3 Term::ReadLine - Perl interface to various C<readline> packages.
4 If no real package is found, substitutes stubs instead of basic functions.
9 my $term = new Term::ReadLine 'Simple Perl calc';
10 my $prompt = "Enter your arithmetic expression: ";
11 my $OUT = $term->OUT || \*STDOUT;
12 while ( defined ($_ = $term->readline($prompt)) ) {
15 print $OUT $res, "\n" unless $@;
16 $term->addhistory($_) if /\S/;
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.
26 =head1 Minimal set of supported functions
28 All the supported functions should be called as methods, i.e., either as
30 $term = new Term::ReadLine 'name';
34 $term->addhistory('row');
36 where $term is a return value of Term::ReadLine-E<gt>new().
42 returns the actual package that executes the commands. Among possible
43 values are C<Term::ReadLine::Gnu>, C<Term::ReadLine::Perl>,
44 C<Term::ReadLine::Stub>.
48 returns the handle for subsequent calls to following
49 functions. Argument is the name of the application. Optionally can be
50 followed by two arguments for C<IN> and C<OUT> filehandles. These
51 arguments should be globs.
55 gets an input line, I<possibly> with actual C<readline>
56 support. Trailing newline is removed. Returns C<undef> on C<EOF>.
60 adds the line to the history of input, from where it can be used if
61 the actual C<readline> is present.
65 return the filehandles for input and output or C<undef> if C<readline>
66 input and output cannot be used for Perl.
70 If argument is specified, it is an advice on minimal size of line to
71 be included into history. C<undef> means do not include anything into
72 history. Returns the old value.
76 returns an array with two strings that give most appropriate names for
77 files for input and output using conventions C<"E<lt>$in">, C<"E<gt>out">.
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.
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.
95 If C<Features> method reports a feature C<attribs> as present, the
96 method C<Attribs> is not dummy.
100 =head1 Additional supported functions
102 Actually C<Term::ReadLine> can use some other package, that will
103 support reacher set of commands.
105 All these commands are callable via method interface and have names
106 which conform to standard conventions with the leading C<rl_> stripped.
108 The stub package included with the perl distribution allows some
115 makes Tk event loop run when waiting for user input (i.e., during
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.
128 takes two arguments which are input filehandle and output filehandle.
129 Switches to use these filehandles.
133 One can check whether the currently loaded ReadLine package supports
134 these methods by checking for corresponding C<Features>.
142 The environment variable C<PERL_RL> governs which ReadLine clone is
143 loaded. If the value is false, a dummy interface is used. If the value
144 is true, it should be tail of the name of the package to use, such as
147 As a special case, if the value of this variable is space-separated,
148 the tail might be used to disable the ornaments by setting the tail to
149 be C<o=0> or C<ornaments=0>. The head should be as described above, say
151 If the variable is not set, or if the head of space-separated list is
152 empty, the best available package is loaded.
154 export "PERL_RL=Perl o=0" # Use Perl ReadLine without ornaments
155 export "PERL_RL= o=0" # Use best available ReadLine without ornaments
157 (Note that processing of C<PERL_RL> for ornaments is in the discretion of the
158 particular used C<Term::ReadLine::*> package).
162 It seems that using Term::ReadLine from Emacs minibuffer doesn't work
163 quite right and one will get an error message like
165 Cannot open /dev/tty for read at ...
167 One possible workaround for this is to explicitly open /dev/tty like this
169 open (FH, "/dev/tty" )
170 or eval 'sub Term::ReadLine::findConsole { ("&STDIN", "&STDERR") }';
174 or you can try using the 4-argument form of Term::ReadLine->new().
180 package Term::ReadLine::Stub;
181 our @ISA = qw'Term::ReadLine::Tk Term::ReadLine::TermCap';
183 $DB::emacs = $DB::emacs; # To peacify -w
185 *rl_term_set = \@Term::ReadLine::TermCap::rl_term_set;
187 sub PERL_UNICODE_STDIN () { 0x0001 }
189 sub ReadLine {'Term::ReadLine::Stub'}
192 my ($in,$out,$str) = @$self;
194 print $out $rl_term_set[0], $prompt, $rl_term_set[1], $rl_term_set[2];
196 if not $Term::ReadLine::registered and $Term::ReadLine::toloop
197 and defined &Tk::DoOneEvent;
198 #$str = scalar <$in>;
199 $str = $self->get_line;
200 $str =~ s/^\s*\Q$prompt\E// if ($^O eq 'MacOS');
202 if ${^UNICODE} & PERL_UNICODE_STDIN || defined ${^ENCODING};
203 print $out $rl_term_set[3];
204 # bug in 5.000: chomping empty string creats length -1:
205 chomp $str if defined $str;
213 if ($^O eq 'MacOS') {
214 $console = "Dev:Console";
215 } elsif (-e "/dev/tty") {
216 $console = "/dev/tty";
217 } elsif (-e "con" or $^O eq 'MSWin32') {
220 $console = "sys\$command";
223 if (($^O eq 'amigaos') || ($^O eq 'beos') || ($^O eq 'epoc')) {
226 elsif ($^O eq 'os2') {
230 $console = "/dev/con";
234 my $consoleOUT = $console;
235 $console = "&STDIN" unless defined $console;
236 if (!defined $consoleOUT) {
237 $consoleOUT = defined fileno(STDERR) ? "&STDERR" : "&STDOUT";
239 ($console,$consoleOUT);
243 die "method new called with wrong number of arguments"
244 unless @_==2 or @_==4;
245 #local (*FIN, *FOUT);
246 my ($FIN, $FOUT, $ret);
248 my($console, $consoleOUT) = $_[0]->findConsole;
250 open(FIN, "<$console");
251 open(FOUT,">$consoleOUT");
252 #OUT->autoflush(1); # Conflicts with debugger?
253 my $sel = select(FOUT);
254 $| = 1; # for DB::OUT
256 $ret = bless [\*FIN, \*FOUT];
257 } else { # Filehandles supplied
258 $FIN = $_[2]; $FOUT = $_[3];
259 #OUT->autoflush(1); # Conflicts with debugger?
260 my $sel = select($FOUT);
261 $| = 1; # for DB::OUT
263 $ret = bless [$FIN, $FOUT];
265 if ($ret->Features->{ornaments}
266 and not ($ENV{PERL_RL} and $ENV{PERL_RL} =~ /\bo\w*=0/)) {
267 local $Term::ReadLine::termcap_nowarn = 1;
274 my ($self, $in, $out) = @_;
277 my $sel = select($out);
278 $| = 1; # for DB::OUT
282 sub IN { shift->[0] }
283 sub OUT { shift->[1] }
284 sub MinLine { undef }
287 my %features = (tkRunning => 1, ornaments => 1, 'newTTY' => 1);
288 sub Features { \%features }
290 package Term::ReadLine; # So late to allow the above code be defined?
292 our $VERSION = '1.00';
294 my ($which) = exists $ENV{PERL_RL} ? split /\s+/, $ENV{PERL_RL} : undef;
296 if ($which =~ /\bgnu\b/i){
297 eval "use Term::ReadLine::Gnu;";
298 } elsif ($which =~ /\bperl\b/i) {
299 eval "use Term::ReadLine::Perl;";
301 eval "use Term::ReadLine::$which;";
303 } elsif (defined $which and $which ne '') { # Defined but false
306 eval "use Term::ReadLine::Gnu; 1" or eval "use Term::ReadLine::Perl; 1";
311 # To make possible switch off RL in debugger: (Not needed, work done
314 if (defined &Term::ReadLine::Gnu::readline) {
315 @ISA = qw(Term::ReadLine::Gnu Term::ReadLine::Stub);
316 } elsif (defined &Term::ReadLine::Perl::readline) {
317 @ISA = qw(Term::ReadLine::Perl Term::ReadLine::Stub);
318 } elsif (defined $which && defined &{"Term::ReadLine::$which\::readline"}) {
319 @ISA = "Term::ReadLine::$which";
321 @ISA = qw(Term::ReadLine::Stub);
324 package Term::ReadLine::TermCap;
326 # Prompt-start, prompt-end, command-line-start, command-line-end
327 # -- zero-width beautifies to emit around prompt and the command line.
328 our @rl_term_set = ("","","","");
330 our $rl_term_set = ',,,';
334 return if defined $terminal;
337 $terminal = Tgetent Term::Cap ({OSPEED => 9600}); # Avoid warning.
342 return $rl_term_set unless @_;
343 $rl_term_set = shift;
344 $rl_term_set ||= ',,,';
345 $rl_term_set = 'us,ue,md,me' if $rl_term_set eq '1';
346 my @ts = split /,/, $rl_term_set, 4;
347 eval { LoadTermCap };
348 unless (defined $terminal) {
349 warn("Cannot find termcap: $@\n") unless $Term::ReadLine::termcap_nowarn;
350 $rl_term_set = ',,,';
353 @rl_term_set = map {$_ ? $terminal->Tputs($_,1) || '' : ''} @ts;
358 package Term::ReadLine::Tk;
360 our($count_handle, $count_DoOne, $count_loop);
361 $count_handle = $count_DoOne = $count_loop = 0;
364 sub handle {$giveup = 1; $count_handle++}
367 # Tk->tkwait('variable',\$giveup); # needs Widget
368 $count_DoOne++, Tk::DoOneEvent(0) until $giveup;
375 $Term::ReadLine::registered++
376 or Tk->fileevent($self->IN,'readable',\&handle);
380 $Term::ReadLine::toloop = $_[1] if @_ > 1;
381 $Term::ReadLine::toloop;
386 $self->Tk_loop if $Term::ReadLine::toloop && defined &Tk::DoOneEvent;
387 return getc $self->IN;
392 $self->Tk_loop if $Term::ReadLine::toloop && defined &Tk::DoOneEvent;