3 Term::ReadLine - Perl interface to various C<readline> packages. If
4 no real package is found, substitutes stubs instead of basic functions.
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";
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 $term is a return value of Term::ReadLine-E<gt>Init.
42 returns the actual package that executes the commands. Among possible
43 values are C<Term::ReadLine::Gnu>, C<Term::ReadLine::Perl>,
44 C<Term::ReadLine::Stub Exporter>.
48 returns the handle for subsequent calls to following
49 functions. Argument is the name of the application. Optionally can be
50 followed by two arguments for C<IN> and C<OUT> filehandles. These
51 arguments should be globs.
55 gets an input line, I<possibly> with actual C<readline>
56 support. Trailing newline is removed. Returns C<undef> on C<EOF>.
60 adds the line to the history of input, from where it can be used if
61 the actual C<readline> is present.
65 return the filehandles for input and output or C<undef> if C<readline>
66 input and output cannot be used for Perl.
70 If argument is specified, it is an advice on minimal size of line to
71 be included into history. C<undef> means do not include anything into
72 history. Returns the old value.
76 returns an array with two strings that give most appropriate names for
77 files for input and output using conventions C<"E<lt>$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 two
109 additional methods: C<tkRunning> and C<ornaments>. The first one
110 makes Tk event loop run when waiting for user input (i.e., during
111 C<readline> method), the second one makes the command line stand out
112 by using termcap data. The argument to C<ornaments> should be 0, 1,
113 or a string of a form "aa,bb,cc,dd". Four components of this string
114 should be names of I<terminal capacities>, first two will be issued to
115 make the prompt standout, last two to make the input line standout.
123 The variable C<PERL_RL> governs which ReadLine clone is loaded. If the
124 value is false, a dummy interface is used. If the value is true, it
125 should be tail of the name of the package to use, such as C<Perl> or
128 If the variable is not set, the best available package is loaded.
132 package Term::ReadLine::Stub;
133 @ISA = qw'Term::ReadLine::Tk Term::ReadLine::TermCap';
135 $DB::emacs = $DB::emacs; # To peacify -w
136 *rl_term_set = \@Term::ReadLine::TermCap::rl_term_set;
138 sub ReadLine {'Term::ReadLine::Stub'}
141 my ($in,$out,$str) = @$self;
142 print $out $rl_term_set[0], shift, $rl_term_set[1], $rl_term_set[2];
144 if not $Term::ReadLine::registered and $Term::ReadLine::toloop
145 and defined &Tk::DoOneEvent;
146 #$str = scalar <$in>;
147 $str = $self->get_line;
148 print $out $rl_term_set[3];
149 # bug in 5.000: chomping empty string creats length -1:
150 chomp $str if defined $str;
159 $console = "/dev/tty";
160 } elsif (-e "con" or $^O eq 'MSWin32') {
163 $console = "sys\$command";
166 if ($^O eq 'amigaos') {
169 elsif ($^O eq 'os2') {
173 $console = "/dev/con";
177 $consoleOUT = $console;
178 $console = "&STDIN" unless defined $console;
179 if (!defined $consoleOUT) {
180 $consoleOUT = defined fileno(STDERR) ? "&STDERR" : "&STDOUT";
182 ($console,$consoleOUT);
186 die "method new called with wrong number of arguments"
187 unless @_==2 or @_==4;
188 #local (*FIN, *FOUT);
191 ($console, $consoleOUT) = findConsole;
193 open(FIN, "<$console");
194 open(FOUT,">$consoleOUT");
195 #OUT->autoflush(1); # Conflicts with debugger?
197 $| = 1; # for DB::OUT
199 bless [\*FIN, \*FOUT];
200 } else { # Filehandles supplied
201 $FIN = $_[2]; $FOUT = $_[3];
202 #OUT->autoflush(1); # Conflicts with debugger?
203 $sel = select($FOUT);
204 $| = 1; # for DB::OUT
209 sub IN { shift->[0] }
210 sub OUT { shift->[1] }
211 sub MinLine { undef }
214 my %features = (tkRunning => 1, ornaments => 1);
215 sub Features { \%features }
217 package Term::ReadLine; # So late to allow the above code be defined?
219 my $which = $ENV{PERL_RL};
221 if ($which =~ /\bgnu\b/i){
222 eval "use Term::ReadLine::Gnu;";
223 } elsif ($which =~ /\bperl\b/i) {
224 eval "use Term::ReadLine::Perl;";
226 eval "use Term::ReadLine::$which;";
228 } elsif (defined $which) { # Defined but false
231 eval "use Term::ReadLine::Gnu; 1" or eval "use Term::ReadLine::Perl; 1";
236 # To make possible switch off RL in debugger: (Not needed, work done
239 if (defined &Term::ReadLine::Gnu::readline) {
240 @ISA = qw(Term::ReadLine::Gnu Term::ReadLine::Stub);
241 } elsif (defined &Term::ReadLine::Perl::readline) {
242 @ISA = qw(Term::ReadLine::Perl Term::ReadLine::Stub);
244 @ISA = qw(Term::ReadLine::Stub);
247 package Term::ReadLine::TermCap;
249 # Prompt-start, prompt-end, command-line-start, command-line-end
250 # -- zero-width beautifies to emit around prompt and the command line.
251 @rl_term_set = ("","","","");
253 $rl_term_set = ',,,';
256 return if defined $terminal;
259 $terminal = Tgetent Term::Cap ({OSPEED => 9600}); # Avoid warning.
264 return $rl_term_set unless @_;
265 $rl_term_set = shift;
266 $rl_term_set ||= ',,,';
267 $rl_term_set = 'us,ue,md,me' if $rl_term_set == 1;
268 my @ts = split /,/, $rl_term_set, 4;
269 eval { LoadTermCap };
270 warn("Cannot find termcap: $@\n"), return unless defined $terminal;
271 @rl_term_set = map {$_ ? $terminal->Tputs($_,1) || '' : ''} @ts;
276 package Term::ReadLine::Tk;
278 $count_handle = $count_DoOne = $count_loop = 0;
280 sub handle {$giveup = 1; $count_handle++}
283 # Tk->tkwait('variable',\$giveup); # needs Widget
284 $count_DoOne++, Tk::DoOneEvent(0) until $giveup;
291 $Term::ReadLine::registered++
292 or Tk->fileevent($self->IN,'readable',\&handle);
296 $Term::ReadLine::toloop = $_[1] if @_ > 1;
297 $Term::ReadLine::toloop;
302 $self->Tk_loop if $Term::ReadLine::toloop && defined &Tk::DoOneEvent;
303 return getc $self->IN;
308 $self->Tk_loop if $Term::ReadLine::toloop && defined &Tk::DoOneEvent;