Perl::Critic::Policy::InputOutput::ProhibitReadlineInForLoop(3)

NAME
Perl::Critic::Policy::InputOutput::ProhibitReadlineInForLoop - Write "while( $line = <> ){...}" instead of "for(<>){...}".

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

DESCRIPTION
Using the readline operator in a "for" or "foreach" loop is very slow. The iteration list of the loop creates a list context, which causes the readline operator to read the entire input stream before iteration even starts. Instead, just use a "while" loop, which only reads one line at a time.

  for my $line ( <$file_handle> ){ do_something($line) }      #not ok
  while ( my $line = <$file_handle> ){ do_something($line) }  #ok

CONFIGURATION
This Policy is not configurable except for the standard options.

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.