NAME¶

Devel::REPL - A modern perl interactive shell

VERSION¶

version 1.003029

SYNOPSIS¶

  my $repl = Devel::REPL->new;
  $repl->load_plugin($_) for qw(History LexEnv);
  $repl->run

Alternatively, use the 're.pl' script installed with the distribution

  system$ re.pl

DESCRIPTION¶

This is an interactive shell for Perl, commonly known as a REPL - Read, Evaluate, Print, Loop. The shell provides for rapid development or testing of code without the need to create a temporary source code file.

Through a plugin system, many features are available on demand. You can also tailor the environment through the use of profiles and run control files, for example to pre-load certain Perl modules when working on a particular project.

USAGE¶

To start a shell, follow one of the examples in the "SYNOPSIS" above.

Once running, the shell accepts and will attempt to execute any code given. If the code executes successfully you'll be shown the result, otherwise an error message will be returned. Here are a few examples:

 $_ print "Hello, world!\n"
 Hello, world!
 1
 $_ nosuchfunction
 Compile error: Bareword "nosuchfunction" not allowed while "strict subs" in use at (eval 130) line 5.
 $_

In the first example above you see the output of the command ("Hello, world!"), if any, and then the return value of the statement (1). Following that example, an error is returned when the execution of some code fails.

Note that the lack of semicolon on the end is not a mistake - the code is run inside a Block structure (to protect the REPL in case the code blows up), which means a single statement doesn't require the semicolon. You can add one if you like, though.

If you followed the first example in the "SYNOPSIS" above, you'll have the History and LexEnv plugins loaded (and there are many more available). Although the shell might support "up-arrow" history, the History plugin adds "bang" history to that so you can re-execute chosen commands (with e.g. "!53"). The LexEnv plugin ensures that lexical variables declared with the "my" keyword will automatically persist between statements executed in the REPL shell.

When you "use" any Perl module, the "import()" will work as expected - the exported functions from that module are available for immediate use:

 $_ carp "I'm dieeeing!\n"
 String found where operator expected at (eval 129) line 5, near "carp "I'm dieeeing!\n""
         (Do you need to predeclare carp?)
 Compile error: syntax error at (eval 129) line 5, near "carp "I'm dieeeing!\n""
 BEGIN not safe after errors--compilation aborted at (eval 129) line 5.
 $_ use Carp
 $_ carp "I'm dieeeing!\n"
 I'm dieeeing!
  at /usr/share/perl5/Lexical/Persistence.pm line 327
 1
 $_

To quit from the shell, hit "Ctrl+D" or "Ctrl+C".

  MSWin32 NOTE: control keys won't work if TERM=dumb
  because readline functionality will be disabled.

 system$ re.pl --rcfile myproject.pc

 system$ re.pl --rcfile /path/to/my/project/repl.rc

  load_plugin qw( CompletionDriver::Global DumpHistory );

 $_ $_REPL->load_plugin('Timing');
 1
 $_ print "Hello again, world!\n"
 Hello again, world!
 Took 0.00148296356201172 seconds.
 1
 $_

OPTIONAL FEATURES¶

In addition to the prerequisites declared in this distribution, which should be automatically installed by your CPAN client, there are a number of optional features, used by additional plugins. You can install any of these features by installing this distribution interactively (e.g. "cpanm --interactive Devel::REPL").

• Completion plugin - extensible tab completion
• DDS plugin - better format results with Data::Dump::Streamer
• DDC plugin - even better format results with Data::Dumper::Concise
• INC completion driver - tab complete module names in use and require
• Interrupt plugin - traps SIGINT to kill long-running lines
• Keywords completion driver - tab complete Perl keywords and operators
• LexEnv plugin - variables declared with "my" persist between statements
• MultiLine::PPI plugin - continue reading lines until all blocks are closed
• Nopaste plugin - upload a session\'s input and output to a Pastebin
• PPI plugin - PPI dumping of Perl code
• Refresh plugin - automatically reload libraries with Module::Refresh

SEE ALSO¶

•

A comparison of various REPLs <https://www.shadowcat.co.uk/blog/matt-s-trout/mstpan-17/>

SUPPORT¶

Bugs may be submitted through the RT bug tracker <https://rt.cpan.org/Public/Dist/Display.html?Name=Devel-REPL> (or bug-Devel-REPL@rt.cpan.org <mailto:bug-Devel-REPL@rt.cpan.org>).

There is also an irc channel available for users of this distribution, at "#devel" on "irc.perl.org" <irc://irc.perl.org/#devel-repl>.

AUTHOR¶

Matt S Trout - mst (at) shadowcatsystems.co.uk (<http://www.shadowcatsystems.co.uk/>)

CONTRIBUTORS¶

• Karen Etheridge <ether@cpan.org>
• Shawn M Moore <code@sartak.org>
• Chris Marshall <devel.chm.01@gmail.com>
• Matt S Trout <mst@shadowcat.co.uk>
• Oliver Gorwits <oliver@cpan.org>
• יובל קוג'מן (Yuval Kogman) <nothingmuch@woobling.org>
• Arthur Axel 'fREW' Schmidt <frioux@gmail.com>
• Alexis Sukrieh <sukria+perl@sukria.net>
• Andrew Moore <amoore@cpan.org>
• epitaph <unknown>
• Jesse Luehrs <doy@tozt.net>
• Norbert Buchmuller <norbi@nix.hu>
• Tomas Doran (t0m) <bobtfish@bobtfish.net>
• Dagfinn Ilmari Mannsåker <ilmari@ilmari.org>
• Dave Houston <dhouston@cpan.org>
• Zakariyya Mughal <zaki.mughal@gmail.com>
• Ash Berlin <ash_github@firemirror.com>
• Justin Hunter <justin.d.hunter@gmail.com>
• mgrimes <mgrimes@cpan.org>
• naquad <naquad@bd8105ee-0ff8-0310-8827-fb3f25b6796d>
• Ryan Niebur <ryan@debian.org>
• Stevan Little <stevan.little@iinteractive.com>

COPYRIGHT AND LICENCE¶

This software is copyright (c) 2007 by Matt S Trout - mst (at) shadowcatsystems.co.uk (<http://www.shadowcatsystems.co.uk/>).

This is free software; you can redistribute it and/or modify it under the same terms as the Perl 5 programming language system itself.