Move to Moo for fast bootstrapping.
[p5sagit/Devel-REPL.git] / lib / Devel / REPL.pm
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afe61f9c 1package Devel::REPL;
2
3use Term::ReadLine;
e2d0b019 4use Moo;
5use namespace::sweep;
089a0c4e 6use 5.008001; # backwards compat, doesn't warn like 5.8.1
59aedffc 7
bb1f569c 8our $VERSION = '1.003014';
afe61f9c 9
e22aa835 10use Devel::REPL::Error;
e2d0b019 11use Scalar::Util qw/blessed/;
12use Module::Runtime ();
13
14sub load_plugin {
15 my ($self, $plugin) = @_;
16 $plugin = "Devel::REPL::Plugin::$plugin";
17 Module::Runtime::use_module("$plugin");
18 if (my $pre = $plugin->can('BEFORE_PLUGIN')) {
19 $pre->($self, $plugin);
20 }
21 Moo::Role->apply_roles_to_package(
22 'Devel::REPL', $plugin
23 );
24 if (my $pre = $plugin->can('AFTER_PLUGIN')) {
25 $pre->($self, $plugin);
26 }
27}
e22aa835 28
afe61f9c 29has 'term' => (
30 is => 'rw', required => 1,
31 default => sub { Term::ReadLine->new('Perl REPL') }
32);
33
34has 'prompt' => (
35 is => 'rw', required => 1,
36 default => sub { '$ ' }
37);
38
39has 'out_fh' => (
40 is => 'rw', required => 1, lazy => 1,
41 default => sub { shift->term->OUT || \*STDOUT; }
42);
43
57719095 44has 'exit_repl' => (
45 is => 'rw', required => 1,
46 default => sub { 0 }
47);
48
afe61f9c 49sub run {
50 my ($self) = @_;
e22aa835 51 while ($self->run_once_safely) {
57719095 52 # keep looping unless we want to exit REPL
53 last if $self->exit_repl;
afe61f9c 54 }
55}
56
e22aa835 57sub run_once_safely {
58 my ($self, @args) = @_;
59
60 my $ret = eval { $self->run_once(@args) };
61
62 if ($@) {
63 my $error = $@;
64 eval { $self->print("Error! - $error\n"); };
65 return 1;
66 } else {
67 return $ret;
68 }
69}
70
afe61f9c 71sub run_once {
72 my ($self) = @_;
e22aa835 73
afe61f9c 74 my $line = $self->read;
57719095 75 return unless defined($line); # undefined value == EOF
e22aa835 76
77 my @ret = $self->formatted_eval($line);
78
57719095 79 $self->print(@ret) unless $self->exit_repl;
e22aa835 80
afe61f9c 81 return 1;
82}
83
e22aa835 84sub formatted_eval {
85 my ( $self, @args ) = @_;
86
87 my @ret = $self->eval(@args);
88
89 return $self->format(@ret);
90}
91
92sub format {
93 my ( $self, @stuff ) = @_;
94
c3bbf326 95 if ( $self->is_error($stuff[0]) ) {
e22aa835 96 return $self->format_error(@stuff);
97 } else {
98 return $self->format_result(@stuff);
99 }
100}
101
102sub format_result {
103 my ( $self, @stuff ) = @_;
104
105 return @stuff;
106}
107
108sub format_error {
109 my ( $self, $error ) = @_;
110 return $error->stringify;
111}
112
c3bbf326 113sub is_error {
114 my ( $self, $thingy ) = @_;
115 blessed($thingy) and $thingy->isa("Devel::REPL::Error");
116}
117
afe61f9c 118sub read {
119 my ($self) = @_;
120 return $self->term->readline($self->prompt);
121}
122
911a1c24 123sub eval {
124 my ($self, $line) = @_;
c3bbf326 125 my $compiled = $self->compile($line);
126 return $compiled unless defined($compiled) and not $self->is_error($compiled);
127 return $self->execute($compiled);
911a1c24 128}
129
130sub compile {
e22aa835 131 my ( $_REPL, @args ) = @_;
132 my $compiled = eval $_REPL->wrap_as_sub(@args);
c3bbf326 133 return $_REPL->error_return("Compile error", $@) if $@;
911a1c24 134 return $compiled;
135}
136
137sub wrap_as_sub {
e22aa835 138 my ($self, $line, %args) = @_;
139 return qq!sub {\n!. ( $args{no_mangling} ? $line : $self->mangle_line($line) ).qq!\n}\n!;
911a1c24 140}
141
142sub mangle_line {
143 my ($self, $line) = @_;
144 return $line;
145}
146
afe61f9c 147sub execute {
48ddfeae 148 my ($self, $to_exec, @args) = @_;
149 my @ret = eval { $to_exec->(@args) };
150 return $self->error_return("Runtime error", $@) if $@;
afe61f9c 151 return @ret;
152}
153
911a1c24 154sub error_return {
155 my ($self, $type, $error) = @_;
e22aa835 156 return Devel::REPL::Error->new( type => $type, message => $error );
911a1c24 157}
158
afe61f9c 159sub print {
160 my ($self, @ret) = @_;
161 my $fh = $self->out_fh;
59aedffc 162 no warnings 'uninitialized';
afe61f9c 163 print $fh "@ret";
a66625d6 164 print $fh "\n" if $self->term->ReadLine =~ /Gnu/;
afe61f9c 165}
166
59aedffc 167=head1 NAME
168
169Devel::REPL - a modern perl interactive shell
170
171=head1 SYNOPSIS
172
173 my $repl = Devel::REPL->new;
174 $repl->load_plugin($_) for qw(History LexEnv);
175 $repl->run
176
177Alternatively, use the 're.pl' script installed with the distribution
178
950232b2 179 system$ re.pl
180
408564af 181=head1 DESCRIPTION
182
183This is an interactive shell for Perl, commonly known as a REPL - Read,
184Evaluate, Print, Loop. The shell provides for rapid development or testing
185of code without the need to create a temporary source code file.
186
187Through a plugin system, many features are available on demand. You can also
188tailor the environment through the use of profiles and run control files, for
189example to pre-load certain Perl modules when working on a particular project.
190
191=head1 USAGE
192
193To start a shell, follow one of the examples in the L</"SYNOPSIS"> above.
194
195Once running, the shell accepts and will attempt to execute any code given. If
196the code executes successfully you'll be shown the result, otherwise an error
197message will be returned. Here are a few examples:
198
199 $_ print "Hello, world!\n"
200 Hello, world!
201 1
202 $_ nosuchfunction
203 Compile error: Bareword "nosuchfunction" not allowed while "strict subs" in use at (eval 130) line 5.
20d9434d 204
205 $_
408564af 206
207In the first example above you see the output of the command (C<Hello,
208world!>), if any, and then the return value of the statement (C<1>). Following
209that example, an error is returned when the execution of some code fails.
210
211Note that the lack of semicolon on the end is not a mistake - the code is
212run inside a Block structure (to protect the REPL in case the code blows up),
213which means a single statement doesn't require the semicolon. You can add one
214if you like, though.
215
6aa58492 216If you followed the first example in the L</"SYNOPSIS"> above, you'll have the
408564af 217History and LexEnv plugins loaded (and there are many more available).
218Although the shell might support "up-arrow" history, the History plugin adds
219"bang" history to that so you can re-execute chosen commands (with e.g.
220C<!53>). The LexEnv plugin ensures that lexical variables declared with the
221C<my> keyword will automatically persist between statements executed in the
222REPL shell.
223
224When you C<use> any Perl module, the C<import()> will work as expected - the
225exported functions from that module are available for immediate use:
226
227 $_ carp "I'm dieeeing!\n"
228 String found where operator expected at (eval 129) line 5, near "carp "I'm dieeeing!\n""
229 (Do you need to predeclare carp?)
230 Compile error: syntax error at (eval 129) line 5, near "carp "I'm dieeeing!\n""
231 BEGIN not safe after errors--compilation aborted at (eval 129) line 5.
20d9434d 232
233 $_ use Carp
234
408564af 235 $_ carp "I'm dieeeing!\n"
236 I'm dieeeing!
237 at /usr/share/perl5/Lexical/Persistence.pm line 327
238 1
20d9434d 239 $_
408564af 240
73d11b24 241To quit from the shell, hit C<Ctrl+D> or C<Ctrl+C>.
242
243 MSWin32 NOTE: control keys won't work if TERM=dumb
244 because readline functionality will be disabled.
245
408564af 246
247=head2 Run Control Files
248
249For particular projects you might well end up running the same commands each
250time the REPL shell starts up - loading Perl modules, setting configuration,
251and so on. A run control file lets you have this done automatically, and you
252can have multiple files for different projects.
253
254By default the C<re.pl> program looks for C<< $HOME/.re.pl/repl.rc >>, and
255runs whatever code is in there as if you had entered it at the REPL shell
256yourself.
257
258To set a new run control file that's also in that directory, pass it as a
259filename like so:
260
261 system$ re.pl --rcfile myproject.pc
262
263If the filename happens to contain a forwardslash, then it's used absolutely,
264or realive to the current working directory:
265
266 system$ re.pl --rcfile /path/to/my/project/repl.rc
267
268Within the run control file you might want to load plugins. This is covered in
269L</"The REPL shell object"> section, below.
270
271=head2 Profiles
272
273To allow for the sharing of run control files, you can fashion them into a
274Perl module for distribution (perhaps via the CPAN). For more information on
275this feature, please see the L<Devel::REPL::Profile> manual page.
276
277A default profile ships with C<Devel::REPL>; it loads the following plugins:
278
279=over 4
280
281=item *
282
283L<Devel::REPL::Plugin::History>
284
285=item *
286
287L<Devel::REPL::Plugin::LexEnv>
288
289=item *
290
291L<Devel::REPL::Plugin::DDS>
292
293=item *
294
295L<Devel::REPL::Plugin::Packages>
296
297=item *
298
299L<Devel::REPL::Plugin::Commands>
300
301=item *
302
303L<Devel::REPL::Plugin::MultiLine::PPI>
304
071c41fa 305=item *
306
307L<Devel::REPL::Plugin::Colors>
308
309=item *
310
311L<Devel::REPL::Plugin::Completion>
312
313=item *
314
315L<Devel::REPL::Plugin::CompletionDriver::INC>
316
317=item *
318
319L<Devel::REPL::Plugin::CompletionDriver::LexEnv>
320
321=item *
322
323L<Devel::REPL::Plugin::CompletionDriver::Keywords>
324
325=item *
326
327L<Devel::REPL::Plugin::CompletionDriver::Methods>
328
329=item *
330
331L<Devel::REPL::Plugin::ReadlineHistory>
332
408564af 333=back
334
335=head2 Plugins
336
337Plugins are a way to add funcionality to the REPL shell, and take advantage of
338C<Devel::REPL> being based on the L<Moose> object system for Perl 5. This
339means it's simple to 'hook into' many steps of the R-E-P-L process. Plugins
340can change the way commands are interpreted, or the way their results are
341output, or even add commands to the shell environment.
342
343A number of plugins ship with C<Devel::REPL>, and more are available on the
344CPAN. Some of the shipped plugins are loaded in the default profile, mentioned
cfb85b27 345above. These plugins can be loaded in your C<< $HOME/.re.pl/repl.rc >> like:
346
347 load_plugin qw( CompletionDriver::Global DumpHistory );
408564af 348
349Writing your own plugins is not difficult, and is discussed in the
350L<Devel::REPL::Plugin> manual page, along with links to the manual pages of
351all the plugins shipped with C<Devel::REPL>.
352
353=head2 The REPL shell object
354
355From time to time you'll want to interact with or manipulate the
356C<Devel::REPL> shell object itself; that is, the instance of the shell you're
357currently running.
358
359The object is always available through the C<$_REPL> variable. One common
360requirement is to load an additional plugin, after your profile and run
361control files have already been executed:
362
363 $_ $_REPL->load_plugin('Timing');
364 1
365 $_ print "Hello again, world!\n"
366 Hello again, world!
367 Took 0.00148296356201172 seconds.
368 1
369 $_
370
371=head1 REQUIREMENTS
372
373In addition to the contents of the standard Perl distribution, you will need
374the following:
375
376=over 4
377
378=item *
379
73d11b24 380L<Moose> >= 0.74
6aa58492 381
382=item *
383
73d11b24 384L<MooseX::Getopt> >= 0.18
408564af 385
386=item *
387
e2d0b019 388L<namespace::sweep>
408564af 389
390=item *
391
392L<File::HomeDir>
393
394=item *
395
ab213f1f 396L<Task::Weaken>
397
73d11b24 398=item *
399
400L<B::Concise>
401
402=item *
403
404L<Term::ANSIColor>
405
406=item *
407
408L<Devel::Peek>
409
ab213f1f 410=back
411
412Optionally, some plugins if installed will require the following modules:
413
414=over 4
415
416=item *
417
418L<PPI>
408564af 419
420=item *
421
6aa58492 422L<Data::Dump::Streamer>
408564af 423
424=item *
425
73d11b24 426L<Data::Dumper::Concise>
427
428=item *
429
ab213f1f 430L<File::Next>
408564af 431
432=item *
433
73d11b24 434L<Sys::SigAction>
435
436=item *
437
408564af 438L<B::Keywords>
439
440=item *
441
ab213f1f 442L<Lexical::Persistence>
408564af 443
444=item *
445
446L<App::Nopaste>
447
ab213f1f 448=item *
449
450L<Module::Refresh>
451
408564af 452=back
453
59aedffc 454=head1 AUTHOR
455
456Matt S Trout - mst (at) shadowcatsystems.co.uk (L<http://www.shadowcatsystems.co.uk/>)
457
c1d5d500 458=head1 CONTRIBUTORS
459
460=over 4
461
462=item Stevan Little - stevan (at) iinteractive.com
463
464=item Alexis Sukrieh - sukria+perl (at) sukria.net
465
466=item epitaph
467
468=item mgrimes - mgrimes (at) cpan dot org
469
470=item Shawn M Moore - sartak (at) gmail.com
471
ab213f1f 472=item Oliver Gorwits - oliver on irc.perl.org
6aa58492 473
da4881b1 474=item Andrew Moore - C<< <amoore@cpan.org> >>
475
88d6bf36 476=item Norbert Buchmuller C<< <norbi@nix.hu> >>
477
d13037d5 478=item Dave Houston C<< <dhouston@cpan.org> >>
479
73d11b24 480=item Chris Marshall
481
c1d5d500 482=back
483
59aedffc 484=head1 LICENSE
485
486This library is free software under the same terms as perl itself
487
488=cut
489
afe61f9c 4901;