Perl::Critic::Policy::Variables::ProhibitPunctuationVarsUser Contributed Perl DocumentaPerl::Critic::Policy::Variables::ProhibitPunctuationVars(3)

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 v5.16.3							    2014-06-09	       Perl::Critic::Policy::Variables::ProhibitPunctuationVars(3)