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Perl-Critic-0.12
River stage three • 131 direct dependents • 408 total dependents
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/ perlcritic

NAME

perlcritic - Command-line interface to critique Perl souce

SYNOPSIS

 perlcritic [options] FILE  #Read from FILE
 perlcritic [options]       #Read from STDIN

DESCRIPTION

perlcritic is a Perl source code analyzer. It is the executable front-end to the Perl::Critic engine, which attempts to enforce the coding standards outlined in Damian Conway's book Perl Best Practices. I highly recommend that you get a copy!

If you want to integrate perlcritic with your build process, Test::Perl::Critic provides a nice interface that is suitable for test scripts.

ARGUMENTS

The only argument is the path to the file you wish to analyze. No more than one file can be specified at a time. If the file is not specified, then the input is read from STDIN.

OPTIONS

Option names can be abbreviated to uniqueness, and can be stated with singe or double dashes, and option values can be separated from the option name by a space or '=' (a la Getopt::Long).

-priority N

Sets the the maximum priority value of Policies that should be loaded. 1 is the "highest" priority, and all numbers larger than 1 have "lower" priority. Only Policies that have been configured with a priority value less than or equal to N will be loaded. For a given -profile, increasing N will result in more violations. The default priority is 1. See "CONFIGURATION" for more information.

-profile FILE

Directs perlcritic to use a profile named by FILE rather than looking for the default .perlcriticrc file in the current directory or your home directory. See "CONFIGURATION" for more information.

-noprofile

Directs perlcritic not to load any configuration file, thus defaulting to load all the Policy modules that are distributed with Perl::Critic.

-force

Directs perlcritic not to observe the magical ## no critic pseudo-pragmas in the source code. See "BENDING THE RULES" for more information.

-verbose N | FORMAT

Sets the verbosity level or format for reporting violations. If given a number, perlcritic reports violations using one of the pre-defined formats outlined below. If given a string, it is interpreted to be an actual format specification.

  Verbosity     Format Specification
  -----------   ----------------------------------------------------
  1             "%f:%l:%c:%m."
  2 (default)   "%m at line %l, column %c. %e."
  3             "[%p] %m at line %1, column %c. %e."
  4             "[%p] %m at line %1, column %c. %e. %d"

Formats are a combination of literal and escape characters similar to the way sprintf works. Do not put any metacharacters (like "\n") in your format. Valid escape characters are:

  Escape    Meaning
  -------   -------------------------------------------------------
  %m        Brief description of the violation
  %f        Name of the file where the violation ocurred.
  %l        Line number where the violation occured
  %c        Column number where the violation occured
  %e        Explanation of violation or page numbers in PBP
  %d        Full diagnostic discussion of the violation
  %p        Name of the Policy module that created the violation

The purpose of these formats is to provide some compatibility with editors that have an qinterface for parsing certain kinds of input. See "EDITOR INGEGRATION" for more information about that.

-safari

Report "Perl Best Practice" citations as section numbers from http://safari.oreilly.com instead of page numbers from the actual book. NOTE: This feature is not implemented yet.

-help
-?

Displays a brief summary of options and exits.

-man

Displays the complete perlcritic manual and exits.

-version

Displays the version number of perlcritic and exits.

CONFIGURATION

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 configuration file in another location. If none of these files exist, And the -profile option is not given at the command-line, perlcritic defaults to loading all the Policies that are distributed with Perl::Critic.

The format of the configuration file is a series of named sections 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. The general recipe is a series of blocks like this:

    [Perl::Critic::Policy::Category::PolicyName]
    priority = 1
    arg1 = value1
    arg2 = value2

Perl::Critic::Policy::Category::PolicyName is the full name of a module that implements the policy you want to load into the engine. 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 ommit the 'Perl::Critic::Policy' part of the module name. The module must be a subclass of Perl::Critic::Policy.

priority is the level of importance you wish to assign to this policy. 1 is the "highest" priority level, and all numbers greater than 1 have increasingly "lower" priority. Only those policies with a priority less than or equal to the -priority value given on the command-line will be loaded. The priority can be an arbitrarily large positive integer. If the priority is not defined, it defaults to 1.

The remaining key-value pairs are configuration parameters for that specific Policy and will be passed into the constructor of the Perl::Critic::Policy subclass. The constructors for most Policy modules do not support arguments, and those that do should have reasonable defaults. See the documentation in the relevant Policy module for more details.

By default, all the policies that are distributed with Perl::Critic are loaded. Rather than assign a priority level to a Policy, you can simply "turn off" a Policy by prepending a '-' to the name of the module in the config file. In this manner, the Policy will never be loaded, regardless of the -priority option given at the command-line.

A sample configuration might look like this:

    #--------------------------------------------------------------
    # These are really important, so always load them

    [TestingAndDebugging::RequirePackageStricture]
    priority = 1

    [TestingAndDebugging::RequirePackageWarnings]
    priority = 1

    #--------------------------------------------------------------
    # These are less important, so only load when asked

    [Variables::ProhibitPackageVars]
    priority = 2

    [ControlStructures::ProhibitPostfixControls]
    priority = 2

    #--------------------------------------------------------------
    # I don't agree with these, so never load them

    [-NamingConventions::ProhibitMixedCaseVars]
    [-NamingConventions::ProhibitMixedCaseSubs]

THE POLICIES

The following Policy modules are distributed with Perl::Critic. The Policy modules have been categorized according to the table of contents in Damian Conway's book Perl Best Practices. Since most coding standards take the form "do this..." or "don't do that...", I have adopted the convention of naming each module RequireSomething or ProhibitSomething. See the documentation of each module for it's specific details.

Perl::Critic::Policy::BuiltinFunctions::ProhibitStringyEval

Write eval { my $foo; bar($foo) } instead of eval "my $foo; bar($foo);"

Perl::Critic::Policy::BuiltinFunctions::RequireBlockGrep

Write grep { $_ =~ /$pattern/ } @list instead of grep /$pattern/, @list

Perl::Critic::Policy::BuiltinFunctions::RequireBlockMap

Write map { $_ =~ /$pattern/ } @list instead of map /$pattern/, @list

Perl::Critic::Policy::BuiltinFunctions::RequireGlobFunction

Use glob q{*} instead of <*>

Perl::Critic::Policy::CodeLayout::ProhibitHardTabs

Use spaces instead of tabs

Perl::Critic::Policy::CodeLayout::ProhibitParensWithBuiltins

Write open $handle, $path instead of open($handle, $path)

Perl::Critic::Policy::CodeLayout::RequireTidyCode

Must run code through perltidy

Perl::Critic::Policy::ControlStructures::ProhibitCascadingIfElse

Don't write long "if-elsif-elsif-elsif-elsif...else" chains

Perl::Critic::Policy::ControlStructures::ProhibitCStyleForLoops

Write for(0..20) instead of for($i=0; $i<=20; $i++)

Perl::Critic::Policy::ControlStructures::ProhibitPostfixControls

Write if($condition){ do_something() } instead of do_something() if $condition

Perl::Critic::Policy::ControlStructures::ProhibitUnlessBlocks

Write if(! $condition) instead of unless($condition)

Perl::Critic::Policy::ControlStructures::ProhibitUntilBlocks

Write while(! $condition) instead of until($condition)

Perl::Critic::Policy::InputOutput::ProhibitBacktickOperators

Discourage stuff like @files = `ls $directory`

Perl::Critic::Policy::Modules::ProhibitMultiplePackages

Put packages (especially subclasses) in separate files

Perl::Critic::Policy::Modules::ProhibitRequireStatements

Write use Module instead of require 'Module.pm'

Perl::Critic::Policy::Modules::ProhibitSpecificModules

Don't use evil modules

Perl::Critic::Policy::Modules::ProhibitUnpackagedCode

Always make the package explicit

Perl::Critic::Policy::NamingConventions::ProhibitMixedCaseSubs

Write sub my_function{} instead of sub MyFunction{}

Perl::Critic::Policy::NamingConventions::ProhibitMixedCaseVars

Write $my_variable = 42 instead of $MyVariable = 42

Perl::Critic::Policy::Subroutines::ProhibitBuiltinHomonyms

Don't declare your own open function.

Perl::Critic::Policy::Subroutines::ProhibitExplicitReturnUndef

Return failure with bare return instead of return undef

Perl::Critic::Policy::Subroutines::ProhibitSubroutinePrototypes

Don't write sub my_function (@@) {}

Perl::Critic::Policy::TestingAndDebugging::RequirePackageStricture

Always use strict

Perl::Critic::Policy::TestingAndDebugging::RequirePackageWarnings

Always use warnings

Perl::Critic::Policy::ValuesAndExpressions::ProhibitConstantPragma

Don't use constant $FOO = 15>

Perl::Critic::Policy::ValuesAndExpressions::ProhibitEmptyQuotes

Write q{} instead of ''

Perl::Critic::Policy::ValuesAndExpressions::ProhibitInterpolationOfLiterals

Always use single quotes for literal strings.

Perl::Critic::Policy::ValuesAndExpressions::ProhibitLeadingZeros

Write oct(755) instead of 0755

Perl::Critic::Policy::ValuesAndExpressions::ProhibitNoisyQuotes

Use q{} or qq{} instead of quotes for awkward-looking strings

Perl::Critic::Policy::ValuesAndExpressions::RequireInterpolationOfMetachars

Warns that you might have used single quotes when you really wanted double-quotes.

Perl::Critic::Policy::ValuesAndExpressions::RequireNumberSeparators

Write 141_234_397.0145 instead of 141234397.0145

Perl::Critic::Policy::ValuesAndExpressions::RequireQuotedHeredocTerminator

Write print <<'THE_END' or print <<"THE_END"

Perl::Critic::Policy::ValuesAndExpressions::RequireUpperCaseHeredocTerminator

Perl::Critic::Policy::Variables::ProhibitLocalVars

Use my instead of local, except when you have to.

Perl::Critic::Policy::Variables::ProhibitPackageVars

Eliminate globals declared with our or use vars

Perl::Critic::Policy::Variables::ProhibitPunctuationVars

Write $EVAL_ERROR instead of $@

BENDING THE RULES

NOTE: This feature changed in version 0.09 and is not backward compatible with earlier versions.

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 (or even possible) to fully comply with coding standards. In such cases, it is wise to show that you are knowlingly 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 pseudo-pragmas:

    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" comments direct Perl::Critic to overlook the remaining lines of code until the end of the current block, or until a "## use critic" comment is found (whichever comes first). If the "## no critic" comment 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" comments, use the -force option.

Use this feature wisely. "## no critic" should be used in the smallest possible scope, or only on individual lines of code. If Perl::Critic complains about your code, try and find a compliant solution before resorting to this feature.

EDITOR INTEGRATION

For ease-of-use, perlcritic can be integrated with your favorite text editor. The output-formatting capabilities of perlcritic are specifically intended for use with the "grep" or "compile" modes available in editors like emacs and vim. In these modes, you can run an arbitrary command and the editor will parse the output into an interactive buffer that you can click on and jump to the relevant line of code.

EMACS

Entering 'Meta-x compile' causes emacs to switch to compile-mode. Next, enter the following command in the minibuffer:

  perlcritic -verbose 1 path/to/your/file

When the results are displayed, pressing [Enter] on any of the Violation messages will move the pointer to the relevant location within the file. Type 'Ctrl-h a compile' for information about compile-mode.

VIM

Configure the grep format as follows:

  set grepformat=%f:%l:%c:m
  set grepprg=perlcritic\ -verbose\ 1\ %

Then, you can run perlcritic on the current buffer with:

  :grep

Navigation and display instructions can be found under :help grep. Someone with stronger Vim-fu may wish to convert this to a real macro.

EXIT STATUS

If perlcritic has any errors itself, exits with status == 1. If there are no errors, but perlcritic finds Policy violations in your source code, exits with status == 2. If there were no errors and no violations were found, exits with status == 0.

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.

CREDITS

Adam Kennedy - For creating PPI, the heart and soul of Perl::Critic.

Damian Conway - For writing Perl Best Practices

Giuseppe Maxia - For all the great ideas and enhancements.

Sharon, my wife - For putting up with my all-night code sessions

AUTHOR

Jeffrey Ryan Thalhammer <thaljef@cpan.org>

COPYRIGHT

Copyright (c) 2005 Jeffrey Ryan Thalhammer. 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.