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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 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. |
116 | |
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117 | =head1 EXPORTS |
118 | |
119 | None |
120 | |
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121 | =head1 ENVIRONMENT |
122 | |
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 |
126 | C<Gnu>. |
127 | |
128 | If the variable is not set, the best available package is loaded. |
129 | |
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130 | =cut |
131 | |
132 | package Term::ReadLine::Stub; |
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133 | @ISA = qw'Term::ReadLine::Tk Term::ReadLine::TermCap'; |
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134 | |
135 | $DB::emacs = $DB::emacs; # To peacify -w |
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136 | *rl_term_set = \@Term::ReadLine::TermCap::rl_term_set; |
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137 | |
138 | sub ReadLine {'Term::ReadLine::Stub'} |
139 | sub readline { |
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140 | my $self = shift; |
141 | my ($in,$out,$str) = @$self; |
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142 | print $out $rl_term_set[0], shift, $rl_term_set[1], $rl_term_set[2]; |
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143 | $self->register_Tk |
144 | if not $Term::ReadLine::registered and $Term::ReadLine::toloop |
145 | and defined &Tk::DoOneEvent; |
146 | #$str = scalar <$in>; |
147 | $str = $self->get_line; |
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148 | print $out $rl_term_set[3]; |
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149 | # bug in 5.000: chomping empty string creats length -1: |
150 | chomp $str if defined $str; |
151 | $str; |
152 | } |
153 | sub addhistory {} |
154 | |
155 | sub findConsole { |
156 | my $console; |
157 | |
158 | if (-e "/dev/tty") { |
159 | $console = "/dev/tty"; |
160 | } elsif (-e "con") { |
161 | $console = "con"; |
162 | } else { |
163 | $console = "sys\$command"; |
164 | } |
165 | |
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166 | if ($^O eq 'amigaos') { |
167 | $console = undef; |
168 | } |
169 | elsif ($^O eq 'os2') { |
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170 | if ($DB::emacs) { |
171 | $console = undef; |
172 | } else { |
173 | $console = "/dev/con"; |
174 | } |
175 | } |
176 | |
177 | $consoleOUT = $console; |
178 | $console = "&STDIN" unless defined $console; |
179 | if (!defined $consoleOUT) { |
180 | $consoleOUT = defined fileno(STDERR) ? "&STDERR" : "&STDOUT"; |
181 | } |
182 | ($console,$consoleOUT); |
183 | } |
184 | |
185 | sub new { |
186 | die "method new called with wrong number of arguments" |
187 | unless @_==2 or @_==4; |
188 | #local (*FIN, *FOUT); |
189 | my ($FIN, $FOUT); |
190 | if (@_==2) { |
191 | ($console, $consoleOUT) = findConsole; |
192 | |
193 | open(FIN, "<$console"); |
194 | open(FOUT,">$consoleOUT"); |
195 | #OUT->autoflush(1); # Conflicts with debugger? |
196 | $sel = select(FOUT); |
197 | $| = 1; # for DB::OUT |
198 | select($sel); |
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 | $| = 1; # for DB::OUT |
205 | select($sel); |
206 | bless [$FIN, $FOUT]; |
207 | } |
208 | } |
209 | sub IN { shift->[0] } |
210 | sub OUT { shift->[1] } |
211 | sub MinLine { undef } |
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212 | sub Attribs { {} } |
213 | |
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214 | my %features = (tkRunning => 1, ornaments => 1); |
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215 | sub Features { \%features } |
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216 | |
217 | package Term::ReadLine; # So late to allow the above code be defined? |
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218 | |
219 | my $which = $ENV{PERL_RL}; |
220 | if ($which) { |
221 | if ($which =~ /\bgnu\b/i){ |
222 | eval "use Term::ReadLine::Gnu;"; |
223 | } elsif ($which =~ /\bperl\b/i) { |
224 | eval "use Term::ReadLine::Perl;"; |
225 | } else { |
226 | eval "use Term::ReadLine::$which;"; |
227 | } |
228 | } elsif (defined $which) { # Defined but false |
229 | # Do nothing fancy |
230 | } else { |
231 | eval "use Term::ReadLine::Gnu; 1" or eval "use Term::ReadLine::Perl; 1"; |
232 | } |
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233 | |
234 | #require FileHandle; |
235 | |
236 | # To make possible switch off RL in debugger: (Not needed, work done |
237 | # in debugger). |
238 | |
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); |
243 | } else { |
244 | @ISA = qw(Term::ReadLine::Stub); |
245 | } |
246 | |
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247 | package Term::ReadLine::TermCap; |
248 | |
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 = ("","","",""); |
252 | # string encoded: |
253 | $rl_term_set = ',,,'; |
254 | |
255 | sub LoadTermCap { |
256 | return if defined $terminal; |
257 | |
258 | require Term::Cap; |
259 | $terminal = Tgetent Term::Cap ({OSPEED => 9600}); # Avoid warning. |
260 | } |
261 | |
262 | sub ornaments { |
263 | shift; |
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; |
272 | return $rl_term_set; |
273 | } |
274 | |
275 | |
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276 | package Term::ReadLine::Tk; |
277 | |
278 | $count_handle = $count_DoOne = $count_loop = 0; |
279 | |
280 | sub handle {$giveup = 1; $count_handle++} |
281 | |
282 | sub Tk_loop { |
283 | # Tk->tkwait('variable',\$giveup); # needs Widget |
284 | $count_DoOne++, Tk::DoOneEvent(0) until $giveup; |
285 | $count_loop++; |
286 | $giveup = 0; |
287 | } |
288 | |
289 | sub register_Tk { |
290 | my $self = shift; |
291 | $Term::ReadLine::registered++ |
292 | or Tk->fileevent($self->IN,'readable',\&handle); |
293 | } |
294 | |
295 | sub tkRunning { |
296 | $Term::ReadLine::toloop = $_[1] if @_ > 1; |
297 | $Term::ReadLine::toloop; |
298 | } |
299 | |
300 | sub get_c { |
301 | my $self = shift; |
302 | $self->Tk_loop if $Term::ReadLine::toloop && defined &Tk::DoOneEvent; |
303 | return getc $self->IN; |
304 | } |
305 | |
306 | sub get_line { |
307 | my $self = shift; |
308 | $self->Tk_loop if $Term::ReadLine::toloop && defined &Tk::DoOneEvent; |
309 | my $in = $self->IN; |
310 | return scalar <$in>; |
311 | } |
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312 | |
313 | 1; |
314 | |