B::Lint - Perl lint - metacpan.org

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class="ellipsis">Module::Pluggable</a></li> <li><a href="/pod/if" title="if" class="ellipsis">if</a></li> <li><i class="ttip" title="dynamic_config enabled">and possibly others</i></li> <li> <hr> </li> <li> <a href="/module/B::Lint/requires">Reverse dependencies</a> </li> <li> <a href="http://deps.cpantesters.org/?module=B%3A%3ALint">CPAN Testers List</a> </li> <li> <a href="https://cpandeps.grinnz.com/?dist=B-Lint">Dependency graph</a> </li> </ul> </li> <li class="nav-header">Permalinks</li> <li> <a href="/release/RJBS/B-Lint-1.20/view/lib/B/Lint.pm">This version</a> </li> <li> <a href="/pod/B::Lint">Latest version</a> </li> <li> <div class="plussers"> <div class="nav-header">++ed by:</div> <div> <a class="display-all" href="/author/AYOUNG"><img src="https://www.gravatar.com/avatar/8d1e4946c288fbe87d1e0394f3e41b24?d=identicon&s=20" title="AYOUNG" alt="AYOUNG"></a> <a class="display-all" href="/author/RSCHABER"><img src="https://www.gravatar.com/avatar/8735b8d5583ee0a0155a41f993cab4f3?d=identicon&s=20" title="RSCHABER" alt="RSCHABER"></a> <a class="display-all" href="/author/BIFFEN"><img src="https://www.gravatar.com/avatar/ceeeed15488c70dd4fd2597cec3d0035?d=identicon&s=20" title="BIFFEN" alt="BIFFEN"></a> </div>  <div> <a href="/dist/B-Lint/plussers">3 PAUSE users</a> </div> <div> 3 non-PAUSE users </div> </div> </li> <li> <div> <button class="contributors-show-button btn-link">and 1 contributors</button> <div id="metacpan_contributors" class="slide-out slide-out-hidden"> <div> <ul> <li class="contributor" data-cpan-author="JJORE" data-contrib-email="jjore@cpan.org" > <a href="/author/JJORE" class="cpan-author"> <img class="gravatar" width="20" height="20" src="https://www.gravatar.com/avatar/3241e95bc2abb9c6a0853b51fff3da9f?d=identicon&s=20" /> Joshua ben Jore </a> </li> </ul> </div> </div> </div> </li> </ul> </div> </nav> <div class="content-navigation"> <div class="breadcrumbs"> <span> <a data-keyboard-shortcut="g a" rel="author" href="/author/RJBS" class="author-name">Ricardo SIGNES 🙂</a> </span> <span> / </span> <div class="release dist-release status-latest maturity-released"> <span class="dropdown"><b class="caret"></b></span> <select class="select-navigator "> <option value="/release/RURBAN/B-Lint-1.22/view/lib/B/Lint.pm" >1.22 (RURBAN on 2017-11-13)</option> <option value="/release/RURBAN/B-Lint-1.21/view/lib/B/Lint.pm" >1.21 (RURBAN on 2017-11-13)</option> <option value="/release/RURBAN/B-Lint-1.20/view/lib/B/Lint.pm" >1.20 (RURBAN on 2017-11-13)</option> <option selected value="/release/RJBS/B-Lint-1.20/view/lib/B/Lint.pm" >1.20 (RJBS on 2014-10-26)</option> <option value="/release/RJBS/B-Lint-1.19/view/lib/B/Lint.pm" >1.19 (RJBS on 2014-10-23)</option> <option value="/release/FLORA/B-Lint-1.14/view/lib/B/Lint.pm" >1.14 (FLORA on 2012-09-11)</option> <option value="/release/FLORA/B-Lint-1.13/view/lib/B/Lint.pm" >1.13 (FLORA on 2011-07-09)</option> <option value="/release/FLORA/B-Lint-1.12/view/lib/B/Lint.pm" >1.12 (FLORA on 2010-07-24)</option> <option value="/release/JJORE/B-Lint-1.11/view/lib/B/Lint.pm" >1.11 (JJORE on 2007-10-08)</option> <optgroup label="BackPAN">' <option value="/release/RJBS/B-Lint-1.18/view/lib/B/Lint.pm" >1.18 (RJBS on 2014-09-29)</option> <option value="/release/RJBS/B-Lint-1.17/view/lib/B/Lint.pm" >1.17 (RJBS on 2013-01-26)</option> <option value="/release/RJBS/B-Lint-1.16/view/lib/B/Lint.pm" >1.16 (RJBS on 2013-01-25)</option> <option value="/release/RJBS/B-Lint-1.15/view/lib/B/Lint.pm" >1.15 (RJBS on 2013-01-25)</option> <option value="/release/JJORE/B-Lint-1.10/view/lib/B/Lint.pm" >1.10 (JJORE on 2007-10-08)</option> <option value="/release/JJORE/B-Lint-1.09/view/lib/B/Lint.pm" >1.09 (JJORE on 2007-03-19)</option> </optgroup> </select> <a data-keyboard-shortcut="g d" class="release-name" href="/dist/B-Lint">B-Lint-1.20</a> </div> <span class="river-gauge-gauge"> <svg width="24px" height="15px" version="1.1" xmlns="http://www.w3.org/2000/svg" xmlns:xlink="http://www.w3.org/1999/xlink"> <g> <title> River stage one 
 • 2 direct dependents 
 • 2 total dependents </title> <rect x="0" y="0" width="4" height="15" fill="#7ea3f2" /> <rect x="5" y="0" width="4" height="15" fill="#e4e2e2" /> <rect x="10" y="0" width="4" height="15" fill="#e4e2e2" /> <rect x="15" y="0" width="4" height="15" fill="#e4e2e2" /> <rect x="20" y="0" width="4" height="15" fill="#e4e2e2" /> </g> </svg> </span> <div id="B-Lint-fav" class="show-logged-in"> <form action="/account/favorite/add" style="display: inline" method="POST"> <input type="hidden" name="remove" value="0"> <input type="hidden" name="release" value="B-Lint-1.20"> <input type="hidden" name="author" value="RJBS"> <input type="hidden" name="distribution" value="B-Lint"> <button type="submit" class="favorite highlight"><span>6</span> ++</button> </form> </div> <div class="show-logged-out"> <button class="fav-not-logged-in favorite highlight"><span>6</span> ++</button> </div> / <span>B::Lint</span> </div> </div> <main class="content"> <nav class="toc"> <div class="toc-header"><strong>Contents</strong></div> <ul> <li><a href="#NAME">NAME</a></li> <li><a href="#SYNOPSIS">SYNOPSIS</a></li> <li><a href="#DESCRIPTION">DESCRIPTION</a></li> <li><a href="#OPTIONS-AND-LINT-CHECKS">OPTIONS AND LINT CHECKS</a></li> <li><a href="#NON-LINT-CHECK-OPTIONS">NON LINT-CHECK OPTIONS</a></li> <li><a href="#EXTENDING-LINT">EXTENDING LINT</a></li> <li><a href="#TODO">TODO</a></li> <li><a href="#BUGS">BUGS</a></li> <li><a href="#AUTHOR">AUTHOR</a></li> <li><a href="#ACKNOWLEDGEMENTS">ACKNOWLEDGEMENTS</a></li> </ul></nav> <div class="pod anchors"> <h1 id="NAME">NAME</h1> <p>B::Lint - Perl lint</p> <h1 id="SYNOPSIS">SYNOPSIS</h1> <p>perl -MO=Lint[,OPTIONS] foo.pl</p> <h1 id="DESCRIPTION">DESCRIPTION</h1> <p>The B::Lint module is equivalent to an extended version of the <b>-w</b> option of <b>perl</b>. It is named after the program <i>lint</i> which carries out a similar process for C programs.</p> <h1 id="OPTIONS-AND-LINT-CHECKS"><a id="OPTIONS"></a>OPTIONS AND LINT CHECKS</h1> <p>Option words are separated by commas (not whitespace) and follow the usual conventions of compiler backend options. Following any options (indicated by a leading <b>-</b>) come lint check arguments. Each such argument (apart from the special <b>all</b> and <b>none</b> options) is a word representing one possible lint check (turning on that check) or is <b>no-foo</b> (turning off that check). Before processing the check arguments, a standard list of checks is turned on. Later options override earlier ones. Available options are:</p> <dl> <dt id="magic-diamond"><a id="magic"></a><b>magic-diamond</b></dt> <dd> <p>Produces a warning whenever the magic <code><></code> readline is used. Internally it uses perl's two-argument open which itself treats filenames with special characters specially. This could allow interestingly named files to have unexpected effects when reading.</p> <pre><code>% touch 'rm *|' % perl -pe 1</code></pre> <p>The above creates a file named <code>rm *|</code>. When perl opens it with <code><></code> it actually executes the shell program <code>rm *</code>. This makes <code><></code> dangerous to use carelessly.</p> </dd> <dt id="context"><b>context</b></dt> <dd> <p>Produces a warning whenever an array is used in an implicit scalar context. For example, both of the lines</p> <pre><code>$foo = length(@bar); $foo = @bar;</code></pre> <p>will elicit a warning. Using an explicit <b>scalar()</b> silences the warning. For example,</p> <pre><code>$foo = scalar(@bar);</code></pre> </dd> <dt id="implicit-read-and-implicit-write"><a id="implicit"></a><b>implicit-read</b> and <b>implicit-write</b></dt> <dd> <p>These options produce a warning whenever an operation implicitly reads or (respectively) writes to one of Perl's special variables. For example, <b>implicit-read</b> will warn about these:</p> <pre><code>/foo/;</code></pre> <p>and <b>implicit-write</b> will warn about these:</p> <pre><code>s/foo/bar/;</code></pre> <p>Both <b>implicit-read</b> and <b>implicit-write</b> warn about this:</p> <pre><code>for (@a) { ... }</code></pre> </dd> <dt id="bare-subs"><a id="bare"></a><b>bare-subs</b></dt> <dd> <p>This option warns whenever a bareword is implicitly quoted, but is also the name of a subroutine in the current package. Typical mistakes that it will trap are:</p> <pre><code>use constant foo => 'bar'; @a = ( foo => 1 ); $b{foo} = 2;</code></pre> <p>Neither of these will do what a naive user would expect.</p> </dd> <dt id="dollar-underscore"><a id="dollar"></a><b>dollar-underscore</b></dt> <dd> <p>This option warns whenever <code>$_</code> is used either explicitly anywhere or as the implicit argument of a <b>print</b> statement.</p> </dd> <dt id="private-names"><a id="private"></a><b>private-names</b></dt> <dd> <p>This option warns on each use of any variable, subroutine or method name that lives in a non-current package but begins with an underscore ("_"). Warnings aren't issued for the special case of the single character name "_" by itself (e.g. <code>$_</code> and <code>@_</code>).</p> </dd> <dt id="undefined-subs"><a id="undefined"></a><b>undefined-subs</b></dt> <dd> <p>This option warns whenever an undefined subroutine is invoked. This option will only catch explicitly invoked subroutines such as <code>foo()</code> and not indirect invocations such as <code>&$subref()</code> or <code>$obj->meth()</code>. Note that some programs or modules delay definition of subs until runtime by means of the AUTOLOAD mechanism.</p> </dd> <dt id="regexp-variables"><a id="regexp"></a><b>regexp-variables</b></dt> <dd> <p>This option warns whenever one of the regexp variables <code>$`</code>, <code>$&</code> or <code>$'</code> is used. Any occurrence of any of these variables in your program can slow your whole program down. See <a href="/pod/perlre">perlre</a> for details.</p> </dd> <dt id="all"><b>all</b></dt> <dd> <p>Turn all warnings on.</p> </dd> <dt id="none"><b>none</b></dt> <dd> <p>Turn all warnings off.</p> </dd> </dl> <h1 id="NON-LINT-CHECK-OPTIONS"><a id="NON"></a>NON LINT-CHECK OPTIONS</h1> <dl> <dt id="-u-Package"><a id="u-Package"></a><b>-u Package</b></dt> <dd> <p>Normally, Lint only checks the main code of the program together with all subs defined in package main. The <b>-u</b> option lets you include other package names whose subs are then checked by Lint.</p> </dd> </dl> <h1 id="EXTENDING-LINT"><a id="EXTENDING"></a>EXTENDING LINT</h1> <p>Lint can be extended by with plugins. Lint uses <a href="/pod/Module::Pluggable">Module::Pluggable</a> to find available plugins. Plugins are expected but not required to inform Lint of which checks they are adding.</p> <p>The <code>B::Lint->register_plugin( MyPlugin => \@new_checks )</code> method adds the list of <code>@new_checks</code> to the list of valid checks. If your module wasn't loaded by <a href="/pod/Module::Pluggable">Module::Pluggable</a> then your class name is added to the list of plugins.</p> <p>You must create a <code>match( \%checks )</code> method in your plugin class or one of its parents. It will be called on every op as a regular method call with a hash ref of checks as its parameter.</p> <p>The class methods <code>B::Lint->file</code> and <code>B::Lint->line</code> contain the current filename and line number.</p> <pre><code>package Sample; use B::Lint; B::Lint->register_plugin( Sample => [ 'good_taste' ] ); sub match { my ( $op, $checks_href ) = shift @_; if ( $checks_href->{good_taste} ) { ... } }</code></pre> <h1 id="TODO">TODO</h1> <dl> <dt id="while(<FH>)-stomps-$_"><a id="while"></a><a id="while-FH-stomps-_"></a>while(<FH>) stomps $_</dt> <dd> </dd> <dt id="strict-oo"><a id="strict"></a>strict oo</dt> <dd> </dd> <dt id="unchecked-system-calls"><a id="unchecked"></a>unchecked system calls</dt> <dd> </dd> <dt id="more-tests,-validate-against-older-perls"><a id="more"></a><a id="more-tests-validate-against-older-perls"></a>more tests, validate against older perls</dt> <dd> </dd> </dl> <h1 id="BUGS">BUGS</h1> <p>This is only a very preliminary version.</p> <h1 id="AUTHOR">AUTHOR</h1> <p>Malcolm Beattie, mbeattie@sable.ox.ac.uk.</p> <h1 id="ACKNOWLEDGEMENTS">ACKNOWLEDGEMENTS</h1> <p>Sebastien Aperghis-Tramoni - bug fixes</p></div> <div id="metacpan_install-instructions-dialog" class="modal fade"> <div class="modal-dialog"> <div class="modal-content"> <div class="modal-header"> <button type="button" class="close" data-dismiss="modal" aria-hidden="true">×</button> <h4 class="modal-title">Module Install Instructions</h4> </div> <div class="modal-body"> <p>To install B::Lint, copy and paste the appropriate command in to your terminal.</p> <p><a href="/dist/App-cpanminus/view/bin/cpanm">cpanm</a></p> <pre><code>cpanm B::Lint</code></pre> <p><a href="/pod/CPAN">CPAN shell</a></p> <pre><code>perl -MCPAN -e shell install B::Lint</code></pre> <p>For more information on module installation, please visit <a href="https://www.cpan.org/modules/INSTALL.html">the detailed CPAN module installation guide</a>.</p> </div> <div class="modal-footer"> <a href="#" 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