Minor cleanup/edit of README

[p5sagit/Devel-REPL.git] / README

NAME
    Devel::REPL - a modern perl interactive shell

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.

  Run Control Files
    For particular projects you might well end up running the same commands
    each time the REPL shell starts up - loading Perl modules, setting
    configuration, and so on. A run control file lets you have this done
    automatically, and you can have multiple files for different projects.

    By default the "re.pl" program looks for "$HOME/.re.pl/repl.rc", and
    runs whatever code is in there as if you had entered it at the REPL
    shell yourself.

    To set a new run control file that's also in that directory, pass it as
    a filename like so:

      system$ re.pl --rcfile myproject.pc

    If the filename happens to contain a forwardslash, then it's used
    absolutely, or relative to the current working directory:

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

    Within the run control file you might want to load plugins. This is
    covered in "The REPL shell object" section, below.

  Profiles
    To allow for the sharing of run control files, you can fashion them into
    a Perl module for distribution (perhaps via the CPAN). For more
    information on this feature, please see the Devel::REPL::Profile manual
    page.

    A default profile ships with "Devel::REPL"; it loads the following
    plugins:

    *   Devel::REPL::Plugin::History

    *   Devel::REPL::Plugin::LexEnv

    *   Devel::REPL::Plugin::DDS

    *   Devel::REPL::Plugin::Packages

    *   Devel::REPL::Plugin::Commands

    *   Devel::REPL::Plugin::MultiLine::PPI

  Plugins
    Plugins are a way to add funcionality to the REPL shell, and take
    advantage of "Devel::REPL" being based on the Moose object system for
    Perl 5. This means it's simple to 'hook into' many steps of the R-E-P-L
    process. Plugins can change the way commands are interpreted, or the way
    their results are output, or even add commands to the shell environment.

    A number of plugins ship with "Devel::REPL", and more are available on
    the CPAN. Some of the shipped plugins are loaded in the default profile,
    mentioned above.

    Writing your own plugins is not difficult once you understand all about
    Moose and Moose Roles.  A Devel::REPL::Plugin manual page is planned but
    not yet written.

  The REPL shell object
    From time to time you'll want to interact with or manipulate the
    "Devel::REPL" shell object itself; that is, the instance of the shell
    you're currently running.

    The object is always available through the $_REPL variable. One common
    requirement is to load an additional plugin, after your profile and run
    control files have already been executed:

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

REQUIREMENTS
    In addition to the contents of the standard Perl distribution, you will
    need the following:

    *   Moose >= 0.64

    *   MooseX::Object::Pluggable >= 0.0009

    *   MooseX::Getopt >= 0.15

    *   MooseX::AttributeHelpers >= 0.14

    *   namespace::clean

    *   File::HomeDir

    *   Task::Weaken

    Optionally, some plugins if installed will require the following
    modules:

    *   PPI

    *   Data::Dump::Streamer

    *   File::Next

    *   B::Keywords

    *   Lexical::Persistence

    *   App::Nopaste

    *   Module::Refresh

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

CONTRIBUTORS
    Stevan Little  - stevan (at) iinteractive.com
    Alexis Sukrieh - sukria+perl (at) sukria.net
    epitaph
    mgrimes        - mgrimes (at) cpan (dot) org
    Shawn M Moore  - sartak (at) gmail.com
    Oliver Gorwits - oliver on irc.perl.org
    Chris Marshall

LICENSE
    This library is free software under the same terms as perl itself