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# Copyright 2010, 2011, 2012, 2013, 2014, 2015, 2016, 2017 Kevin Ryde
# Perl-Critic-Pulp is free software; you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by the
# Free Software Foundation; either version 3, or (at your option) any later
# version.
#
# Perl-Critic-Pulp is distributed in the hope that it will be useful, but
# WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
# or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
# for more details.
#
# You should have received a copy of the GNU General Public License along
# with Perl-Critic-Pulp. If not, see <http://www.gnu.org/licenses/>.
package Perl::Critic::Policy::ValuesAndExpressions::ProhibitBarewordDoubleColon;
use 5.006;
use strict;
use warnings;
use List::Util;
use base 'Perl::Critic::Policy';
use Perl::Critic::Utils;
use Perl::Critic::Pulp;
use Perl::Critic::Pulp::Utils 'elem_is_comma_operator';
# uncomment this to run the ### lines
#use Smart::Comments;
our $VERSION = 96;
use constant supported_parameters =>
({ name => 'allow_indirect_syntax',
description => 'Whether to allow double-colon in indirect object syntax "new Foo:: arg,arg".',
behavior => 'boolean',
default_string => '1',
});
use constant default_severity => $Perl::Critic::Utils::SEVERITY_LOWEST;
use constant default_themes => qw(pulp cosmetic);
use constant applies_to => 'PPI::Token::Word';
sub violates {
my ($self, $elem, $document) = @_;
$elem =~ /::$/ or return;
if ($self->{'_allow_indirect_syntax'}) {
if (_word_is_indirect_call_classname($elem)) {
return;
}
}
return $self->violation
('Use plain string instead of Foo:: bareword',
'',
$elem);
}
# $elem is a PPI::Token::Word.
# Return true if it's the class name in an indirect object syntax method call.
#
sub _word_is_indirect_call_classname {
my ($elem) = @_;
### _word_is_indirect_call_classname(): "$elem"
my $prev = $elem->sprevious_sibling || do {
### no method preceding, not an indirect call ...
return 0;
};
### prev: ref $prev, $prev->content
if (! $prev->isa('PPI::Token::Word')) {
### not a bareword method name preceding, not an indirect call ...
return 0;
}
if ($prev eq 'return') {
### return is never an indirect call ...
return 0;
}
# What about "foo bar Foo::"? Assume its function foo and method bar?
#
# $prev = $prev->sprevious_sibling;
# ### prev-prev: ref $prev, $prev->content
# if ($prev && $prev->isa('PPI::Token::Word')) { return 0; }
if (my $next = $elem->snext_sibling) {
if ($next->isa('PPI::Token::Operator') && $next eq '=>') {
# "word1 word2 => ..." is either a function call to word1 or a syntax
# error, not an indirect call. But "word1 word2," can be an indirect
# call in a comma operator list
#
### fat comma not an indirect ...
return 0;
}
}
return 1;
}
1;
__END__
=for stopwords barewords bareword disambiguates ie runtime boolean Ryde
=head1 NAME
Perl::Critic::Policy::ValuesAndExpressions::ProhibitBarewordDoubleColon - don't use Foo:: style barewords
=head1 DESCRIPTION
This policy is part of the L<C<Perl::Critic::Pulp>|Perl::Critic::Pulp>
add-on. It asks you not to use the double-colon bareword like
$class = Foo::Bar::; # bad
but instead a plain string
$class = 'Foo::Bar'; # ok
This is intended as a building block for a restricted coding style, or a
matter of personal preference if you think the C<::> is a bit obscure and
that it's clearer to write a string when you mean a string. On that basis
the policy is lowest severity and under the "cosmetic" theme (see
L<Perl::Critic/POLICY THEMES>).
=head2 Indirect Object Syntax
By default a double-colon is allowed in the indirect object syntax (see
L<perlobj/Indirect Object Syntax>).
my $obj = new Foo::Bar:: $arg1,$arg2; # ok
This is because C<::> there is important to disambiguate a class name
C<Foo::Bar> from a function C<Foo::Bar()>, ie. function C<Bar()> in package
C<Foo>.
Whether you actually want indirect object syntax is a matter for other
policies, like
L<C<ProhibitIndirectSyntax>|Perl::Critic::Policy::Objects::ProhibitIndirectSyntax>.
If you don't want the double-colon bareword then change to arrow style
C<< Foo::Bar->new($arg,...) >>.
=head2 Double-Colon Advantages
The C<::> bareword is for use on package names, not general bareword
quoting. If there's no such package at compile time a warning is given (see
L<perldiag/Bareword "%s" refers to nonexistent package>)
my $class = No::Such::Package::; # Perl warning
This warning can help pick up typos, though it relies on relevant packages
being loaded at compile-time (ie. C<BEGIN>). If the package is loaded by a
C<require> at runtime then the warning fires even though the code runs
correctly. For reference, a warning isn't given for the indirect object
syntax, which rather limits its benefit.
=head2 Disabling
If you don't care about this you can always disable
C<ProhibitBarewordDoubleColon> from your F<.perlcriticrc> in the usual way
(see L<Perl::Critic/CONFIGURATION>),
[-ValuesAndExpressions::ProhibitBarewordDoubleColon]
=head1 CONFIGURATION
=over 4
=item C<allow_indirect_syntax> (boolean, default true)
If true then allow double-colon in the indirect object syntax as shown
above. If false then report double-colons everywhere as violations
# bad under allow_indirect_syntax=false
my $obj = new Foo::Bar:: $arg1,$arg2;
This can be controlled from your F<~/.perlcriticrc> in the usual way. For
example
[ValuesAndExpressions::ProhibitBarewordDoubleColon]
allow_indirect_syntax=no
=back
=head1 SEE ALSO
L<Perl::Critic::Pulp>,
L<Perl::Critic>,
L<Perl::Critic::Policy::Objects::ProhibitIndirectSyntax>
L<perl5005delta/"C<Foo::> can be used as implicitly quoted package name">
=head1 HOME PAGE
http://user42.tuxfamily.org/perl-critic-pulp/index.html
=head1 COPYRIGHT
Copyright 2010, 2011, 2012, 2013, 2014, 2015, 2016, 2017 Kevin Ryde
Perl-Critic-Pulp is free software; you can redistribute it and/or modify it
under the terms of the GNU General Public License as published by the Free
Software Foundation; either version 3, or (at your option) any later
version.
Perl-Critic-Pulp is distributed in the hope that it will be useful, but
WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
more details.
You should have received a copy of the GNU General Public License along with
Perl-Critic-Pulp. If not, see <http://www.gnu.org/licenses>.
=cut
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