NAME

       Perl::Critic::Policy::ValuesAndExpressions::NotWithCompare - logical not used with compare

DESCRIPTION

       This policy is part of the "Perl::Critic::Pulp" add-on.  It picks up some cases of logical
       not "!" used with a comparison, like

           ! $x =~ /^[123]/  # bad
           ! $x + $y >= $z   # bad

       In each case precedence means Perl parses this as "(!$x)", like

           (! $x) =~ /^[123]/
           (! $x) + $y >= $z

       rather than a negated comparison.  Usually this is a mistake, so this policy is under the
       "bugs" theme (see "POLICY THEMES" in Perl::Critic).

       As a special case, "!" on both sides of "==" or "!=" is allowed, since it's quite a good
       way to compare booleans.

           !$x == !$y   # ok
           !$x != !$y   # ok

LIMITATIONS

       User functions called without parentheses are assumed to be usual varargs style.  But a
       prototype may mean that's not the case, letting a bad "!"-with-compare expression to go
       undetected.

           ! userfunc $x == 123   # indeterminate
           # without prototype would be ok:   ! (userfunc ($x==123))
           # with ($) prototype would be bad: (! userfunc($x)) == 123

       Perl builtins with no args, and constant subs created with "use constant" or "sub FOO ()
       {...}" in the file under test are recognised.  Hopefully anything else too weird is rare.

           ! time == 1   # bad

           use constant FIVE => 5;
           ! FIVE < 1    # bad

           sub name () { "foo" }
           ! name =~ /bar/    # bad

SEE ALSO

       Perl::Critic::Pulp, Perl::Critic

HOME PAGE

       http://user42.tuxfamily.org/perl-critic-pulp/index.html

COPYRIGHT

       Copyright 2008, 2009, 2010, 2011, 2012, 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/>.

perl v5.32.1                      Perl::Critic::Policy::ValuesAndExpressions::NotWithCompare(3pm)