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# Copyright 2013, 2014, 2015, 2016, 2017, 2019, 2021 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/>.
# perlcritic -s ProhibitIfIfSameLine /usr/share/perl5/Pod/Simple.pm
# preceded by "return" so actually ok
# perlcritic -s ProhibitIfIfSameLine /usr/share/perl5/Tk/AbstractCanvas.pm
# two ifs one line
package Perl::Critic::Policy::CodeLayout::ProhibitIfIfSameLine;
use 5.006;
use strict;
use warnings;
use Perl::Critic::Utils;
use base 'Perl::Critic::Policy';
our $VERSION = 99;
# uncomment this to run the ### lines
# use Smart::Comments;
use constant supported_parameters => ();
use constant default_severity => $Perl::Critic::Utils::SEVERITY_MEDIUM;
use constant default_themes => qw(pulp bugs);
use constant applies_to => ('PPI::Statement::Compound');
my %compound_type_is_if = (if => 1,
unless => 1);
sub violates {
my ($self, $elem, $document) = @_;
### ProhibitIfIfSameLine elem: "$elem"
### type: $elem->type
unless (_compound_statement_is_if($elem)) {
### not an "if" ...
return;
}
if (_elems_any_separator ($elem->child(0), $elem->schild(0))) {
### leading whitespace in elem itself, so ok ...
return;
}
my $prev = $elem->sprevious_sibling || return;
unless ($prev->isa('PPI::Statement::Compound')
&& $compound_type_is_if{$prev->type}) {
### not preceded by an "if", so ok ...
return;
}
if (_elems_any_separator ($prev->next_sibling, $elem)) {
### newlines after previous statement, so ok ...
return;
}
return $self->violation
('Put a newline in "} if (x)" so it doesn\'t look like possible \"elsif\"',
'',
$elem);
}
# $elem is a PPI::Statement::Compound
# Return true if it's an "if" statement.
# Note this is not simply $elem->type eq "if", since type "if" includes
# "unless" statements, but _compound_statement_is_if() is true only on "if"
# statements.
#
sub _compound_statement_is_if {
my ($elem) = @_;
return (($elem->schild(0)||'') eq 'if');
}
# Return true if there is a suitable separator in $from or its following
# elements up to $to, but not including $to.
#
sub _elems_any_separator {
my ($from, $to) = @_;
for (;;) {
if ($from == $to) {
return 0;
}
if ($from =~ /\n/
|| $from->isa('PPI::Statement::Null')) {
return 1;
}
$from = $from->next_sibling || return 0;
}
}
1;
__END__
=for stopwords Ryde
=head1 NAME
Perl::Critic::Policy::CodeLayout::ProhibitIfIfSameLine - don't put if after if on same line
=head1 DESCRIPTION
This policy is part of the L<C<Perl::Critic::Pulp>|Perl::Critic::Pulp>
add-on. It asks you to not to write an C<if> statement on the same line as
a preceding C<if>.
if ($x) {
...
} if ($y) { # bad
...
}
if ($x) {
...
} elsif ($y) { # was "elsif" intended ?
...
}
The idea is that an C<if> in the layout of an C<elsif> may be either a
mistake or will be confusing to a human reader. On that basis this policy
is under the "bugs" theme and medium severity (see L<Perl::Critic/POLICY
THEMES>).
=head2 Unless
An C<unless...if> is treated the same. Perl allows C<unless ... elsif> and
so the same potential confusion with an C<elsif> layout arises.
unless ($x) {
...
} if ($y) { # bad
...
}
unless ($x) {
...
} elsif ($y) { # maybe meant to be "elsif" like this ?
...
}
Whether C<unless ... elsif> is a good idea at all is another matter.
Sometimes it suits a combination of conditions.
=head2 Statement Modifiers
This policy only applies to a statement followed by a statement. An C<if>
as a statement modifier is not affected. It's usual to put that on the same
line as the statement it modifies.
do {
...
} if ($x); # ok, statement modifier
=head2 All One Line
Two C<if> statements written on the same line will trigger the policy.
if(1){one;} if(2){two;} # bad
Perhaps there could be an exception or option when both statements are
entirely on the one line, or some such, for code which is trying to be
compact.
=head2 Disabling
As always if you don't care about this then you can disable
C<ProhibitIfIfSameLine> from your F<.perlcriticrc> (see
L<Perl::Critic/CONFIGURATION>),
[-CodeLayout::ProhibitIfIfSameLine]
=head1 SEE ALSO
L<Perl::Critic::Pulp>, L<Perl::Critic>
L<Perl::Critic::Policy::ControlStructures::ProhibitCascadingIfElse>,
L<Perl::Critic::Policy::ControlStructures::ProhibitUnlessBlocks>
=head1 HOME PAGE
L<http://user42.tuxfamily.org/perl-critic-pulp/index.html>
=head1 COPYRIGHT
Copyright 2013, 2014, 2015, 2016, 2017, 2019, 2021 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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