From: oliver Date: Mon, 9 Jun 2008 17:51:22 +0000 (+0000) Subject: add expanded documentation X-Git-Tag: v1.003015~86 X-Git-Url: http://git.shadowcat.co.uk/gitweb/gitweb.cgi?a=commitdiff_plain;h=408564af8826ffeb3647bbd482e43a606cbdade8;p=p5sagit%2FDevel-REPL.git add expanded documentation git-svn-id: http://dev.catalyst.perl.org/repos/bast/trunk/Devel-REPL@4477 bd8105ee-0ff8-0310-8827-fb3f25b6796d --- diff --git a/lib/Devel/REPL.pm b/lib/Devel/REPL.pm index 3c986cb..7c341de 100644 --- a/lib/Devel/REPL.pm +++ b/lib/Devel/REPL.pm @@ -157,6 +157,215 @@ Alternatively, use the 're.pl' script installed with the distribution system$ re.pl +=head1 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. + +=head1 USAGE + +To start a shell, follow one of the examples in the L 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 (C), if any, and then the return value of the statement (C<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 L above, you'l 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. +C). The LexEnv plugin ensures that lexical variables declared with the +C keyword will automatically persist between statements executed in the +REPL shell. + +When you C any Perl module, the C 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 C or C. + +=head2 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 C program looks for C<< $HOME/.re.pl/repl.rc >>, and +runs whatever code is in there as if you had entered it at the REPL shell +yourself. + +To set a new run control file that's also in that directory, pass it as a +filename like so: + + system$ re.pl --rcfile myproject.pc + +If the filename happens to contain a forwardslash, then it's used absolutely, +or realive 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 +L section, below. + +=head2 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 L manual page. + +A default profile ships with C; it loads the following plugins: + +=over 4 + +=item * + +L + +=item * + +L + +=item * + +L + +=item * + +L + +=item * + +L + +=item * + +L + +=back + +=head2 Plugins + +Plugins are a way to add funcionality to the REPL shell, and take advantage of +C being based on the L 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 C, 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, and is discussed in the +L manual page, along with links to the manual pages of +all the plugins shipped with C. + +=head2 The REPL shell object + +From time to time you'll want to interact with or manipulate the +C shell object itself; that is, the instance of the shell you're +currently running. + +The object is always available through the C<$_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 + $_ + +=head1 REQUIREMENTS + +In addition to the contents of the standard Perl distribution, you will need +the following: + +=over 4 + +=item * + +L >= 0.38 + +=item * + +L >= 0.0007 + +=item * + +L + +=item * + +L + +=item * + +L + +=item * + +L + +=item * + +L + +=item * + +L + +=item * + +L + +=item * + +L + +=item * + +L + +=back + =head1 AUTHOR Matt S Trout - mst (at) shadowcatsystems.co.uk (L)