Perl::Critic::Policy::ValuesAndExpressions::ProhibitArrayAssignAref - don't assign an anonymous arrayref to an array
This policy is part of the Perl::Critic::Pulp addon. It asks you not to assign an anonymous arrayref to an array
Perl::Critic::Pulp
@array = [ 1, 2, 3 ]; # bad
The idea is that it's a rather unclear whether an arrayref is intended, or might have meant a list like
@array = ( 1, 2, 3 );
For the chance the [] is a mistake and since it will make anyone reading it wonder, this policy is under the "bugs" theme (see "POLICY THEMES" in Perl::Critic).
[]
It's perfectly good to assign a single arrayref to an array, but put parens to make it clear,
@array = ( [1,2,3] ); # ok
Derefs and array and hash slices (see "Slices" in perldata) are recognised and treated likewise,
@$ref = [1,2,3]; # bad to deref @{$ref} = [1,2,3]; # bad to deref @x[1,2,3] = ['a','b','c']; # bad to array slice @x{'a','b'} = [1,2]; # bad to hash slice
There's no blanket requirement for () parens on an array assignment here since it's normal and unambiguous to have a function call or grep etc.
()
grep
@array = foo(); @array = grep {/\.txt$/} @array;
The only likely problem from lack of parens is that the , comma operator has lower precedence than = (see perlop), so something like
,
=
@array = 1,2,3; # not a list
means
@array = (1); 2; 3;
Normally the remaining literals in void context provoke a compile time warning.
An intentional single element assignment is quite common though, as a statement, for instance
@ISA = 'My::Parent::Class';
For reference the range operator precedence is high enough,
@array=1..10; # fine
though of course parens are needed if concatenating some disjoint ranges with the comma operator,
@array = (1..5, 10..15); # parens needed
The qw form gives a list too
qw
@array = qw(a b c); # fine
Perl::Critic::Pulp, Perl::Critic
http://user42.tuxfamily.org/perl-critic-pulp/index.html
Copyright 2011 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>.
To install Perl::Critic::Pulp, copy and paste the appropriate command in to your terminal.
cpanm
cpanm Perl::Critic::Pulp
CPAN shell
perl -MCPAN -e shell install Perl::Critic::Pulp
For more information on module installation, please visit the detailed CPAN module installation guide.