[p5sagit/p5-mst-13.2.git] / lib / Term / ReadLine.pm

=head1 NAME

Term::ReadLine - Perl interface to various C<readline> packages. If
no real package is found, substitutes stubs instead of basic functions.

=head1 SYNOPSIS

  use Term::ReadLine;
  $term = new Term::ReadLine 'Simple Perl calc';
  $prompt = "Enter your arithmetic expression: ";
  $OUT = $term->OUT || STDOUT;
  while ( defined ($_ = $term->readline($prompt)) ) {
    $res = eval($_), "\n";
    warn $@ if $@;
    print $OUT $res, "\n" unless $@;
    $term->addhistory($_) if /\S/;
  }

=head1 DESCRIPTION

This package is just a front end to some other packages. At the moment
this description is written, the only such package is Term-ReadLine,
available on CPAN near you. The real target of this stub package is to
set up a common interface to whatever Readline emerges with time.

=head1 Minimal set of supported functions

All the supported functions should be called as methods, i.e., either as 

  $term = new Term::ReadLine 'name';

or as 

  $term->addhistory('row');

where $term is a return value of Term::ReadLine-E<gt>Init.

=over 12

=item C<ReadLine>

returns the actual package that executes the commands. Among possible
values are C<Term::ReadLine::Gnu>, C<Term::ReadLine::Perl>,
C<Term::ReadLine::Stub Exporter>.

=item C<new>

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> filehandles. These
arguments should be globs.

=item C<readline>

gets an input line, I<possibly> with actual C<readline>
support. Trailing newline is removed. Returns C<undef> on C<EOF>.

=item C<addhistory>

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

=item C<IN>, $C<OUT>

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

=item C<MinLine>

If argument 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.

=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">.

=item Attribs

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

=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.

If C<Features> method reports a feature C<attribs> as present, the
method C<Attribs> is not dummy.

=back

=head1 Additional supported functions

Actually C<Term::ReadLine> can use some other package, that will
support reacher set of commands.

All these commands are callable via method interface and have names
which conform to standard conventions with the leading C<rl_> stripped.

The stub package included with the perl distribution allows some
additional methods: 

=over 12

=item C<tkRunning>

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

=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.

=item C<newTTY>

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

=back

One can check whether the currently loaded ReadLine package supports
these methods by checking for corresponding C<Features>.

=head1 EXPORTS

None

=head1 ENVIRONMENT

The variable C<PERL_RL> governs which ReadLine clone is loaded. If the
value is false, a dummy interface is used. If the value is true, it
should be tail of the name of the package to use, such as C<Perl> or
C<Gnu>. 

If the variable is not set, the best available package is loaded.

=cut

package Term::ReadLine::Stub;
@ISA = qw'Term::ReadLine::Tk Term::ReadLine::TermCap';

$DB::emacs = $DB::emacs;	# To peacify -w
*rl_term_set = \@Term::ReadLine::TermCap::rl_term_set;

sub ReadLine {'Term::ReadLine::Stub'}
sub readline {
  my $self = shift;
  my ($in,$out,$str) = @$self;
  print $out $rl_term_set[0], shift, $rl_term_set[1], $rl_term_set[2]; 
  $self->register_Tk 
     if not $Term::ReadLine::registered and $Term::ReadLine::toloop
	and defined &Tk::DoOneEvent;
  #$str = scalar <$in>;
  $str = $self->get_line;
  print $out $rl_term_set[3]; 
  # bug in 5.000: chomping empty string creats length -1:
  chomp $str if defined $str;
  $str;
}
sub addhistory {}

sub findConsole {
    my $console;

    if (-e "/dev/tty") {
	$console = "/dev/tty";
    } elsif (-e "con" or $^O eq 'MSWin32') {
	$console = "con";
    } else {
	$console = "sys\$command";
    }

    if ($^O eq 'amigaos') {
	$console = undef;
    }
    elsif ($^O eq 'os2') {
      if ($DB::emacs) {
	$console = undef;
      } else {
	$console = "/dev/con";
      }
    }

    $consoleOUT = $console;
    $console = "&STDIN" unless defined $console;
    if (!defined $consoleOUT) {
      $consoleOUT = defined fileno(STDERR) ? "&STDERR" : "&STDOUT";
    }
    ($console,$consoleOUT);
}

sub new {
  die "method new called with wrong number of arguments" 
    unless @_==2 or @_==4;
  #local (*FIN, *FOUT);
  my ($FIN, $FOUT);
  if (@_==2) {
    ($console, $consoleOUT) = findConsole;

    open(FIN, "<$console"); 
    open(FOUT,">$consoleOUT");
    #OUT->autoflush(1);		# Conflicts with debugger?
    $sel = select(FOUT);
    $| = 1;				# for DB::OUT
    select($sel);
    bless [\*FIN, \*FOUT];
  } else {			# Filehandles supplied
    $FIN = $_[2]; $FOUT = $_[3];
    #OUT->autoflush(1);		# Conflicts with debugger?
    $sel = select($FOUT);
    $| = 1;				# for DB::OUT
    select($sel);
    bless [$FIN, $FOUT];
  }
}

sub newTTY {
  my ($self, $in, $out) = @_;
  $self->[0] = $in;
  $self->[1] = $out;
  my $sel = select($out);
  $| = 1;				# for DB::OUT
  select($sel);
}

sub IN { shift->[0] }
sub OUT { shift->[1] }
sub MinLine { undef }
sub Attribs { {} }

my %features = (tkRunning => 1, ornaments => 1, 'newTTY' => 1);
sub Features { \%features }

package Term::ReadLine;		# So late to allow the above code be defined?

my $which = $ENV{PERL_RL};
if ($which) {
  if ($which =~ /\bgnu\b/i){
    eval "use Term::ReadLine::Gnu;";
  } elsif ($which =~ /\bperl\b/i) {
    eval "use Term::ReadLine::Perl;";
  } else {
    eval "use Term::ReadLine::$which;";
  }
} elsif (defined $which) {	# Defined but false
  # Do nothing fancy
} else {
  eval "use Term::ReadLine::Gnu; 1" or eval "use Term::ReadLine::Perl; 1";
}

#require FileHandle;

# To make possible switch off RL in debugger: (Not needed, work done
# in debugger).

if (defined &Term::ReadLine::Gnu::readline) {
  @ISA = qw(Term::ReadLine::Gnu Term::ReadLine::Stub);
} elsif (defined &Term::ReadLine::Perl::readline) {
  @ISA = qw(Term::ReadLine::Perl Term::ReadLine::Stub);
} else {
  @ISA = qw(Term::ReadLine::Stub);
}

package Term::ReadLine::TermCap;

# Prompt-start, prompt-end, command-line-start, command-line-end
#     -- zero-width beautifies to emit around prompt and the command line.
@rl_term_set = ("","","","");
# string encoded:
$rl_term_set = ',,,';

sub LoadTermCap {
  return if defined $terminal;
  
  require Term::Cap;
  $terminal = Tgetent Term::Cap ({OSPEED => 9600}); # Avoid warning.
}

sub ornaments {
  shift;
  return $rl_term_set unless @_;
  $rl_term_set = shift;
  $rl_term_set ||= ',,,';
  $rl_term_set = 'us,ue,md,me' if $rl_term_set == 1;
  my @ts = split /,/, $rl_term_set, 4;
  eval { LoadTermCap };
  warn("Cannot find termcap: $@\n"), return unless defined $terminal;
  @rl_term_set = map {$_ ? $terminal->Tputs($_,1) || '' : ''} @ts;
  return $rl_term_set;
}


package Term::ReadLine::Tk;

$count_handle = $count_DoOne = $count_loop = 0;

sub handle {$giveup = 1; $count_handle++}

sub Tk_loop {
  # Tk->tkwait('variable',\$giveup);	# needs Widget
  $count_DoOne++, Tk::DoOneEvent(0) until $giveup;
  $count_loop++;
  $giveup = 0;
}

sub register_Tk {
  my $self = shift;
  $Term::ReadLine::registered++ 
    or Tk->fileevent($self->IN,'readable',\&handle);
}

sub tkRunning {
  $Term::ReadLine::toloop = $_[1] if @_ > 1;
  $Term::ReadLine::toloop;
}

sub get_c {
  my $self = shift;
  $self->Tk_loop if $Term::ReadLine::toloop && defined &Tk::DoOneEvent;
  return getc $self->IN;
}

sub get_line {
  my $self = shift;
  $self->Tk_loop if $Term::ReadLine::toloop && defined &Tk::DoOneEvent;
  my $in = $self->IN;
  return scalar <$in>;
}

1;
Commit	Line	Data
cb31d310	1	=head1 NAME
cb31d310	2
c07a80fd	3	Term::ReadLine - Perl interface to various C<readline> packages. If
cb31d310	4	no real package is found, substitutes stubs instead of basic functions.
	5
	6	=head1 SYNOPSIS
	7
	8	use Term::ReadLine;
	9	$term = new Term::ReadLine 'Simple Perl calc';
	10	$prompt = "Enter your arithmetic expression: ";
	11	$OUT = $term->OUT \|\| STDOUT;
	12	while ( defined ($_ = $term->readline($prompt)) ) {
	13	$res = eval($_), "\n";
	14	warn $@ if $@;
	15	print $OUT $res, "\n" unless $@;
	16	$term->addhistory($_) if /\S/;
	17	}
	18
c07a80fd	19	=head1 DESCRIPTION
	20
	21	This package is just a front end to some other packages. At the moment
	22	this description is written, the only such package is Term-ReadLine,
	23	available on CPAN near you. The real target of this stub package is to
	24	set up a common interface to whatever Readline emerges with time.
	25
cb31d310	26	=head1 Minimal set of supported functions
	27
	28	All the supported functions should be called as methods, i.e., either as
	29
	30	$term = new Term::ReadLine 'name';
	31
	32	or as
	33
	34	$term->addhistory('row');
	35
1fef88e7	36	where $term is a return value of Term::ReadLine-E<gt>Init.
cb31d310	37
	38	=over 12
	39
	40	=item C<ReadLine>
	41
	42	returns the actual package that executes the commands. Among possible
	43	values are C<Term::ReadLine::Gnu>, C<Term::ReadLine::Perl>,
	44	C<Term::ReadLine::Stub Exporter>.
	45
	46	=item C<new>
	47
	48	returns the handle for subsequent calls to following
	49	functions. Argument is the name of the application. Optionally can be
	50	followed by two arguments for C<IN> and C<OUT> filehandles. These
	51	arguments should be globs.
	52
	53	=item C<readline>
	54
	55	gets an input line, I<possibly> with actual C<readline>
	56	support. Trailing newline is removed. Returns C<undef> on C<EOF>.
	57
	58	=item C<addhistory>
	59
	60	adds the line to the history of input, from where it can be used if
	61	the actual C<readline> is present.
	62
	63	=item C<IN>, $C<OUT>
	64
	65	return the filehandles for input and output or C<undef> if C<readline>
	66	input and output cannot be used for Perl.
	67
	68	=item C<MinLine>
	69
	70	If argument is specified, it is an advice on minimal size of line to
	71	be included into history. C<undef> means do not include anything into
	72	history. Returns the old value.
	73
	74	=item C<findConsole>
	75
	76	returns an array with two strings that give most appropriate names for
1fef88e7	77	files for input and output using conventions C<"E<lt>$in">, C<"E<gt>out">.
cb31d310	78
a737e074	79	=item Attribs
	80
	81	returns a reference to a hash which describes internal configuration
	82	of the package. Names of keys in this hash conform to standard
	83	conventions with the leading C<rl_> stripped.
	84
cb31d310	85	=item C<Features>
	86
	87	Returns a reference to a hash with keys being features present in
	88	current implementation. Several optional features are used in the
	89	minimal interface: C<appname> should be present if the first argument
	90	to C<new> is recognized, and C<minline> should be present if
	91	C<MinLine> method is not dummy. C<autohistory> should be present if
	92	lines are put into history automatically (maybe subject to
	93	C<MinLine>), and C<addhistory> if C<addhistory> method is not dummy.
	94
a737e074	95	If C<Features> method reports a feature C<attribs> as present, the
	96	method C<Attribs> is not dummy.
	97
cb31d310	98	=back
cb31d310	99
a737e074	100	=head1 Additional supported functions
a737e074	101
cb31d310	102	Actually C<Term::ReadLine> can use some other package, that will
	103	support reacher set of commands.
	104
a737e074	105	All these commands are callable via method interface and have names
	106	which conform to standard conventions with the leading C<rl_> stripped.
	107
f36776d9	108	The stub package included with the perl distribution allows some
	109	additional methods:
	110
	111	=over 12
	112
	113	=item C<tkRunning>
	114
7a2e2cd6	115	makes Tk event loop run when waiting for user input (i.e., during
f36776d9	116	C<readline> method).
	117
	118	=item C<ornaments>
	119
	120	makes the command line stand out by using termcap data. The argument
	121	to C<ornaments> should be 0, 1, or a string of a form
	122	C<"aa,bb,cc,dd">. Four components of this string should be names of
	123	I<terminal capacities>, first two will be issued to make the prompt
	124	standout, last two to make the input line standout.
	125
	126	=item C<newTTY>
	127
	128	takes two arguments which are input filehandle and output filehandle.
	129	Switches to use these filehandles.
	130
	131	=back
	132
	133	One can check whether the currently loaded ReadLine package supports
	134	these methods by checking for corresponding C<Features>.
7a2e2cd6	135
cb31d310	136	=head1 EXPORTS
	137
	138	None
	139
a737e074	140	=head1 ENVIRONMENT
	141
	142	The variable C<PERL_RL> governs which ReadLine clone is loaded. If the
	143	value is false, a dummy interface is used. If the value is true, it
	144	should be tail of the name of the package to use, such as C<Perl> or
	145	C<Gnu>.
	146
	147	If the variable is not set, the best available package is loaded.
	148
cb31d310	149	=cut
	150
	151	package Term::ReadLine::Stub;
7a2e2cd6	152	@ISA = qw'Term::ReadLine::Tk Term::ReadLine::TermCap';
cb31d310	153
cb31d310	154	$DB::emacs = $DB::emacs; # To peacify -w
7a2e2cd6	155	*rl_term_set = \@Term::ReadLine::TermCap::rl_term_set;
cb31d310	156
	157	sub ReadLine {'Term::ReadLine::Stub'}
	158	sub readline {
a737e074	159	my $self = shift;
a737e074	160	my ($in,$out,$str) = @$self;
7a2e2cd6	161	print $out $rl_term_set[0], shift, $rl_term_set[1], $rl_term_set[2];
a737e074	162	$self->register_Tk
	163	if not $Term::ReadLine::registered and $Term::ReadLine::toloop
	164	and defined &Tk::DoOneEvent;
	165	#$str = scalar <$in>;
	166	$str = $self->get_line;
7a2e2cd6	167	print $out $rl_term_set[3];
cb31d310	168	# bug in 5.000: chomping empty string creats length -1:
	169	chomp $str if defined $str;
	170	$str;
	171	}
	172	sub addhistory {}
	173
	174	sub findConsole {
	175	my $console;
	176
	177	if (-e "/dev/tty") {
	178	$console = "/dev/tty";
8878e869	179	} elsif (-e "con" or $^O eq 'MSWin32') {
cb31d310	180	$console = "con";
	181	} else {
	182	$console = "sys\$command";
	183	}
	184
287f63d2	185	if ($^O eq 'amigaos') {
	186	$console = undef;
	187	}
	188	elsif ($^O eq 'os2') {
cb31d310	189	if ($DB::emacs) {
	190	$console = undef;
	191	} else {
	192	$console = "/dev/con";
	193	}
	194	}
	195
	196	$consoleOUT = $console;
	197	$console = "&STDIN" unless defined $console;
	198	if (!defined $consoleOUT) {
	199	$consoleOUT = defined fileno(STDERR) ? "&STDERR" : "&STDOUT";
	200	}
	201	($console,$consoleOUT);
	202	}
	203
	204	sub new {
	205	die "method new called with wrong number of arguments"
	206	unless @_==2 or @_==4;
	207	#local (FIN, FOUT);
	208	my ($FIN, $FOUT);
	209	if (@_==2) {
	210	($console, $consoleOUT) = findConsole;
	211
	212	open(FIN, "<$console");
	213	open(FOUT,">$consoleOUT");
	214	#OUT->autoflush(1); # Conflicts with debugger?
	215	$sel = select(FOUT);
	216	$\| = 1; # for DB::OUT
	217	select($sel);
	218	bless [\FIN, \FOUT];
	219	} else { # Filehandles supplied
	220	$FIN = $_[2]; $FOUT = $_[3];
	221	#OUT->autoflush(1); # Conflicts with debugger?
	222	$sel = select($FOUT);
	223	$\| = 1; # for DB::OUT
	224	select($sel);
	225	bless [$FIN, $FOUT];
	226	}
	227	}
f36776d9	228
	229	sub newTTY {
	230	my ($self, $in, $out) = @_;
	231	$self->[0] = $in;
	232	$self->[1] = $out;
	233	my $sel = select($out);
	234	$\| = 1; # for DB::OUT
	235	select($sel);
	236	}
	237
cb31d310	238	sub IN { shift->[0] }
	239	sub OUT { shift->[1] }
	240	sub MinLine { undef }
a737e074	241	sub Attribs { {} }
a737e074	242
84902520	243	my %features = (tkRunning => 1, ornaments => 1, 'newTTY' => 1);
a737e074	244	sub Features { \%features }
cb31d310	245
cb31d310	246	package Term::ReadLine; # So late to allow the above code be defined?
a737e074	247
	248	my $which = $ENV{PERL_RL};
	249	if ($which) {
	250	if ($which =~ /\bgnu\b/i){
	251	eval "use Term::ReadLine::Gnu;";
	252	} elsif ($which =~ /\bperl\b/i) {
	253	eval "use Term::ReadLine::Perl;";
	254	} else {
	255	eval "use Term::ReadLine::$which;";
	256	}
	257	} elsif (defined $which) { # Defined but false
	258	# Do nothing fancy
	259	} else {
	260	eval "use Term::ReadLine::Gnu; 1" or eval "use Term::ReadLine::Perl; 1";
	261	}
cb31d310	262
	263	#require FileHandle;
	264
	265	# To make possible switch off RL in debugger: (Not needed, work done
	266	# in debugger).
	267
	268	if (defined &Term::ReadLine::Gnu::readline) {
	269	@ISA = qw(Term::ReadLine::Gnu Term::ReadLine::Stub);
	270	} elsif (defined &Term::ReadLine::Perl::readline) {
	271	@ISA = qw(Term::ReadLine::Perl Term::ReadLine::Stub);
	272	} else {
	273	@ISA = qw(Term::ReadLine::Stub);
	274	}
	275
7a2e2cd6	276	package Term::ReadLine::TermCap;
	277
	278	# Prompt-start, prompt-end, command-line-start, command-line-end
	279	# -- zero-width beautifies to emit around prompt and the command line.
	280	@rl_term_set = ("","","","");
	281	# string encoded:
	282	$rl_term_set = ',,,';
	283
	284	sub LoadTermCap {
	285	return if defined $terminal;
	286
	287	require Term::Cap;
	288	$terminal = Tgetent Term::Cap ({OSPEED => 9600}); # Avoid warning.
	289	}
	290
	291	sub ornaments {
	292	shift;
	293	return $rl_term_set unless @_;
	294	$rl_term_set = shift;
	295	$rl_term_set \|\|= ',,,';
	296	$rl_term_set = 'us,ue,md,me' if $rl_term_set == 1;
	297	my @ts = split /,/, $rl_term_set, 4;
	298	eval { LoadTermCap };
	299	warn("Cannot find termcap: $@\n"), return unless defined $terminal;
	300	@rl_term_set = map {$_ ? $terminal->Tputs($_,1) \|\| '' : ''} @ts;
	301	return $rl_term_set;
	302	}
	303
	304
a737e074	305	package Term::ReadLine::Tk;
	306
	307	$count_handle = $count_DoOne = $count_loop = 0;
	308
	309	sub handle {$giveup = 1; $count_handle++}
	310
	311	sub Tk_loop {
	312	# Tk->tkwait('variable',\$giveup); # needs Widget
	313	$count_DoOne++, Tk::DoOneEvent(0) until $giveup;
	314	$count_loop++;
	315	$giveup = 0;
	316	}
	317
	318	sub register_Tk {
	319	my $self = shift;
	320	$Term::ReadLine::registered++
	321	or Tk->fileevent($self->IN,'readable',\&handle);
	322	}
	323
	324	sub tkRunning {
	325	$Term::ReadLine::toloop = $_[1] if @_ > 1;
	326	$Term::ReadLine::toloop;
	327	}
	328
	329	sub get_c {
	330	my $self = shift;
	331	$self->Tk_loop if $Term::ReadLine::toloop && defined &Tk::DoOneEvent;
	332	return getc $self->IN;
	333	}
	334
	335	sub get_line {
	336	my $self = shift;
	337	$self->Tk_loop if $Term::ReadLine::toloop && defined &Tk::DoOneEvent;
	338	my $in = $self->IN;
	339	return scalar <$in>;
	340	}
cb31d310	341
	342	1;
	343