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6aa58492 1NAME
2 Devel::REPL - a modern perl interactive shell
3
4SYNOPSIS
5 my $repl = Devel::REPL->new;
6 $repl->load_plugin($_) for qw(History LexEnv);
7 $repl->run
8
9 Alternatively, use the 're.pl' script installed with the distribution
10
11 system$ re.pl
12
13DESCRIPTION
14 This is an interactive shell for Perl, commonly known as a REPL - Read,
15 Evaluate, Print, Loop. The shell provides for rapid development or
16 testing of code without the need to create a temporary source code file.
17
18 Through a plugin system, many features are available on demand. You can
19 also tailor the environment through the use of profiles and run control
20 files, for example to pre-load certain Perl modules when working on a
21 particular project.
22
23USAGE
24 To start a shell, follow one of the examples in the "SYNOPSIS" above.
25
26 Once running, the shell accepts and will attempt to execute any code
27 given. If the code executes successfully you'll be shown the result,
28 otherwise an error message will be returned. Here are a few examples:
29
73d11b24 30 $_ print "Hello, world!\n"
31 Hello, world!
32 1
33 $_ nosuchfunction
34 Compile error: Bareword "nosuchfunction" not allowed while "strict subs" in use at (eval 130) line 5.
35
36 $_
6aa58492 37
38 In the first example above you see the output of the command ("Hello,
39 world!"), if any, and then the return value of the statement (1).
40 Following that example, an error is returned when the execution of some
41 code fails.
42
43 Note that the lack of semicolon on the end is not a mistake - the code
44 is run inside a Block structure (to protect the REPL in case the code
45 blows up), which means a single statement doesn't require the semicolon.
46 You can add one if you like, though.
47
48 If you followed the first example in the "SYNOPSIS" above, you'll have
49 the History and LexEnv plugins loaded (and there are many more
50 available). Although the shell might support "up-arrow" history, the
51 History plugin adds "bang" history to that so you can re-execute chosen
52 commands (with e.g. "!53"). The LexEnv plugin ensures that lexical
53 variables declared with the "my" keyword will automatically persist
54 between statements executed in the REPL shell.
55
56 When you "use" any Perl module, the "import()" will work as expected -
57 the exported functions from that module are available for immediate use:
58
73d11b24 59 $_ carp "I'm dieeeing!\n"
60 String found where operator expected at (eval 129) line 5, near "carp "I'm dieeeing!\n""
61 (Do you need to predeclare carp?)
62 Compile error: syntax error at (eval 129) line 5, near "carp "I'm dieeeing!\n""
63 BEGIN not safe after errors--compilation aborted at (eval 129) line 5.
64
65 $_ use Carp
66
67 $_ carp "I'm dieeeing!\n"
68 I'm dieeeing!
69 at /usr/share/perl5/Lexical/Persistence.pm line 327
70 1
71 $_
1ca46867 72
73 To quit from the shell, hit "Ctrl+D" or "Ctrl+C".
6aa58492 74
73d11b24 75 MSWin32 NOTE: control keys won't work if TERM=dumb
76 because readline functionality will be disabled.
6aa58492 77
78 Run Control Files
79 For particular projects you might well end up running the same commands
80 each time the REPL shell starts up - loading Perl modules, setting
81 configuration, and so on. A run control file lets you have this done
82 automatically, and you can have multiple files for different projects.
83
84 By default the "re.pl" program looks for "$HOME/.re.pl/repl.rc", and
85 runs whatever code is in there as if you had entered it at the REPL
86 shell yourself.
87
88 To set a new run control file that's also in that directory, pass it as
89 a filename like so:
90
73d11b24 91 system$ re.pl --rcfile myproject.pc
6aa58492 92
93 If the filename happens to contain a forwardslash, then it's used
73d11b24 94 absolutely, or realive to the current working directory:
6aa58492 95
73d11b24 96 system$ re.pl --rcfile /path/to/my/project/repl.rc
6aa58492 97
98 Within the run control file you might want to load plugins. This is
99 covered in "The REPL shell object" section, below.
100
101 Profiles
102 To allow for the sharing of run control files, you can fashion them into
103 a Perl module for distribution (perhaps via the CPAN). For more
104 information on this feature, please see the Devel::REPL::Profile manual
105 page.
106
107 A default profile ships with "Devel::REPL"; it loads the following
108 plugins:
109
110 * Devel::REPL::Plugin::History
111
112 * Devel::REPL::Plugin::LexEnv
113
114 * Devel::REPL::Plugin::DDS
115
116 * Devel::REPL::Plugin::Packages
117
118 * Devel::REPL::Plugin::Commands
119
120 * Devel::REPL::Plugin::MultiLine::PPI
121
122 Plugins
123 Plugins are a way to add funcionality to the REPL shell, and take
124 advantage of "Devel::REPL" being based on the Moose object system for
125 Perl 5. This means it's simple to 'hook into' many steps of the R-E-P-L
126 process. Plugins can change the way commands are interpreted, or the way
127 their results are output, or even add commands to the shell environment.
128
129 A number of plugins ship with "Devel::REPL", and more are available on
130 the CPAN. Some of the shipped plugins are loaded in the default profile,
131 mentioned above.
132
73d11b24 133 Writing your own plugins is not difficult, and is discussed in the
134 Devel::REPL::Plugin manual page, along with links to the manual pages of
135 all the plugins shipped with "Devel::REPL".
6aa58492 136
137 The REPL shell object
138 From time to time you'll want to interact with or manipulate the
139 "Devel::REPL" shell object itself; that is, the instance of the shell
140 you're currently running.
141
142 The object is always available through the $_REPL variable. One common
143 requirement is to load an additional plugin, after your profile and run
144 control files have already been executed:
145
146 $_ $_REPL->load_plugin('Timing');
147 1
148 $_ print "Hello again, world!\n"
149 Hello again, world!
150 Took 0.00148296356201172 seconds.
151 1
152 $_
153
154REQUIREMENTS
155 In addition to the contents of the standard Perl distribution, you will
156 need the following:
157
73d11b24 158 * Moose >= 0.74
6aa58492 159
160 * MooseX::Object::Pluggable >= 0.0009
161
73d11b24 162 * MooseX::Getopt >= 0.18
6aa58492 163
73d11b24 164 * MooseX::AttributeHelpers >= 0.16
6aa58492 165
166 * namespace::clean
167
168 * File::HomeDir
169
ab213f1f 170 * Task::Weaken
6aa58492 171
73d11b24 172 * B::Concise
173
174 * Term::ANSIColor
175
176 * Devel::Peek
177
ab213f1f 178 Optionally, some plugins if installed will require the following
179 modules:
6aa58492 180
181 * PPI
182
ab213f1f 183 * Data::Dump::Streamer
184
73d11b24 185 * Data::Dumper::Concise
186
ab213f1f 187 * File::Next
188
73d11b24 189 * Sys::SigAction
190
6aa58492 191 * B::Keywords
192
ab213f1f 193 * Lexical::Persistence
6aa58492 194
195 * App::Nopaste
196
ab213f1f 197 * Module::Refresh
198
6aa58492 199AUTHOR
200 Matt S Trout - mst (at) shadowcatsystems.co.uk
201 (<http://www.shadowcatsystems.co.uk/>)
202
203CONTRIBUTORS
73d11b24 204 Stevan Little - stevan (at) iinteractive.com
6aa58492 205 Alexis Sukrieh - sukria+perl (at) sukria.net
206 epitaph
73d11b24 207 mgrimes - mgrimes (at) cpan dot org
208 Shawn M Moore - sartak (at) gmail.com
ab213f1f 209 Oliver Gorwits - oliver on irc.perl.org
73d11b24 210 Andrew Moore - "<amoore@cpan.org>"
211 Norbert Buchmuller "<norbi@nix.hu>"
212 Dave Houston "<dhouston@cpan.org>"
1ca46867 213 Chris Marshall
6aa58492 214
215LICENSE
216 This library is free software under the same terms as perl itself
217