NAME
Perl::Critic::Policy::Plicease::ProhibitArrayAssignAref - Don't assign an anonymous arrayref to an array
VERSION
version 100.00
DESCRIPTION
This policy is a fork of Perl::Critic::Policy::ValuesAndExpressions::ProhibitArrayAssignAref. It differs from the original by not having a dependency on List::MoreUtils. It is unfortunately still licensed as GPL3.
It asks you not to assign an anonymous arrayref to an array
@array= [ 1, 2, 3 ];# bad
The idea is that it's rather unclear whether an arrayref is intended, or might have meant to be a list like
@array= ( 1, 2, 3 );
This policy is under the "bugs" theme (see "POLICY THEMES" in Perl::Critic) for the chance [] is a mistake, and since even if it's correct it will likely make anyone reading it wonder.
A single arrayref can still be assigned to an array, but with parens to make it clear,
@array= ( [1,2,3] );# ok
Dereferences or array and hash slices (see "Slices" in perldata) are recognised as an array target and treated similarly,
@$ref= [1,2,3];# bad assign to deref@{$ref} = [1,2,3];# bad assign to deref@x[1,2,3] = ['a','b','c'];# bad assign to array slice@x{'a','b'} = [1,2];# bad assign to hash slice
List Assignment Parens
This policy is not a blanket requirement for () parens on array assignments. It's normal and unambiguous to have a function call or grep etc without parens.
@array= foo();# ok@array=grep{/\.txt$/}@array;# ok
The only likely problem from lack of parens in such cases is that the , comma operator has lower precedence than = (see perlop), so something like
@array= 1,2,3;# oops, not a list
means
@array= (1);2;3;
Normally the remaining literals in void context provoke a warning from Perl itself.
An intentional single element assignment is quite common as a statement, for instance
@ISA='My::Parent::Class';# ok
And for reference the range operator precedence is high enough,
@array= 1..10;# ok
But 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
@array=qw(a b c);# ok
SEE ALSO
HOME PAGE
COPYRIGHT
Copyright 2011, 2012, 2013, 2014, 2015, 2016, 2017, 2019, 2021 Kevin Ryde
Perl-Critic-Policy-Plicease-ProhibitArrayAssignAref 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-Policy-Plicease-ProhibitArrayAssignAref 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-Policy-Plicease-ProhibitArrayAssignAref. If not, see <http://www.gnu.org/licenses>.
AUTHOR
Original author: Kevin Ryde
Current maintainer: Graham Ollis <plicease@cpan.org>
COPYRIGHT AND LICENSE
This software is Copyright (c) 2011-2021 by Kevin Ryde.
This is free software, licensed under:
The GNU General Public License, Version 3, June 2007