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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 | =head1 EXPORTS |
109 | |
110 | None |
111 | |
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112 | =head1 ENVIRONMENT |
113 | |
114 | The variable C<PERL_RL> governs which ReadLine clone is loaded. If the |
115 | value is false, a dummy interface is used. If the value is true, it |
116 | should be tail of the name of the package to use, such as C<Perl> or |
117 | C<Gnu>. |
118 | |
119 | If the variable is not set, the best available package is loaded. |
120 | |
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121 | =cut |
122 | |
123 | package Term::ReadLine::Stub; |
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124 | @ISA = 'Term::ReadLine::Tk'; |
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125 | |
126 | $DB::emacs = $DB::emacs; # To peacify -w |
127 | |
128 | sub ReadLine {'Term::ReadLine::Stub'} |
129 | sub readline { |
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130 | my $self = shift; |
131 | my ($in,$out,$str) = @$self; |
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132 | print $out shift; |
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133 | $self->register_Tk |
134 | if not $Term::ReadLine::registered and $Term::ReadLine::toloop |
135 | and defined &Tk::DoOneEvent; |
136 | #$str = scalar <$in>; |
137 | $str = $self->get_line; |
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138 | # bug in 5.000: chomping empty string creats length -1: |
139 | chomp $str if defined $str; |
140 | $str; |
141 | } |
142 | sub addhistory {} |
143 | |
144 | sub findConsole { |
145 | my $console; |
146 | |
147 | if (-e "/dev/tty") { |
148 | $console = "/dev/tty"; |
149 | } elsif (-e "con") { |
150 | $console = "con"; |
151 | } else { |
152 | $console = "sys\$command"; |
153 | } |
154 | |
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155 | if ($^O eq 'amigaos') { |
156 | $console = undef; |
157 | } |
158 | elsif ($^O eq 'os2') { |
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159 | if ($DB::emacs) { |
160 | $console = undef; |
161 | } else { |
162 | $console = "/dev/con"; |
163 | } |
164 | } |
165 | |
166 | $consoleOUT = $console; |
167 | $console = "&STDIN" unless defined $console; |
168 | if (!defined $consoleOUT) { |
169 | $consoleOUT = defined fileno(STDERR) ? "&STDERR" : "&STDOUT"; |
170 | } |
171 | ($console,$consoleOUT); |
172 | } |
173 | |
174 | sub new { |
175 | die "method new called with wrong number of arguments" |
176 | unless @_==2 or @_==4; |
177 | #local (*FIN, *FOUT); |
178 | my ($FIN, $FOUT); |
179 | if (@_==2) { |
180 | ($console, $consoleOUT) = findConsole; |
181 | |
182 | open(FIN, "<$console"); |
183 | open(FOUT,">$consoleOUT"); |
184 | #OUT->autoflush(1); # Conflicts with debugger? |
185 | $sel = select(FOUT); |
186 | $| = 1; # for DB::OUT |
187 | select($sel); |
188 | bless [\*FIN, \*FOUT]; |
189 | } else { # Filehandles supplied |
190 | $FIN = $_[2]; $FOUT = $_[3]; |
191 | #OUT->autoflush(1); # Conflicts with debugger? |
192 | $sel = select($FOUT); |
193 | $| = 1; # for DB::OUT |
194 | select($sel); |
195 | bless [$FIN, $FOUT]; |
196 | } |
197 | } |
198 | sub IN { shift->[0] } |
199 | sub OUT { shift->[1] } |
200 | sub MinLine { undef } |
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201 | sub Attribs { {} } |
202 | |
203 | my %features = (tkRunning => 1); |
204 | sub Features { \%features } |
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205 | |
206 | package Term::ReadLine; # So late to allow the above code be defined? |
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207 | |
208 | my $which = $ENV{PERL_RL}; |
209 | if ($which) { |
210 | if ($which =~ /\bgnu\b/i){ |
211 | eval "use Term::ReadLine::Gnu;"; |
212 | } elsif ($which =~ /\bperl\b/i) { |
213 | eval "use Term::ReadLine::Perl;"; |
214 | } else { |
215 | eval "use Term::ReadLine::$which;"; |
216 | } |
217 | } elsif (defined $which) { # Defined but false |
218 | # Do nothing fancy |
219 | } else { |
220 | eval "use Term::ReadLine::Gnu; 1" or eval "use Term::ReadLine::Perl; 1"; |
221 | } |
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222 | |
223 | #require FileHandle; |
224 | |
225 | # To make possible switch off RL in debugger: (Not needed, work done |
226 | # in debugger). |
227 | |
228 | if (defined &Term::ReadLine::Gnu::readline) { |
229 | @ISA = qw(Term::ReadLine::Gnu Term::ReadLine::Stub); |
230 | } elsif (defined &Term::ReadLine::Perl::readline) { |
231 | @ISA = qw(Term::ReadLine::Perl Term::ReadLine::Stub); |
232 | } else { |
233 | @ISA = qw(Term::ReadLine::Stub); |
234 | } |
235 | |
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236 | package Term::ReadLine::Tk; |
237 | |
238 | $count_handle = $count_DoOne = $count_loop = 0; |
239 | |
240 | sub handle {$giveup = 1; $count_handle++} |
241 | |
242 | sub Tk_loop { |
243 | # Tk->tkwait('variable',\$giveup); # needs Widget |
244 | $count_DoOne++, Tk::DoOneEvent(0) until $giveup; |
245 | $count_loop++; |
246 | $giveup = 0; |
247 | } |
248 | |
249 | sub register_Tk { |
250 | my $self = shift; |
251 | $Term::ReadLine::registered++ |
252 | or Tk->fileevent($self->IN,'readable',\&handle); |
253 | } |
254 | |
255 | sub tkRunning { |
256 | $Term::ReadLine::toloop = $_[1] if @_ > 1; |
257 | $Term::ReadLine::toloop; |
258 | } |
259 | |
260 | sub get_c { |
261 | my $self = shift; |
262 | $self->Tk_loop if $Term::ReadLine::toloop && defined &Tk::DoOneEvent; |
263 | return getc $self->IN; |
264 | } |
265 | |
266 | sub get_line { |
267 | my $self = shift; |
268 | $self->Tk_loop if $Term::ReadLine::toloop && defined &Tk::DoOneEvent; |
269 | my $in = $self->IN; |
270 | return scalar <$in>; |
271 | } |
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272 | |
273 | 1; |
274 | |