NAME
Perl::Critic - Critique Perl source code for best-practices.
SYNOPSIS
use Perl::Critic;
my $file = shift;
my $critic = Perl::Critic->new();
my @violations = $critic->critique($file);
print @violations;
DESCRIPTION
Perl::Critic is an extensible framework for creating and applying coding
standards to Perl source code. Essentially, it is a static source code
analysis engine. Perl::Critic is distributed with a number of
Perl::Critic::Policy modules that attempt to enforce various coding
guidelines. Most Policy modules are based on Damian Conway's book Perl
Best Practices. However, Perl::Critic is not limited to PBP and will
even support Policies that contradict Conway. You can enable, disable,
and customize those Polices through the Perl::Critic interface. You can
also create new Policy modules that suit your own tastes.
For a command-line interface to Perl::Critic, see the documentation for
perlcritic. If you want to integrate Perl::Critic with your build
process, Test::Perl::Critic provides an interface that is suitable for
test programs. Also, Test::Perl::Critic::Progressive is useful for
gradually applying coding standards to legacy code. For the ultimate
convenience (at the expense of some flexibility) see the criticism
pragma.
Win32 and ActivePerl users can find PPM distributions of Perl::Critic at
<http://theoryx5.uwinnipeg.ca/ppms/> and Alexandr Ciornii's downloadable
executable at <http://chorny.net/perl/perlcritic.html>.
If you'd like to try Perl::Critic without installing anything, there is
a web-service available at <http://perlcritic.com>. The web-service does
not yet support all the configuration features that are available in the
native Perl::Critic API, but it should give you a good idea of what it
does. You can also invoke the perlcritic web-service from the
command-line by doing an HTTP-post, such as one of these:
$> lwp-request -m POST http://perlcritic.com/perl/critic.pl < MyModule.pm
$> wget -q -O - --post-file=MyModule.pm http://perlcritic.com/perl/critic.pl
$> curl --data @MyModule.pm http://perlcritic.com/perl/critic.pl
Please note that the perlcritic web-service is still alpha code. The URL
and interface to the service are subject to change.
Also, ActivePerl includes a very slick graphical interface to
Perl-Critic called "perlcritic-gui". You can get a free community
edition of ActivePerl from <http://www.activestate.com>.
INTERFACE SUPPORT
This is considered to be a public class. Any changes to its interface
will go through a deprecation cycle.
CONSTRUCTOR
"new( [ -profile => $FILE, -severity => $N, -theme => $string, -include
=> \@PATTERNS, -exclude => \@PATTERNS, -top => $N, -only => $B,
-profile-strictness => $PROFILE_STRICTNESS_{WARN|FATAL|QUIET}, -force =>
$B, -verbose => $N ], -color => $B, -pager => $string, -allow-unsafe =>
$B, -criticism-fatal => $B)"
"new()"
Returns a reference to a new Perl::Critic object. Most arguments are
just passed directly into Perl::Critic::Config, but I have described
them here as well. The default value for all arguments can be
defined in your .perlcriticrc file. See the "CONFIGURATION" section
for more information about that. All arguments are optional
key-value pairs as follows:
-profile is a path to a configuration file. If $FILE is not defined,
Perl::Critic::Config attempts to find a .perlcriticrc configuration
file in the current directory, and then in your home directory.
Alternatively, you can set the "PERLCRITIC" environment variable to
point to a file in another location. If a configuration file can't
be found, or if $FILE is an empty string, then all Policies will be
loaded with their default configuration. See "CONFIGURATION" for
more information.
-severity is the minimum severity level. Only Policy modules that
have a severity greater than $N will be applied. Severity values are
integers ranging from 1 (least severe violations) to 5 (most severe
violations). The default is 5. For a given "-profile", decreasing
the "-severity" will usually reveal more Policy violations. You can
set the default value for this option in your .perlcriticrc file.
Users can redefine the severity level for any Policy in their
.perlcriticrc file. See "CONFIGURATION" for more information.
If it is difficult for you to remember whether severity "5" is the
most or least restrictive level, then you can use one of these named
values:
SEVERITY NAME ...is equivalent to... SEVERITY NUMBER
--------------------------------------------------------
-severity => 'gentle' -severity => 5
-severity => 'stern' -severity => 4
-severity => 'harsh' -severity => 3
-severity => 'cruel' -severity => 2
-severity => 'brutal' -severity => 1
The names reflect how severely the code is criticized: a "gentle"
criticism reports only the most severe violations, and so on down to
a "brutal" criticism which reports even the most minor violations.
-theme is special expression that determines which Policies to apply
based on their respective themes. For example, the following would
load only Policies that have a 'bugs' AND 'pbp' theme:
my $critic = Perl::Critic->new( -theme => 'bugs && pbp' );
Unless the "-severity" option is explicitly given, setting "-theme"
silently causes the "-severity" to be set to 1. You can set the
default value for this option in your .perlcriticrc file. See the
"POLICY THEMES" section for more information about themes.
-include is a reference to a list of string @PATTERNS. Policy
modules that match at least one "m/$PATTERN/ixms" will always be
loaded, irrespective of all other settings. For example:
my $critic = Perl::Critic->new(-include => ['layout'] -severity => 4);
This would cause Perl::Critic to apply all the "CodeLayout::*"
Policy modules even though they have a severity level that is less
than 4. You can set the default value for this option in your
.perlcriticrc file. You can also use "-include" in conjunction with
the "-exclude" option. Note that "-exclude" takes precedence over
"-include" when a Policy matches both patterns.
-exclude is a reference to a list of string @PATTERNS. Policy
modules that match at least one "m/$PATTERN/ixms" will not be
loaded, irrespective of all other settings. For example:
my $critic = Perl::Critic->new(-exclude => ['strict'] -severity => 1);
This would cause Perl::Critic to not apply the "RequireUseStrict"
and "ProhibitNoStrict" Policy modules even though they have a
severity level that is greater than 1. You can set the default value
for this option in your .perlcriticrc file. You can also use
"-exclude" in conjunction with the "-include" option. Note that
"-exclude" takes precedence over "-include" when a Policy matches
both patterns.
-single-policy is a string "PATTERN". Only one policy that matches
"m/$PATTERN/ixms" will be used. Policies that do not match will be
excluded. This option has precedence over the "-severity", "-theme",
"-include", "-exclude", and "-only" options. You can set the default
value for this option in your .perlcriticrc file.
-top is the maximum number of Violations to return when ranked by
their severity levels. This must be a positive integer. Violations
are still returned in the order that they occur within the file.
Unless the "-severity" option is explicitly given, setting "-top"
silently causes the "-severity" to be set to 1. You can set the
default value for this option in your .perlcriticrc file.
-only is a boolean value. If set to a true value, Perl::Critic will
only choose from Policies that are mentioned in the user's profile.
If set to a false value (which is the default), then Perl::Critic
chooses from all the Policies that it finds at your site. You can
set the default value for this option in your .perlcriticrc file.
-profile-strictness is an enumerated value, one of
"$PROFILE_STRICTNESS_WARN" in Perl::Critic::Utils::Constants (the
default), "$PROFILE_STRICTNESS_FATAL" in
Perl::Critic::Utils::Constants, and "$PROFILE_STRICTNESS_QUIET" in
Perl::Critic::Utils::Constants. If set to
"$PROFILE_STRICTNESS_FATAL" in Perl::Critic::Utils::Constants,
Perl::Critic will make certain warnings about problems found in a
.perlcriticrc or file specified via the -profile option fatal. For
example, Perl::Critic normally only "warn"s about profiles referring
to non-existent Policies, but this value makes this situation fatal.
Correspondingly, "$PROFILE_STRICTNESS_QUIET" in
Perl::Critic::Utils::Constants makes Perl::Critic shut up about
these things.
-force is a boolean value that controls whether Perl::Critic
observes the magical "## no critic" annotations in your code. If set
to a true value, Perl::Critic will analyze all code. If set to a
false value (which is the default) Perl::Critic will ignore code
that is tagged with these annotations. See "BENDING THE RULES" for
more information. You can set the default value for this option in
your .perlcriticrc file.
-verbose can be a positive integer (from 1 to 11), or a literal
format specification. See Perl::Critic::Violation for an explanation
of format specifications. You can set the default value for this
option in your .perlcriticrc file.
-unsafe directs Perl::Critic to allow the use of Policies that are
marked as "unsafe" by the author. Such policies may compile
untrusted code or do other nefarious things.
-color and -pager are not used by Perl::Critic but is provided for
the benefit of perlcritic.
-criticism-fatal is not used by Perl::Critic but is provided for the
benefit of criticism.
-color-severity-highest, -color-severity-high,
-color-severity-medium, -color-severity-low, and
-color-severity-lowest are not used by Perl::Critic, but are
provided for the benefit of perlcritic. Each is set to the
Term::ANSIColor color specification to be used to display violations
of the corresponding severity.
-files-with-violations and -files-without-violations are not used by
Perl::Critic, but are provided for the benefit of perlcritic, to
cause only the relevant filenames to be displayed.
METHODS
"critique( $source_code )"
Runs the $source_code through the Perl::Critic engine using all the
Policies that have been loaded into this engine. If $source_code is
a scalar reference, then it is treated as a string of actual Perl
code. If $source_code is a reference to an instance of
PPI::Document, then that instance is used directly. Otherwise, it is
treated as a path to a local file containing Perl code. This method
returns a list of Perl::Critic::Violation objects for each violation
of the loaded Policies. The list is sorted in the order that the
Violations appear in the code. If there are no violations, this
method returns an empty list.
"add_policy( -policy => $policy_name, -params => \%param_hash )"
Creates a Policy object and loads it into this Critic. If the object
cannot be instantiated, it will throw a fatal exception. Otherwise,
it returns a reference to this Critic.
-policy is the name of a Perl::Critic::Policy subclass module. The
'Perl::Critic::Policy' portion of the name can be omitted for
brevity. This argument is required.
-params is an optional reference to a hash of Policy parameters. The
contents of this hash reference will be passed into to the
constructor of the Policy module. See the documentation in the
relevant Policy module for a description of the arguments it
supports.
" policies() "
Returns a list containing references to all the Policy objects that
have been loaded into this engine. Objects will be in the order that
they were loaded.
" config() "
Returns the Perl::Critic::Config object that was created for or
given to this Critic.
" statistics() "
Returns the Perl::Critic::Statistics object that was created for
this Critic. The Statistics object accumulates data for all files
that are analyzed by this Critic.
FUNCTIONAL INTERFACE
For those folks who prefer to have a functional interface, The
"critique" method can be exported on request and called as a static
function. If the first argument is a hashref, its contents are used to
construct a new Perl::Critic object internally. The keys of that hash
should be the same as those supported by the "Perl::Critic::new" method.
Here are some examples:
use Perl::Critic qw(critique);
# Use default parameters...
@violations = critique( $some_file );
# Use custom parameters...
@violations = critique( {-severity => 2}, $some_file );
# As a one-liner
%> perl -MPerl::Critic=critique -e 'print critique(shift)' some_file.pm
None of the other object-methods are currently supported as static
functions. Sorry.
CONFIGURATION
Most of the settings for Perl::Critic and each of the Policy modules can
be controlled by a configuration file. The default configuration file is
called .perlcriticrc. Perl::Critic will look for this file in the
current directory first, and then in your home directory. Alternatively,
you can set the "PERLCRITIC" environment variable to explicitly point to
a different file in another location. If none of these files exist, and
the "-profile" option is not given to the constructor, then all the
modules that are found in the Perl::Critic::Policy namespace will be
loaded with their default configuration.
The format of the configuration file is a series of INI-style blocks
that contain key-value pairs separated by '='. Comments should start
with '#' and can be placed on a separate line or after the name-value
pairs if you desire.
Default settings for Perl::Critic itself can be set before the first
named block. For example, putting any or all of these at the top of your
configuration file will set the default value for the corresponding
constructor argument.
severity = 3 #Integer or named level
only = 1 #Zero or One
force = 0 #Zero or One
verbose = 4 #Integer or format spec
top = 50 #A positive integer
theme = (pbp || security) && bugs #A theme expression
include = NamingConventions ClassHierarchies #Space-delimited list
exclude = Variables Modules::RequirePackage #Space-delimited list
criticism-fatal = 1 #Zero or One
color = 1 #Zero or One
allow-unsafe = 1 #Zero or One
pager = less #pager to pipe output to
The remainder of the configuration file is a series of blocks like this:
[Perl::Critic::Policy::Category::PolicyName]
severity = 1
set_themes = foo bar
add_themes = baz
maximum_violations_per_document = 57
arg1 = value1
arg2 = value2
"Perl::Critic::Policy::Category::PolicyName" is the full name of a
module that implements the policy. The Policy modules distributed with
Perl::Critic have been grouped into categories according to the table of
contents in Damian Conway's book Perl Best Practices. For brevity, you
can omit the 'Perl::Critic::Policy' part of the module name.
"severity" is the level of importance you wish to assign to the Policy.
All Policy modules are defined with a default severity value ranging
from 1 (least severe) to 5 (most severe). However, you may disagree with
the default severity and choose to give it a higher or lower severity,
based on your own coding philosophy. You can set the "severity" to an
integer from 1 to 5, or use one of the equivalent names:
SEVERITY NAME ...is equivalent to... SEVERITY NUMBER
----------------------------------------------------
gentle 5
stern 4
harsh 3
cruel 2
brutal 1
The names reflect how severely the code is criticized: a "gentle"
criticism reports only the most severe violations, and so on down to a
"brutal" criticism which reports even the most minor violations.
"set_themes" sets the theme for the Policy and overrides its default
theme. The argument is a string of one or more whitespace-delimited
alphanumeric words. Themes are case-insensitive. See "POLICY THEMES" for
more information.
"add_themes" appends to the default themes for this Policy. The argument
is a string of one or more whitespace-delimited words. Themes are
case-insensitive. See "POLICY THEMES" for more information.
"maximum_violations_per_document" limits the number of Violations the
Policy will return for a given document. Some Policies have a default
limit; see the documentation for the individual Policies to see whether
there is one. To force a Policy to not have a limit, specify "no_limit"
or the empty string for the value of this parameter.
The remaining key-value pairs are configuration parameters that will be
passed into the constructor for that Policy. The constructors for most
Policy objects do not support arguments, and those that do should have
reasonable defaults. See the documentation on the appropriate Policy
module for more details.
Instead of redefining the severity for a given Policy, you can
completely disable a Policy by prepending a '-' to the name of the
module in your configuration file. In this manner, the Policy will never
be loaded, regardless of the "-severity" given to the Perl::Critic
constructor.
A simple configuration might look like this:
#--------------------------------------------------------------
# I think these are really important, so always load them
[TestingAndDebugging::RequireUseStrict]
severity = 5
[TestingAndDebugging::RequireUseWarnings]
severity = 5
#--------------------------------------------------------------
# I think these are less important, so only load when asked
[Variables::ProhibitPackageVars]
severity = 2
[ControlStructures::ProhibitPostfixControls]
allow = if unless # My custom configuration
severity = cruel # Same as "severity = 2"
#--------------------------------------------------------------
# Give these policies a custom theme. I can activate just
# these policies by saying `perlcritic -theme larry`
[Modules::RequireFilenameMatchesPackage]
add_themes = larry
[TestingAndDebugging::RequireTestLables]
add_themes = larry curly moe
#--------------------------------------------------------------
# I do not agree with these at all, so never load them
[-NamingConventions::Capitalization]
[-ValuesAndExpressions::ProhibitMagicNumbers]
#--------------------------------------------------------------
# For all other Policies, I accept the default severity,
# so no additional configuration is required for them.
For additional configuration examples, see the perlcriticrc file that is
included in this examples directory of this distribution.
Damian Conway's own Perl::Critic configuration is also included in this
distribution as examples/perlcriticrc-conway.
THE POLICIES
A large number of Policy modules are distributed with Perl::Critic. They
are described briefly in the companion document
Perl::Critic::PolicySummary and in more detail in the individual modules
themselves. Say ""perlcritic -doc PATTERN"" to see the perldoc for all
Policy modules that match the regex "m/PATTERN/ixms"
There are a number of distributions of additional policies on CPAN. If
Perl::Critic doesn't contain a policy that you want, some one may have
already written it. See the "SEE ALSO" section below for a list of some
of these distributions.
POLICY THEMES
Each Policy is defined with one or more "themes". Themes can be used to
create arbitrary groups of Policies. They are intended to provide an
alternative mechanism for selecting your preferred set of Policies. For
example, you may wish disable a certain subset of Policies when
analyzing test programs. Conversely, you may wish to enable only a
specific subset of Policies when analyzing modules.
The Policies that ship with Perl::Critic have been broken into the
following themes. This is just our attempt to provide some basic logical
groupings. You are free to invent new themes that suit your needs.
THEME DESCRIPTION
--------------------------------------------------------------------------
core All policies that ship with Perl::Critic
pbp Policies that come directly from "Perl Best Practices"
bugs Policies that that prevent or reveal bugs
maintenance Policies that affect the long-term health of the code
cosmetic Policies that only have a superficial effect
complexity Policies that specificaly relate to code complexity
security Policies that relate to security issues
tests Policies that are specific to test programs
Any Policy may fit into multiple themes. Say "perlcritic -list" to get a
listing of all available Policies and the themes that are associated
with each one. You can also change the theme for any Policy in your
.perlcriticrc file. See the "CONFIGURATION" section for more information
about that.
Using the "-theme" option, you can create an arbitrarily complex rule
that determines which Policies will be loaded. Precedence is the same as
regular Perl code, and you can use parentheses to enforce precedence as
well. Supported operators are:
Operator Altertative Example
-----------------------------------------------------------------
&& and 'pbp && core'
|| or 'pbp || (bugs && security)'
! not 'pbp && ! (portability || complexity)'
Theme names are case-insensitive. If the "-theme" is set to an empty
string, then it evaluates as true all Policies.
BENDING THE RULES
Perl::Critic takes a hard-line approach to your code: either you comply
or you don't. In the real world, it is not always practical (nor even
possible) to fully comply with coding standards. In such cases, it is
wise to show that you are knowingly violating the standards and that you
have a Damn Good Reason (DGR) for doing so.
To help with those situations, you can direct Perl::Critic to ignore
certain lines or blocks of code by using annotations:
require 'LegacyLibaray1.pl'; ## no critic
require 'LegacyLibrary2.pl'; ## no critic
for my $element (@list) {
## no critic
$foo = ""; #Violates 'ProhibitEmptyQuotes'
$barf = bar() if $foo; #Violates 'ProhibitPostfixControls'
#Some more evil code...
## use critic
#Some good code...
do_something($_);
}
The "## no critic" annotations direct Perl::Critic to ignore the
remaining lines of code until a "## use critic" annotation is found. If
the ""## no critic"" annotation is on the same line as a code statement,
then only that line of code is overlooked. To direct perlcritic to
ignore the ""## no critic"" annotations, use the "--force" option.
A bare "## no critic" annotation disables all the active Policies. If
you wish to disable only specific Policies, add a list of Policy names
as arguments, just as you would for the "no strict" or ""no warnings""
pragmas. For example, this would disable the "ProhibitEmptyQuotes" and
"ProhibitPostfixControls" policies until the end of the block or until
the next "## use critic" annotation (whichever comes first):
## no critic (EmptyQuotes, PostfixControls)
# Now exempt from ValuesAndExpressions::ProhibitEmptyQuotes
$foo = "";
# Now exempt ControlStructures::ProhibitPostfixControls
$barf = bar() if $foo;
# Still subjected to ValuesAndExpression::RequireNumberSeparators
$long_int = 10000000000;
Since the Policy names are matched against the "## no critic" arguments
as regular expressions, you can abbreviate the Policy names or disable
an entire family of Policies in one shot like this:
## no critic (NamingConventions)
# Now exempt from NamingConventions::Capitalization
my $camelHumpVar = 'foo';
# Now exempt from NamingConventions::Capitalization
sub camelHumpSub {}
The argument list must be enclosed in parentheses and must contain one
or more comma-separated barewords (e.g. don't use quotes). The "## no
critic" annotations can be nested, and Policies named by an inner
annotation will be disabled along with those already disabled an outer
annotation.
Some Policies like "Subroutines::ProhibitExcessComplexity" apply to an
entire block of code. In those cases, "## no critic" must appear on the
line where the violation is reported. For example:
sub complicated_function { ## no critic (ProhibitExcessComplexity)
# Your code here...
}
Policies such as "Documentation::RequirePodSections" apply to the entire
document, in which case violations are reported at line 1.
Use this feature wisely. "## no critic" annotations should be used in
the smallest possible scope, or only on individual lines of code. And
you should always be as specific as possible about which Policies you
want to disable (i.e. never use a bare "## no critic"). If Perl::Critic
complains about your code, try and find a compliant solution before
resorting to this feature.
THE Perl::Critic PHILOSOPHY
Coding standards are deeply personal and highly subjective. The goal of
Perl::Critic is to help you write code that conforms with a set of best
practices. Our primary goal is not to dictate what those practices are,
but rather, to implement the practices discovered by others. Ultimately,
you make the rules -- Perl::Critic is merely a tool for encouraging
consistency. If there is a policy that you think is important or that we
have overlooked, we would be very grateful for contributions, or you can
simply load your own private set of policies into Perl::Critic.
EXTENDING THE CRITIC
The modular design of Perl::Critic is intended to facilitate the
addition of new Policies. You'll need to have some understanding of PPI,
but most Policy modules are pretty straightforward and only require
about 20 lines of code. Please see the Perl::Critic::DEVELOPER file
included in this distribution for a step-by-step demonstration of how to
create new Policy modules.
If you develop any new Policy modules, feel free to send them to
"<jeff@imaginative-software.com>" and I'll be happy to put them into the
Perl::Critic distribution. Or if you would like to work on the
Perl::Critic project directly, check out our repository at
<http://perlcritic.tigris.org>. To subscribe to our mailing list, send a
message to <mailto:dev-subscribe@perlcritic.tigris.org>.
The Perl::Critic team is also available for hire. If your organization
has its own coding standards, we can create custom Policies to enforce
your local guidelines. Or if your code base is prone to a particular
defect pattern, we can design Policies that will help you catch those
costly defects before they go into production. To discuss your needs
with the Perl::Critic team, just contact
"<jeff@imaginative-software.com>".
PREREQUISITES
Perl::Critic requires the following modules:
B::Keywords
Config::Tiny
Email::Address
Exception::Class
File::Spec
File::Spec::Unix
IO::String
List::MoreUtils
List::Util
Module::Pluggable
Perl::Tidy
Pod::Spell
PPI
Pod::PlainText
Pod::Select
Pod::Usage
Readonly
Scalar::Util
String::Format
Task::Weaken
Text::ParseWords
version
The following modules are optional, but recommended for complete
functionality:
File::HomeDir
File::Which
CONTACTING THE DEVELOPMENT TEAM
You are encouraged to subscribe to the mailing list; send a message to
<mailto:users-subscribe@perlcritic.tigris.org>. See also the archives at
<http://perlcritic.tigris.org/servlets/SummarizeList?listName=users>.
You can also contact the author at "<jeff@imaginative-software.com>".
At least one member of the development team has started hanging around
in <irc://irc.perl.org/#perlcritic>.
You can also follow Perl::Critic on Twitter, at
<https://twitter.com/perlcritic>.
SEE ALSO
There are a number of distributions of additional Policies available. A
few are listed here:
Perl::Critic::More
Perl::Critic::Bangs
Perl::Critic::Lax
Perl::Critic::StricterSubs
Perl::Critic::Swift
Perl::Critic::Tics
These distributions enable you to use Perl::Critic in your unit tests:
Test::Perl::Critic
Test::Perl::Critic::Progressive
There is also a distribution that will install all the Perl::Critic
related modules known to the development team:
Task::Perl::Critic
If you want to make sure you have absolutely everything, you can use
this:
Task::Perl::Critic::IncludingOptionalDependencies
BUGS
Scrutinizing Perl code is hard for humans, let alone machines. If you
find any bugs, particularly false-positives or false-negatives from a
Perl::Critic::Policy, please submit them to
<http://rt.cpan.org/NoAuth/Bugs.html?Dist=Perl-Critic>. Thanks.
Most policies will produce false-negatives if they cannot understand a
particular block of code.
CREDITS
Adam Kennedy - For creating PPI, the heart and soul of Perl::Critic.
Damian Conway - For writing Perl Best Practices, finally :)
Chris Dolan - For contributing the best features and Policy modules.
Andy Lester - Wise sage and master of all-things-testing.
Elliot Shank - The self-proclaimed quality freak.
Giuseppe Maxia - For all the great ideas and positive encouragement.
and Sharon, my wife - For putting up with my all-night code sessions.
Thanks also to the Perl Foundation for providing a grant to support
Chris Dolan's project to implement twenty PBP policies.
<http://www.perlfoundation.org/april_1_2007_new_grant_awards>
AUTHOR
Jeffrey Ryan Thalhammer <jeff@imaginative-software.com>
COPYRIGHT
Copyright (c) 2005-2011 Imaginative Software Systems. All rights
reserved.
This program is free software; you can redistribute it and/or modify it
under the same terms as Perl itself. The full text of this license can
be found in the LICENSE file included with this module.