NAME

       Perl::Critic::Policy::Variables::ProhibitPunctuationVars - Write "$EVAL_ERROR" instead of "$@".

AFFILIATION

       This Policy is part of the core Perl::Critic distribution.

DESCRIPTION

       Perl's vocabulary of punctuation variables such as $!, $., and $^ are perhaps the leading cause of its
       reputation as inscrutable line noise.  The simple alternative is to use the English module to give them
       clear names.

         $| = undef;                      #not ok

         use English qw(-no_match_vars);
         local $OUTPUT_AUTOFLUSH = undef; #ok

CONFIGURATION

       The scratch variables $_ and @_ are very common and are pretty well understood, so they are exempt from
       this policy.  The same goes for the less-frequently-used default filehandle "_" used by stat().  All the
       regexp capture variables ($1, $2, ...) are exempt too.  $] is exempt because there is no English
       equivalent and Module::CoreList is based upon it.

       You can add more exceptions to your configuration.  In your perlcriticrc file, add a block like this:

         [Variables::ProhibitPunctuationVars]
         allow = $@ $!

       The "allow" property  should  be  a  whitespace-delimited  list  of punctuation variables.

       Other configuration options  control  the  parsing  of  interpolated strings in the search for forbidden
       variables. They have  no  effect on detecting punctuation variables outside of interpolated  strings.

         [Variables::ProhibitPunctuationVars]
         string_mode = thorough

       The option "string_mode"  controls  whether  and  how  interpolated strings are searched for punctuation
       variables. Setting "string_mode = thorough", the default,  checks  for  special  cases that may look like
       punctuation variables  but  aren't,  for  example $#foo, an array index count; $$bar, a scalar
       dereference;  or $::baz, a global symbol.

       Setting "string_mode = disable" causes all interpolated strings  to be ignored entirely.

       Setting "string_mode = simple" uses a simple regular expression  to find matches. In this mode, the magic
       variables $$, "$'",  $# and $: are ignored within interpolated strings due  to  the  high risk of false
       positives. Simple mode is  retained  from  an  earlier draft of the interpolated- strings code. Its use
       is only recommended as a workaround if bugs appear in thorough mode.

       The  "string_mode"  option  will  go  away  when  the  parsing   of interpolated strings is implemented
       in PPI. See  "CAVEATS"  below.

BUGS

       Punctuation variables that confuse PPI's document parsing may not be detected  correctly  or  at  all,
       and  may  prevent  detection   of subsequent ones. In particular, $" is known to cause difficulties in
       interpolated strings.

CAVEATS

       ProhibitPunctuationVars  relies   exclusively   on   PPI   to   find punctuation variables in code, but
       does all the parsing  itself  for interpolated strings. When, at some  point,  this  functionality  is
       transferred to PPI, ProhibitPunctuationVars  will  cease  doing  the interpolating  and  the
       "string_mode"   option   will   go   away.

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.

perl v5.24.1                                       Perl::Critic::Policy::Variables::ProhibitPunctuationVars(3pm)