NAME¶
Perl::Critic::Policy::InputOutput::ProhibitExplicitStdin - Use
"<>" or "<ARGV>" or a prompting module instead
of "<STDIN>".
AFFILIATION¶
This Policy is part of the core Perl::Critic distribution.
DESCRIPTION¶
Perl has a useful magic filehandle called *ARGV that checks the command line and
if there are any arguments, opens and reads those as files. If there are no
arguments, *ARGV behaves like *STDIN instead. This behavior is almost always
what you want if you want to create a program that reads from
"STDIN". This is often written in one of the following two
equivalent forms:
while (<ARGV>) {
# ... do something with each input line ...
}
# or, equivalently:
while (<>) {
# ... do something with each input line ...
}
If you want to prompt for user input, try special purpose modules like
IO::Prompt.
CONFIGURATION¶
This Policy is not configurable except for the standard options.
CAVEATS¶
Due to a bug in the current version of PPI (v1.119_03) and earlier, the readline
operator is often misinterpreted as less-than and greater-than operators after
a comma. Therefore, this policy misses important cases like
my $content = join '', <STDIN>;
because it interprets that line as the nonsensical statement:
my $content = join '', < STDIN >;
When that PPI bug is fixed, this policy should start catching those violations
automatically.
CREDITS¶
Initial development of this policy was supported by a grant from the Perl
Foundation.
AUTHOR¶
Chris Dolan <cdolan@cpan.org>
COPYRIGHT¶
Copyright (c) 2007-2011 Chris Dolan. Many 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