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1 | =head1 NAME |
2 | |
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3 | Term::ReadLine - Perl interface to various C<readline> packages. If |
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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 | |
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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 | |
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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 | |
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36 | where $term is a return value of Term::ReadLine-E<gt>Init. |
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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>, $C<OUT> |
64 | |
65 | return the filehandles for input and output or C<undef> if C<readline> |
66 | input and output cannot be used for Perl. |
67 | |
68 | =item C<MinLine> |
69 | |
70 | If argument is specified, it is an advice on minimal size of line to |
71 | be included into history. C<undef> means do not include anything into |
72 | history. Returns the old value. |
73 | |
74 | =item C<findConsole> |
75 | |
76 | returns an array with two strings that give most appropriate names for |
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77 | files for input and output using conventions C<"E<lt>$in">, C<"E<gt>out">. |
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78 | |
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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 | |
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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 | |
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95 | If C<Features> method reports a feature C<attribs> as present, the |
96 | method C<Attribs> is not dummy. |
97 | |
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98 | =back |
99 | |
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100 | =head1 Additional supported functions |
101 | |
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102 | Actually C<Term::ReadLine> can use some other package, that will |
103 | support reacher set of commands. |
104 | |
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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 | |
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108 | The stub package included with the perl distribution allows some |
109 | additional methods: |
110 | |
111 | =over 12 |
112 | |
113 | =item C<tkRunning> |
114 | |
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115 | makes Tk event loop run when waiting for user input (i.e., during |
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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>. |
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135 | |
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136 | =head1 EXPORTS |
137 | |
138 | None |
139 | |
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140 | =head1 ENVIRONMENT |
141 | |
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142 | The environment variable C<PERL_RL> governs which ReadLine clone is |
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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 |
145 | C<Perl> or C<Gnu>. |
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146 | |
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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 |
150 | |
151 | If the variable is not set, or if the head of space-separated list is |
152 | empty, the best available package is loaded. |
153 | |
154 | export "PERL_RL=Perl o=0" # Use Perl ReadLine without ornaments |
155 | export "PERL_RL= o=0" # Use best available ReadLine without ornaments |
156 | |
157 | (Note that processing of C<PERL_RL> for ornaments is in the discretion of the |
158 | particular used C<Term::ReadLine::*> package). |
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159 | |
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160 | =cut |
161 | |
162 | package Term::ReadLine::Stub; |
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163 | @ISA = qw'Term::ReadLine::Tk Term::ReadLine::TermCap'; |
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164 | |
165 | $DB::emacs = $DB::emacs; # To peacify -w |
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166 | *rl_term_set = \@Term::ReadLine::TermCap::rl_term_set; |
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167 | |
168 | sub ReadLine {'Term::ReadLine::Stub'} |
169 | sub readline { |
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170 | my $self = shift; |
171 | my ($in,$out,$str) = @$self; |
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172 | print $out $rl_term_set[0], shift, $rl_term_set[1], $rl_term_set[2]; |
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173 | $self->register_Tk |
174 | if not $Term::ReadLine::registered and $Term::ReadLine::toloop |
175 | and defined &Tk::DoOneEvent; |
176 | #$str = scalar <$in>; |
177 | $str = $self->get_line; |
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178 | print $out $rl_term_set[3]; |
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179 | # bug in 5.000: chomping empty string creats length -1: |
180 | chomp $str if defined $str; |
181 | $str; |
182 | } |
183 | sub addhistory {} |
184 | |
185 | sub findConsole { |
186 | my $console; |
187 | |
188 | if (-e "/dev/tty") { |
189 | $console = "/dev/tty"; |
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190 | } elsif (-e "con" or $^O eq 'MSWin32') { |
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191 | $console = "con"; |
192 | } else { |
193 | $console = "sys\$command"; |
194 | } |
195 | |
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196 | if (($^O eq 'amigaos') || ($^O eq 'beos')) { |
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197 | $console = undef; |
198 | } |
199 | elsif ($^O eq 'os2') { |
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200 | if ($DB::emacs) { |
201 | $console = undef; |
202 | } else { |
203 | $console = "/dev/con"; |
204 | } |
205 | } |
206 | |
207 | $consoleOUT = $console; |
208 | $console = "&STDIN" unless defined $console; |
209 | if (!defined $consoleOUT) { |
210 | $consoleOUT = defined fileno(STDERR) ? "&STDERR" : "&STDOUT"; |
211 | } |
212 | ($console,$consoleOUT); |
213 | } |
214 | |
215 | sub new { |
216 | die "method new called with wrong number of arguments" |
217 | unless @_==2 or @_==4; |
218 | #local (*FIN, *FOUT); |
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219 | my ($FIN, $FOUT, $ret); |
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220 | if (@_==2) { |
221 | ($console, $consoleOUT) = findConsole; |
222 | |
223 | open(FIN, "<$console"); |
224 | open(FOUT,">$consoleOUT"); |
225 | #OUT->autoflush(1); # Conflicts with debugger? |
226 | $sel = select(FOUT); |
227 | $| = 1; # for DB::OUT |
228 | select($sel); |
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229 | $ret = bless [\*FIN, \*FOUT]; |
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230 | } else { # Filehandles supplied |
231 | $FIN = $_[2]; $FOUT = $_[3]; |
232 | #OUT->autoflush(1); # Conflicts with debugger? |
233 | $sel = select($FOUT); |
234 | $| = 1; # for DB::OUT |
235 | select($sel); |
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236 | $ret = bless [$FIN, $FOUT]; |
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237 | } |
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238 | if ($ret->Features->{ornaments} |
239 | and not ($ENV{PERL_RL} and $ENV{PERL_RL} =~ /\bo\w*=0/)) { |
240 | local $Term::ReadLine::termcap_nowarn = 1; |
241 | $ret->ornaments(1); |
242 | } |
243 | return $ret; |
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244 | } |
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245 | |
246 | sub newTTY { |
247 | my ($self, $in, $out) = @_; |
248 | $self->[0] = $in; |
249 | $self->[1] = $out; |
250 | my $sel = select($out); |
251 | $| = 1; # for DB::OUT |
252 | select($sel); |
253 | } |
254 | |
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255 | sub IN { shift->[0] } |
256 | sub OUT { shift->[1] } |
257 | sub MinLine { undef } |
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258 | sub Attribs { {} } |
259 | |
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260 | my %features = (tkRunning => 1, ornaments => 1, 'newTTY' => 1); |
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261 | sub Features { \%features } |
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262 | |
263 | package Term::ReadLine; # So late to allow the above code be defined? |
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264 | |
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265 | my ($which) = exists $ENV{PERL_RL} ? split /\s+/, $ENV{PERL_RL} : undef; |
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266 | if ($which) { |
267 | if ($which =~ /\bgnu\b/i){ |
268 | eval "use Term::ReadLine::Gnu;"; |
269 | } elsif ($which =~ /\bperl\b/i) { |
270 | eval "use Term::ReadLine::Perl;"; |
271 | } else { |
272 | eval "use Term::ReadLine::$which;"; |
273 | } |
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274 | } elsif (defined $which and $which ne '') { # Defined but false |
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275 | # Do nothing fancy |
276 | } else { |
277 | eval "use Term::ReadLine::Gnu; 1" or eval "use Term::ReadLine::Perl; 1"; |
278 | } |
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279 | |
280 | #require FileHandle; |
281 | |
282 | # To make possible switch off RL in debugger: (Not needed, work done |
283 | # in debugger). |
284 | |
285 | if (defined &Term::ReadLine::Gnu::readline) { |
286 | @ISA = qw(Term::ReadLine::Gnu Term::ReadLine::Stub); |
287 | } elsif (defined &Term::ReadLine::Perl::readline) { |
288 | @ISA = qw(Term::ReadLine::Perl Term::ReadLine::Stub); |
289 | } else { |
290 | @ISA = qw(Term::ReadLine::Stub); |
291 | } |
292 | |
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293 | package Term::ReadLine::TermCap; |
294 | |
295 | # Prompt-start, prompt-end, command-line-start, command-line-end |
296 | # -- zero-width beautifies to emit around prompt and the command line. |
297 | @rl_term_set = ("","","",""); |
298 | # string encoded: |
299 | $rl_term_set = ',,,'; |
300 | |
301 | sub LoadTermCap { |
302 | return if defined $terminal; |
303 | |
304 | require Term::Cap; |
305 | $terminal = Tgetent Term::Cap ({OSPEED => 9600}); # Avoid warning. |
306 | } |
307 | |
308 | sub ornaments { |
309 | shift; |
310 | return $rl_term_set unless @_; |
311 | $rl_term_set = shift; |
312 | $rl_term_set ||= ',,,'; |
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313 | $rl_term_set = 'us,ue,md,me' if $rl_term_set eq '1'; |
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314 | my @ts = split /,/, $rl_term_set, 4; |
315 | eval { LoadTermCap }; |
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316 | unless (defined $terminal) { |
317 | warn("Cannot find termcap: $@\n") unless $Term::ReadLine::termcap_nowarn; |
318 | $rl_term_set = ',,,'; |
319 | return; |
320 | } |
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321 | @rl_term_set = map {$_ ? $terminal->Tputs($_,1) || '' : ''} @ts; |
322 | return $rl_term_set; |
323 | } |
324 | |
325 | |
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326 | package Term::ReadLine::Tk; |
327 | |
328 | $count_handle = $count_DoOne = $count_loop = 0; |
329 | |
330 | sub handle {$giveup = 1; $count_handle++} |
331 | |
332 | sub Tk_loop { |
333 | # Tk->tkwait('variable',\$giveup); # needs Widget |
334 | $count_DoOne++, Tk::DoOneEvent(0) until $giveup; |
335 | $count_loop++; |
336 | $giveup = 0; |
337 | } |
338 | |
339 | sub register_Tk { |
340 | my $self = shift; |
341 | $Term::ReadLine::registered++ |
342 | or Tk->fileevent($self->IN,'readable',\&handle); |
343 | } |
344 | |
345 | sub tkRunning { |
346 | $Term::ReadLine::toloop = $_[1] if @_ > 1; |
347 | $Term::ReadLine::toloop; |
348 | } |
349 | |
350 | sub get_c { |
351 | my $self = shift; |
352 | $self->Tk_loop if $Term::ReadLine::toloop && defined &Tk::DoOneEvent; |
353 | return getc $self->IN; |
354 | } |
355 | |
356 | sub get_line { |
357 | my $self = shift; |
358 | $self->Tk_loop if $Term::ReadLine::toloop && defined &Tk::DoOneEvent; |
359 | my $in = $self->IN; |
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360 | local ($/) = "\n"; |
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361 | return scalar <$in>; |
362 | } |
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363 | |
364 | 1; |
365 | |