mingw/html/lib/B/Lint.html

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  13 <big><strong><span class="block">&nbsp;B::Lint - Perl lint</span></strong></big>
  14 </td></tr>
  15 </table>
  16
  17 <p><a name="__index__"></a></p>
  18 <!-- INDEX BEGIN -->
  19
  20 <ul>
  21
  22         <li><a href="#name">NAME</a></li>
  23         <li><a href="#synopsis">SYNOPSIS</a></li>
  24         <li><a href="#description">DESCRIPTION</a></li>
  25         <li><a href="#options_and_lint_checks">OPTIONS AND LINT CHECKS</a></li>
  26         <li><a href="#non_lintcheck_options">NON LINT-CHECK OPTIONS</a></li>
  27         <li><a href="#bugs">BUGS</a></li>
  28         <li><a href="#author">AUTHOR</a></li>
  29 </ul>
  30 <!-- INDEX END -->
  31
  32 <hr />
  33 <p>
  34 </p>
  35 <h1><a name="name">NAME</a></h1>
  36 <p>B::Lint - Perl lint</p>
  37 <p>
  38 </p>
  39 <hr />
  40 <h1><a name="synopsis">SYNOPSIS</a></h1>
  41 <p>perl -MO=Lint[,OPTIONS] foo.pl</p>
  42 <p>
  43 </p>
  44 <hr />
  45 <h1><a name="description">DESCRIPTION</a></h1>
  46 <p>The B::Lint module is equivalent to an extended version of the <strong>-w</strong>
  47 option of <strong>perl</strong>. It is named after the program <em>lint</em> which carries
  48 out a similar process for C programs.</p>
  49 <p>
  50 </p>
  51 <hr />
  52 <h1><a name="options_and_lint_checks">OPTIONS AND LINT CHECKS</a></h1>
  53 <p>Option words are separated by commas (not whitespace) and follow the
  54 usual conventions of compiler backend options. Following any options
  55 (indicated by a leading <strong>-</strong>) come lint check arguments. Each such
  56 argument (apart from the special <strong>all</strong> and <strong>none</strong> options) is a
  57 word representing one possible lint check (turning on that check) or
  58 is <strong>no-foo</strong> (turning off that check). Before processing the check
  59 arguments, a standard list of checks is turned on. Later options
  60 override earlier ones. Available options are:</p>
  61 <dl>
  62 <dt><strong><a name="item_context"><strong>context</strong></a></strong>
  63
  64 <dd>
  65 <p>Produces a warning whenever an array is used in an implicit scalar
  66 context. For example, both of the lines</p>
  67 </dd>
  68 <dd>
  69 <pre>
  70     $foo = length(@bar);
  71     $foo = @bar;</pre>
  72 </dd>
  73 <dd>
  74 <p>will elicit a warning. Using an explicit <strong>scalar()</strong> silences the
  75 warning. For example,</p>
  76 </dd>
  77 <dd>
  78 <pre>
  79     $foo = scalar(@bar);</pre>
  80 </dd>
  81 </li>
  82 <dt><strong><a name="item_implicit_2dread_and_implicit_2dwrite"><strong>implicit-read</strong> and <strong>implicit-write</strong></a></strong>
  83
  84 <dd>
  85 <p>These options produce a warning whenever an operation implicitly
  86 reads or (respectively) writes to one of Perl's special variables.
  87 For example, <strong>implicit-read</strong> will warn about these:</p>
  88 </dd>
  89 <dd>
  90 <pre>
  91     /foo/;</pre>
  92 </dd>
  93 <dd>
  94 <p>and <strong>implicit-write</strong> will warn about these:</p>
  95 </dd>
  96 <dd>
  97 <pre>
  98     s/foo/bar/;</pre>
  99 </dd>
 100 <dd>
 101 <p>Both <strong>implicit-read</strong> and <strong>implicit-write</strong> warn about this:</p>
 102 </dd>
 103 <dd>
 104 <pre>
 105     for (@a) { ... }</pre>
 106 </dd>
 107 </li>
 108 <dt><strong><a name="item_bare_2dsubs"><strong>bare-subs</strong></a></strong>
 109
 110 <dd>
 111 <p>This option warns whenever a bareword is implicitly quoted, but is also
 112 the name of a subroutine in the current package. Typical mistakes that it will
 113 trap are:</p>
 114 </dd>
 115 <dd>
 116 <pre>
 117     use constant foo =&gt; 'bar';
 118     @a = ( foo =&gt; 1 );
 119     $b{foo} = 2;</pre>
 120 </dd>
 121 <dd>
 122 <p>Neither of these will do what a naive user would expect.</p>
 123 </dd>
 124 </li>
 125 <dt><strong><a name="item_dollar_2dunderscore"><strong>dollar-underscore</strong></a></strong>
 126
 127 <dd>
 128 <p>This option warns whenever <a href="file://C|\msysgit\mingw\html/pod/perlvar.html#item___"><code>$_</code></a> is used either explicitly anywhere or
 129 as the implicit argument of a <strong>print</strong> statement.</p>
 130 </dd>
 131 </li>
 132 <dt><strong><a name="item_private_2dnames"><strong>private-names</strong></a></strong>
 133
 134 <dd>
 135 <p>This option warns on each use of any variable, subroutine or
 136 method name that lives in a non-current package but begins with
 137 an underscore (``_''). Warnings aren't issued for the special case
 138 of the single character name ``_'' by itself (e.g. <a href="file://C|\msysgit\mingw\html/pod/perlvar.html#item___"><code>$_</code></a> and <a href="file://C|\msysgit\mingw\html/pod/perlvar.html#item___"><code>@_</code></a>).</p>
 139 </dd>
 140 </li>
 141 <dt><strong><a name="item_undefined_2dsubs"><strong>undefined-subs</strong></a></strong>
 142
 143 <dd>
 144 <p>This option warns whenever an undefined subroutine is invoked.
 145 This option will only catch explicitly invoked subroutines such
 146 as <code>foo()</code> and not indirect invocations such as <code>&amp;$subref()</code>
 147 or <code>$obj-&gt;meth()</code>. Note that some programs or modules delay
 148 definition of subs until runtime by means of the AUTOLOAD
 149 mechanism.</p>
 150 </dd>
 151 </li>
 152 <dt><strong><a name="item_regexp_2dvariables"><strong>regexp-variables</strong></a></strong>
 153
 154 <dd>
 155 <p>This option warns whenever one of the regexp variables <a href="file://C|\msysgit\mingw\html/pod/perlvar.html#item___"><code>$`</code></a>, <a href="file://C|\msysgit\mingw\html/pod/perlvar.html#item___"><code>$&amp;</code></a> or <a href="file://C|\msysgit\mingw\html/pod/perlvar.html#item___"><code>$'</code></a>
 156 is used. Any occurrence of any of these variables in your
 157 program can slow your whole program down. See <a href="file://C|\msysgit\mingw\html/pod/perlre.html">the perlre manpage</a> for
 158 details.</p>
 159 </dd>
 160 </li>
 161 <dt><strong><a name="item_all"><strong>all</strong></a></strong>
 162
 163 <dd>
 164 <p>Turn all warnings on.</p>
 165 </dd>
 166 </li>
 167 <dt><strong><a name="item_none"><strong>none</strong></a></strong>
 168
 169 <dd>
 170 <p>Turn all warnings off.</p>
 171 </dd>
 172 </li>
 173 </dl>
 174 <p>
 175 </p>
 176 <hr />
 177 <h1><a name="non_lintcheck_options">NON LINT-CHECK OPTIONS</a></h1>
 178 <dl>
 179 <dt><strong><a name="item__2du_package"><strong>-u Package</strong></a></strong>
 180
 181 <dd>
 182 <p>Normally, Lint only checks the main code of the program together
 183 with all subs defined in package main. The <strong>-u</strong> option lets you
 184 include other package names whose subs are then checked by Lint.</p>
 185 </dd>
 186 </li>
 187 </dl>
 188 <p>
 189 </p>
 190 <hr />
 191 <h1><a name="bugs">BUGS</a></h1>
 192 <p>This is only a very preliminary version.</p>
 193 <p>This module doesn't work correctly on thread-enabled perls.</p>
 194 <p>
 195 </p>
 196 <hr />
 197 <h1><a name="author">AUTHOR</a></h1>
 198 <p>Malcolm Beattie, <a href="mailto:mbeattie@sable.ox.ac.uk.">mbeattie@sable.ox.ac.uk.</a></p>
 199 <table border="0" width="100%" cellspacing="0" cellpadding="3">
 200 <tr><td class="block" style="background-color: #cccccc" valign="middle">
 201 <big><strong><span class="block">&nbsp;B::Lint - Perl lint</span></strong></big>
 202 </td></tr>
 203 </table>
 204
 205 </body>
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