline)

=item C<variable_bind(VARIABLE, VALUE)>

        int     rl_variable_bind(const str variable, const str value)

=item C<variable_value(VARIABLE)>

        str     rl_variable_value(const str variable)           # GRL 5.1

=item C<variable_dumper(READABLE)>

        int     rl_variable_dumper(int readline)

=item C<set_paren_blink_timeout(uSEC)>

        int     rl_set_paren_blink_timeout(usec)                # GRL 4.2

=item C<get_termcap(cap)>

        str     rl_get_termcap(cap)

=item C<clear_history>

        void    rl_clear_history()                              # GRL 6.3

=item C<activate_mark>

        void    rl_activate_mark()                              # GRL 8.1

=item C<deactivate_mark>

        void    rl_deactivate_mark()                            # GRL 8.1

=item C<keep_mark_active>

        void    rl_keep_mark_active()                           # GRL 8.1

=item C<mark_active_p>

        int     rl_mark_active_p()                              # GRL 8.1

=back

=head4 Alternate Interface

=over 4

=item C<callback_handler_install(PROMPT, LHANDLER)>

        void    rl_callback_handler_install(str prompt, pfunc lhandler)

=item C<callback_read_char>

        void    rl_callback_read_char()

=item C<callback_sigcleanup>                                    # GRL 7.0

        void    rl_callback_sigcleanup()

=item C<callback_handler_remove>

        void    rl_callback_handler_remove()

=back

=head3 Readline Signal Handling

=over 4

=item C<pending_signal()>

        int     rl_pending_signal()                             # GRL 7.0

=item C<cleanup_after_signal>

        void    rl_cleanup_after_signal()                       # GRL 4.0

=item C<free_line_state>

        void    rl_free_line_state()                            # GRL 4.0

=item C<reset_after_signal>

        void    rl_reset_after_signal()                         # GRL 4.0

=item C<check_signals>

        void    rl_check_signals()                              # GRL 8.0

=item C<echo_signal_char>

        void    rl_echo_signal_char(int sig)                    # GRL 6.0

=item C<resize_terminal>

        void    rl_resize_terminal()                            # GRL 4.0

=item C<set_screen_size(ROWS, COLS)>

        void    rl_set_screen_size(int ROWS, int COLS)          # GRL 4.2

=item C<get_screen_size()>

        (int rows, int cols)    rl_get_screen_size()            # GRL 4.2

=item C<reset_screen_size()>

        void    rl_reset_screen_size()                          # GRL 5.1

=item C<set_signals>

        int     rl_set_signals()                                # GRL 4.0

=item C<clear_signals>

        int     rl_clear_signals()                              # GRL 4.0

=back

=head3 Completion Functions

=over 4

=item C<complete_internal([WHAT_TO_DO])>

        int     rl_complete_internal(int what_to_do = TAB)

=item C<completion_mode(FUNCTION)>

        int     rl_completion_mode(FunctionPtr|str function)    # GRL 4.3

=item C<completion_matches(TEXT [,FUNC])>

        (@str)  rl_completion_matches(str text,
                                      pfunc func = filename_completion_function)

=item C<filename_completion_function(TEXT, STATE)>

        str     rl_filename_completion_function(str text, int state)

=item C<username_completion_function(TEXT, STATE)>

        str     rl_username_completion_function(str text, int state)

=item C<list_completion_function(TEXT, STATE)>

        str     list_completion_function(str text, int state)   # TRG original

=back

=head3 History Functions

=head4 Initializing History and State Management

=over 4

=item C<using_history>

        void    using_history()

=item C<history_get_history_state>

        HISTORY_STATE   history_get_hitory_state()              # GRL 6.3

=item C<history_set_history_state>

        void    history_set_hitory_state(HISTORY_STATE)         # GRL 6.3

=back

=head4 History List Management

=over 4

=item C<add_history(STRING)>

        void    add_history(str string)

=item C<add_history_time(STRING)>

        void    add_history_time(str string)                    # GRL 5.0

=item C<remove_history(WHICH)>

        str     remove_history(int which)

=item C<free_history(HISTENT)>

        Not implemented since Term::ReadLine::Gnu does not support the
        member 'data' of HIST_ENTRY structure. remove_history() frees
        the memory.
        histdata_t      free_history_entry(HIST_ENTRY *histent) # GRL 5.0

=item C<replace_history_entry(WHICH, STRING)>

        str     replace_history_entry(int which, str string)

=item C<clear_history>

        void    clear_history()

=item C<StifleHistory(MAX)>

        int     stifle_history(int max|undef)

stifles the history list, remembering only the last C<MAX> entries.
If C<MAX> is undef, remembers all entries.  This is a replacement
of C<unstifle_history()>.

=item C<unstifle_history>

        int     unstifle_history()

This is equivalent with C<stifle_history(undef)>.

=item C<history_is_stifled>

        int     history_is_stifled()

=item C<SetHistory(LINE1 [, LINE2, ...])>

sets the history of input, from where it can be used if the actual
C<readline> is present.

=back

=head4 Information About the History List

=over 4

=item C<history_list>

        Not implemented since not required for Perl.
        HIST_ENTRY **history_list()

=item C<where_history>

        int     where_history()

=item C<current_history>

        str     current_history()

=item C<history_get(OFFSET)>

        str     history_get(offset)

=item C<history_get_time(OFFSET)>

        time_t  history_get_time(offset)                        # GRL 5.0

=item C<history_total_bytes>

        int     history_total_bytes()

=item C<GetHistory>

returns the history of input as a list, if actual C<readline> is present.

=back

=head4 Moving Around the History List

=over 4

=item C<history_set_pos(POS)>

        int     history_set_pos(int pos)

=item C<previous_history>

        str     previous_history()

=item C<next_history>

        str     next_history()

=back

=head4 Searching the History List

=over 4

=item C<history_search(STRING [,DIRECTION])>

        int     history_search(str string, int direction = -1)

=item C<history_search_prefix(STRING [,DIRECTION])>

        int     history_search_prefix(str string, int direction = -1)

=item C<history_search_pos(STRING [,DIRECTION [,POS]])>

        int     history_search_pos(str string,
                                   int direction = -1,
                                   int pos = where_history())

=back

=head4 Managing the History File

=over 4

=item C<ReadHistory([FILENAME [,FROM [,TO]]])>

        int     read_history(str filename = '~/.history',
                             int from = 0, int to = -1)

        int     read_history_range(str filename = '~/.history',
                                   int from = 0, int to = -1)

adds the contents of C<FILENAME> to the history list, a line at a
time.  If C<FILENAME> is false, then read from F<~/.history>.  Start
reading at line C<FROM> and end at C<TO>.  If C<FROM> is omitted or
zero, start at the beginning.  If C<TO> is omitted or less than
C<FROM>, then read until the end of the file.  Returns true if
successful, or false if not.  C<read_history()> is an alias of
C<read_history_range()>.

=item C<WriteHistory([FILENAME])>

        int     write_history(str filename = '~/.history')

writes the current history to C<FILENAME>, overwriting C<FILENAME> if
necessary.  If C<FILENAME> is false, then write the history list to
F<~/.history>.  Returns true if successful, or false if not.


=item C<append_history(NELEMENTS [,FILENAME])>

        int     append_history(int nelements, str filename = '~/.history')

=item C<history_truncate_file([FILENAME [,NLINES]])>

        int     history_truncate_file(str filename = '~/.history',
                                      int nlines = 0)

=back

=head4 History Expansion

=over 4

=item C<history_expand(STRING)>

        (int result, str expansion) history_expand(str string)

Note that this function returns C<expansion> in the scalar context.

=item C<get_history_event(STRING, CINDEX [,QCHAR])>

        (str text, int cindex) = get_history_event(str  string,
                                                   int  cindex,
                                                   char qchar = '\0')

=item C<history_tokenize(STRING)>

        (@str)  history_tokenize(str string)

=item C<history_arg_extract(STRING, [FIRST [,LAST]])>

        str history_arg_extract(str string, int first = 0, int last = '$')

=back

=head2 C<Term::ReadLine::Gnu> Variables

Following GNU Readline/History Library variables can be accessed by a
Perl program.  See L<GNU Readline Library
Manual|https://tiswww.cwru.edu/php/chet/readline/readline.html> and
L<GNU History Library
Manual|https://tiswww.cwru.edu/php/chet/readline/history.html> for
details of each variable.  You can access them by using C<Attribs>
methods.  Names of keys in this hash conform to standard conventions
with the leading C<rl_> stripped.

Examples:

    $attribs = $term->Attribs;
    $v = $attribs->{library_version};   # rl_library_version
    $v = $attribs->{history_base};      # history_base

=head3 Readline Variables

        str rl_line_buffer
        int rl_point
        int rl_end
        int rl_mark
        int rl_done
        int rl_eof_found (GRL 8.2)
        int rl_num_chars_to_read (GRL 4.1)
        int rl_pending_input
        int rl_dispatching
        int rl_erase_empty_line (GRL 4.0)
        str rl_prompt (read only)
        str rl_display_prompt
        int rl_already_prompted (GRL 4.1)
        str rl_library_version (read only)
        int rl_readline_version (read only)
        int rl_gnu_readline_p (GRL 4.1, read only)
        str rl_terminal_name
        str rl_readline_name
        filehandle rl_instream
        filehandle rl_outstream
        int rl_prefer_env_winsize (GRL 5.1)
        pfunc rl_last_func (GRL 4.2, read only)
        pfunc rl_startup_hook
        pfunc rl_pre_input_hook (GRL 4.0)
        pfunc rl_event_hook
        pfunc rl_getc_function
        pfunc rl_signal_event_hook (GRL 6.3)
        pfunc rl_timeout_event_hook (GRL 8.2)
        pfunc rl_input_available_hook (GRL 6.3)
        pfunc rl_redisplay_function
        pfunc rl_prep_term_function (GRL 2.1)
        pfunc rl_deprep_term_function (GRL 2.1)
        Keymap rl_executing_keymap (read only)
        Keymap rl_binding_keymap (read only)
        str rl_executing_macro (GRL 4.2, read only)
        int rl_executing_key (GRL 6.3, read only)
        str rl_executing_keyseq (GRL 6.3, read only)
        int rl_key_sequence_length (read only)
        int rl_readline_state (GRL 4.2)
        int rl_explicit_arg (read only)
        int rl_numeric_arg (read only)
        int rl_editing_mode (read only)

=head3 Signal Handling Variables

        int rl_catch_signals (GRL 4.0)
        int rl_catch_sigwinch (GRL 4.0)
        int rl_persistent_signal_handlers (GRL 7.0)
        int rl_change_environment (GRL 6.3)

=head3 Completion Variables

        pfunc rl_completion_entry_function
        pfunc rl_attempted_completion_function
        pfunc rl_filename_quoting_function
        pfunc rl_filename_dequoting_function
        pfunc rl_char_is_quoted_p
        pfunc rl_ignore_some_completions_function
        pfunc rl_directory_completion_hook
        pfunc rl_directory_rewrite_hook (GRL 4.2)
        pfunc rl_filename_stat_hook (GRL 6.3)
        pfunc rl_filename_rewrite_hook (GRL 6.1)
        pfunc rl_completion_display_matches_hook (GRL 4.0)
        str rl_basic_word_break_characters
        str rl_basic_quote_characters
        str rl_completer_word_break_characters
        pfunc rl_completion_word_break_hook (GRL 5.0)
        str rl_completer_quote_characters
        str rl_filename_quote_characters
        str rl_special_prefixes
        int rl_completion_query_items
        int rl_completion_append_character
        int rl_completion_suppress_append (GRL 4.3)
        int rl_completion_quote_character (GRL 5.0, read only)
        int rl_completion_suppress_quote (GRL 5.0)
        int rl_completion_found_quote (GRL 5.0, read only)
        int rl_completion_mark_symlink_dirs (GRL 4.3)
        int rl_ignore_completion_duplicates
        int rl_filename_completion_desired
        int rl_filename_quoting_desired
        int rl_attempted_completion_over
        int rl_sort_completion_matches (GRL 6.0)
        int rl_completion_type (read only)
        int rl_completion_invoking_key (GRL 6.0, read only)
        int rl_inhibit_completion

=head3 History Variables

        int history_base
        int history_length
        int history_max_entries (called `max_input_history', read only)
        int history_write_timestamps (GRL 5.0)
        char history_expansion_char
        char history_subst_char
        char history_comment_char
        str history_word_delimiters (GRL 4.2)
        str history_search_delimiter_chars
        str history_no_expand_chars
        int history_quotes_inhibit_expansion
        int history_quoting_state
        pfunc history_inhibit_expansion_function

=head3 Function References

        rl_getc
        rl_redisplay
        rl_callback_read_char
        rl_display_match_list
        rl_filename_completion_function
        rl_username_completion_function
        list_completion_function
        shadow_redisplay
        Tk_getc

=head2 Custom Completion

In this section variables and functions for custom completion are
described along with examples.

Most of descriptions in this section came from L<GNU Readline
Library
Manual|https://tiswww.cwru.edu/php/chet/readline/readline.html>.

=over 4

=item C<completion_entry_function>

This variable holds reference refers to a generator function for
C<completion_matches()>.

A generator function is called repeatedly from
C<completion_matches()>, returning a string each time.  The arguments
to the generator function are C<TEXT> and C<STATE>.  C<TEXT> is the
partial word to be completed.  C<STATE> is zero the first time the
function is called, allowing the generator to perform any necessary
initialization, and a positive non-zero integer for each subsequent
call.  When the generator function returns C<undef> this signals
C<completion_matches()> that there are no more possibilities left.

If this variable set to undef, built-in C<filename_completion_function> is
used.

A sample generator function, C<list_completion_function>, is defined
in Gnu.pm.  You can use it as follows;

    use Term::ReadLine;
    ...
    my $term = new Term::ReadLine 'sample';
    my $attribs = $term->Attribs;
    ...
    $attribs->{completion_entry_function} =
        $attribs->{list_completion_function};
    ...
    $attribs->{completion_word} =
        [qw(reference to a list of words which you want to use for completion)];
    $term->readline("custom completion>");

See also C<completion_matches>.

=item C<attempted_completion_function>

A reference to an alternative function to create matches.

The function is called with C<TEXT>, C<LINE_BUFFER>, C<START>, and
C<END>.  C<LINE_BUFFER> is a current input buffer string.  C<START>
and C<END> are indices in C<LINE_BUFFER> saying what the boundaries of
C<TEXT> are.

If this function exists and returns null list or C<undef>, or if this
variable is set to C<undef>, then an internal function
C<rl_complete()> will call the value of
C<completion_entry_function> to generate matches, otherwise the
array of strings returned will be used.

The default value of this variable is C<undef>.  You can use it as follows;

    use Term::ReadLine;
    ...
    my $term = new Term::ReadLine 'sample';
    my $attribs = $term->Attribs;
    ...
    sub sample_completion {
        my ($text, $line, $start, $end) = @_;
        # If first word then username completion, else filename completion
        if (substr($line, 0, $start) =~ /^\s*$/) {
            return $term->completion_matches($text,
                                             $attribs->{'username_completion_function'});
        } else {
            return ();
        }
    }
    ...
    $attribs->{attempted_completion_function} = \&sample_completion;

=item C<completion_matches(TEXT, ENTRY_FUNC)>

Returns an array of strings which is a list of completions for
C<TEXT>.  If there are no completions, returns C<undef>.  The first
entry in the returned array is the substitution for C<TEXT>.  The
remaining entries are the possible completions.

C<ENTRY_FUNC> is a generator function which has two arguments, and
returns a string.  The first argument is C<TEXT>.  The second is a
state argument; it is zero on the first call, and non-zero on
subsequent calls.  C<ENTRY_FUNC> returns C<undef> to the caller when
there are no more matches.

If the value of C<ENTRY_FUNC> is undef, built-in
C<filename_completion_function> is used.

C<completion_matches> is a Perl wrapper function of an internal
function C<completion_matches()>.  See also
C<completion_entry_function>.

=item C<completion_function>

A variable whose content is a reference to a function which returns a
list of candidates to complete.

This variable is compatible with L<Term::ReadLine::Perl|http://search.cpan.org/dist/Term-ReadLine-Perl/> and very easy
to use.

    use Term::ReadLine;
    ...
    my $term = new Term::ReadLine 'sample';
    my $attribs = $term->Attribs;
    ...
    $attribs->{completion_function} = sub {
        my ($text, $line, $start) = @_;
        return qw(a list of candidates to complete);
    };

=item C<list_completion_function(TEXT, STATE)>

A sample generator function defined by C<Term::ReadLine::Gnu>.
Example code at C<completion_entry_function> shows how to use this
function.

=back

=head2 C<Term::ReadLine::Gnu> Specific Features

=head3 C<Term::ReadLine::Gnu> Specific Functions

=over 4

=item C<CallbackHandlerInstall(PROMPT, LHANDLER)>

This method provides the function C<rl_callback_handler_install()>
with the following additional feature compatible with C<readline>
method; ornament feature, L<Term::ReadLine::Perl|http://search.cpan.org/dist/Term-ReadLine-Perl/> compatible
completion function, history expansion, and addition to history
buffer.

=item C<call_function(FUNCTION, [COUNT [,KEY]])>

        int     rl_call_function(FunctionPtr|str function, count = 1, key = -1)

=item C<get_all_function_names>

Returns a list of all function names.

=item C<shadow_redisplay>

A redisplay function for password input.  You can use it as follows;

        $attribs->{redisplay_function} = $attribs->{shadow_redisplay};
        $line = $term->readline("password> ");

=item C<filename_list>

Returns candidates of filenames to complete.  This function can be used
with C<completion_function> and is implemented for the compatibility
with L<Term::ReadLine::Perl|http://search.cpan.org/dist/Term-ReadLine-Perl/>.

=item C<list_completion_function>

See the description of section L<"Custom Completion"|"Custom Completion">.

=back

=head3 C<Term::ReadLine::Gnu> Specific Variables

=over 4

=item C<do_expand>

When true, the history expansion is enabled.  By default false.

=item C<completion_function>

See the description of section L<"Custom Completion"|"Custom Completion">.

=item C<completion_word>

A reference to a list of candidates to complete for
C<list_completion_function>.

=back

=head3 C<Term::ReadLine::Gnu> Specific Commands

=over 4

=item C<history-expand-line>

The equivalent of the Bash C<history-expand-line> editing command.

=item C<operate-and-get-next>

The equivalent of the Korn shell C<operate-and-get-next-history-line>
editing command and the Bash C<operate-and-get-next>.

This command is bound to C<\C-o> by default for the compatibility with
the Bash and L<Term::ReadLine::Perl|http://search.cpan.org/dist/Term-ReadLine-Perl/>.

=item C<display-readline-version>

Shows the version of C<Term::ReadLine::Gnu> and the one of the GNU
Readline Library.

=item C<change-ornaments>

Change ornaments interactively.

=back

=head1 FILES

=over 4

=item F<~/.inputrc>

Readline init file.  Using this file it is possible that you would
like to use a different set of key bindings.  When a program which
uses the GNU Readline library starts up, the init file is read, and
the key bindings are set.

The conditional init constructs is supported.  The program name which is
specified by the first argument of C<new> method is used as the
application construct.

For example, when your program calls C<new> method as follows;

        ...
        $term = new Term::ReadLine 'PerlSh';
        ...

your F<~/.inputrc> can define key bindings only for the program as
follows;

        ...
        $if PerlSh
        Meta-Rubout: backward-kill-word
        "\C-x\C-r": re-read-init-file
        "\e[11~": "Function Key 1"
        $endif
        ...

For further details, see the section "Readline Init File" in the L<GNU
Readline Library
Manual|https://tiswww.cwru.edu/php/chet/readline/readline.html>

=back

=head1 EXPORTS

No symbols are exported by default.
The following tags are defined and their symbols can be exported.

=over 4

=item prompt

RL_PROMPT_START_IGNORE RL_PROMPT_END_IGNORE

=item match_type

NO_MATCH SINGLE_MATCH MULT_MATCH

=item keymap_type

ISFUNC ISKMAP ISMACR

=item undo_code

UNDO_DELETE UNDO_INSERT UNDO_BEGIN UNDO_END

=item rl_state

RL_STATE_NONE RL_STATE_INITIALIZING
RL_STATE_INITIALIZED RL_STATE_TERMPREPPED
RL_STATE_READCMD RL_STATE_METANEXT
RL_STATE_DISPATCHING RL_STATE_MOREINPUT
RL_STATE_ISEARCH RL_STATE_NSEARCH
RL_STATE_SEARCH RL_STATE_NUMERICARG
RL_STATE_MACROINPUT RL_STATE_MACRODEF
RL_STATE_OVERWRITE RL_STATE_COMPLETING
RL_STATE_SIGHANDLER RL_STATE_UNDOING
RL_STATE_INPUTPENDING RL_STATE_TTYCSAVED
RL_STATE_CALLBACK RL_STATE_VIMOTION
RL_STATE_MULTIKEY RL_STATE_VICMDONCE
RL_STATE_CHARSEARCH RL_STATE_REDISPLAYING
RL_STATE_DONE RL_STATE_TIMEOUT
RL_STATE_EOF

=back

They can be exported as follows;

        use Term::ReadLine;
        BEGIN {
            import Term::ReadLine::Gnu qw(:keymap_type RL_STATE_INITIALIZED);
        }

=head1 ENVIRONMENT

The environment variable C<PERL_RL> governs which ReadLine clone is
loaded.  See the ENVIRONMENT section on
L<Term::ReadLine|http://search.cpan.org/dist/Term-ReadLine/> for
further details.

If the environment variable C<TERM> is set to C<"emacs">
or the environment variable C<INSIDE_EMACS> or C<EMACS> is defined,
C<Term::ReadLine::Stub> is used instead of <Term::ReadLine:Gnu>.

=head1 SEE ALSO

=over 4

=item L<Term::ReadLine::Gnu Project Home Page|https://github.com/hirooih/perl-trg>

=item L<GNU Readline Library Manual|https://tiswww.cwru.edu/php/chet/readline/readline.html>

=item L<GNU History Library Manual|https://tiswww.cwru.edu/php/chet/readline/history.html>

=item Sample and test programs (F<eg/*> and F<t/*>) in L<the C<Term::ReadLine::Gnu> distribution|http://search.cpan.org/dist/Term-ReadLine-Gnu/>

=item L<Term::ReadLine|http://search.cpan.org/dist/Term-ReadLine/>

=item Works which use Term::ReadLine::Gnu

=over 4

=item Distributions which depend on Term::ReadLine::Gnu on L<CPAN|http://www.cpan.org/>

L<https://metacpan.org/requires/distribution/Term-ReadLine-Gnu>

=item L<Perl Debugger|http://perldoc.perl.org/perldebug.html>

        perl -d

=item L<Perl Shell (psh)|http://gnp.github.io/psh/>

The Perl Shell is a shell that combines the interactive nature of a
Unix shell with the power of Perl.

A programmable completion feature compatible with bash is implemented.

=item L<SPP (Synopsys Plus Perl)|http://vlsiweb.stanford.edu/~jsolomon/SPP/>

SPP (Synopsys Plus Perl) is a Perl module that wraps around Synopsys'
shell programs.  SPP is inspired by the original dc_perl written by
Steve Golson, but it's an entirely new implementation.  Why is it
called SPP and not dc_perl?  Well, SPP was written to wrap around any
of Synopsys' shells.

=item L<PFM (Personal File Manager for UnixE<sol>Linux)|http://p-f-m.sourceforge.net/>

Pfm is a terminal-based file manager written in Perl, based on PFM.COM
for MS-DOS (originally by Paul Culley and Henk de Heer).

=item L<The soundgrab|https://sourceforge.net/projects/soundgrab/>

soundgrab is designed to help you slice up a big long raw audio file
(by default 44.1 kHz 2 channel signed sixteen bit little endian) and
save your favorite sections to other files. It does this by providing
you with a cassette player like command line interface.

=item L<PDL (The Perl Data Language)|http://pdl.perl.org/>

PDL (``Perl Data Language'') gives standard Perl the ability to
compactly store and speedily manipulate the large N-dimensional data
arrays which are the bread and butter of scientific computing.

=item L<PIQT (Perl Interactive DBI Query Tool)|http://piqt.sourceforge.net/>

PIQT is an interactive query tool using the Perl DBI database
interface. It supports ReadLine, provides a built in scripting language
with a Lisp like syntax, an online help system, and uses wrappers to
interface to the DBD modules.

=item L<vshnu (the New Visual Shell)|http://www.cs.indiana.edu/~kinzler/vshnu/>

A visual shell and CLI shell supplement.

=back

If you know any other works you recommend, please let me know.

=back

=head1 AUTHOR

Hiroo Hayashi C<E<lt>hiroo.hayashi@computer.orgE<gt>>

L<http://search.cpan.org/~hayashi/>

=head1 TODO

GTK+ support in addition to Tk.

=head1 BUGS

=over 4

=item Submit a bug report to
L<the bug tracker on GitHub|https://github.com/hirooih/perl-trg/issues>.

=item C<add_defun()> can define up to 16 functions.

=item Some functions and variables do not have test code yet.  Your
contribution is welcome.  See F<t/readline.t> for details.

=item If the pager command (| or ||) in Perl debugger causes segmentation
fault, you need to fix F<perl5db.pl>.  See
L<https://rt.perl.org/Public/Bug/Display.html?id=121456> for details.

=back

=head1 LICENSE

Copyright (c) 1996-2020 Hiroo Hayashi.  All rights reserved.

This program is free software; you can redistribute it and/or modify
it under the same terms as Perl itself.

=cut
