use 5.010001;
use strict;
use Perl::Critic::Utils qw{ :severities :classification };
our $VERSION = '1.152';
#-----------------------------------------------------------------------------
Readonly::Scalar my $DESC => q{Map blocks should have a single statement};
Readonly::Scalar my $EXPL => [ 113 ];
#-----------------------------------------------------------------------------
sub supported_parameters {
return (
{
name => 'max_statements',
description =>
'The maximum number of statements to allow within a map block.',
default_string => '1',
behavior => 'integer',
integer_minimum => 1,
},
);
}
sub default_severity { return $SEVERITY_MEDIUM }
sub default_themes { return qw( core pbp maintenance complexity) }
sub applies_to { return 'PPI::Token::Word' }
#-----------------------------------------------------------------------------
sub violates {
my ( $self, $elem, undef ) = @_;
return if $elem->content() ne 'map';
return if ! is_function_call($elem);
my $sib = $elem->snext_sibling();
return if !$sib;
my $arg = $sib;
if ( $arg->isa('PPI::Structure::List') ) {
$arg = $arg->schild(0);
# Forward looking: PPI might change in v1.200 so schild(0) is a PPI::Statement::Expression
if ( $arg && $arg->isa('PPI::Statement::Expression') ) {
$arg = $arg->schild(0);
}
}
# If it's not a block, it's an expression-style map, which is only one statement by definition
return if !$arg;
return if !$arg->isa('PPI::Structure::Block');
# If we get here, we found a sort with a block as the first arg
return if $self->{_max_statements} >= $arg->schildren()
&& 0 == grep {$_->isa('PPI::Statement::Compound')} $arg->schildren();
# more than one child statements
return $self->violation( $DESC, $EXPL, $elem );
}
1;
#-----------------------------------------------------------------------------
__END__
=pod
=head1 NAME
Perl::Critic::Policy::BuiltinFunctions::ProhibitComplexMappings - Map blocks should have a single statement.
=head1 AFFILIATION
This Policy is part of the core L<Perl::Critic|Perl::Critic>
distribution.
=head1 DESCRIPTION
The map function can be confusing to novices in the best of
circumstances. Mappings with multiple statements are even worse.
They're also a maintainer's nightmare because any added complexity
decreases readability precipitously. Why? Because map is
traditionally a one-liner converting one array to another. Trying to
cram lots of functionality into a one-liner is a bad idea in general.
The best solutions to a complex mapping are: 1) write a subroutine
that performs the manipulation and call that from map; 2) rewrite the
map as a for loop.
=head1 CAVEATS
This policy currently misses some compound statements inside of the
map. For example, the following code incorrectly does not trigger a
violation:
map { do { foo(); bar() } } @list
=head1 CONFIGURATION
By default this policy flags any mappings with more than one
statement. While we do not recommend it, you can increase this limit
as follows in a F<.perlcriticrc> file:
[BuiltinFunctions::ProhibitComplexMappings]
max_statements = 2
=head1 AUTHOR
Chris Dolan <cdolan@cpan.org>
=head1 CREDITS
Initial development of this policy was supported by a grant from the
Perl Foundation.
=head1 COPYRIGHT
Copyright (c) 2007-2011 Chris Dolan.
This program is free software; you can redistribute it and/or modify
it under the same terms as Perl itself.
=cut
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