our $VERSION = '0.18';
sub new ( $class, @args ) {
my $pars = Ref::Util::is_hashref( $args[-1] ) ? pop @args : {};
$class->_throw( parameter => "incorrect number of arguments for sequence" )
if @args < 1 || @args > 3;
my %state;
$state{step} = pop @args if @args == 3;
$state{end} = pop @args;
$state{begin} = pop @args;
$class->SUPER::new( \%state, $pars );
}
sub construct ( $class, $state ) {
$class->_throw( parameter => "$class: arguments must be numbers\n" )
unless List::Util::all { Scalar::Util::looks_like_number( $_ ) };
my ( $begin, $end, $step, $iter, $next, $current, $prev )
= @{$state}{qw[ begin end step iter next current prev ]};
my $self;
my $iterator_state;
my %params;
if ( !defined $step ) {
$begin = 0 unless defined $begin;
$next = $begin unless defined $next;
%params = (
( +NEXT ) => sub {
if ( $next > $end ) {
$prev = $current
unless $self->is_exhausted;
return $current = $self->signal_exhaustion;
}
$prev = $current;
$current = $next++;
return $current;
},
( +FREEZE ) => sub {
[
$class,
{
begin => $begin,
end => $end,
prev => $prev,
current => $current,
next => $next,
},
]
},
);
}
else {
$class->_throw(
parameter => "sequence will be inifinite as \$step is zero or has the incorrect sign" )
if ( $begin < $end && $step <= 0 ) || ( $begin > $end && $step >= 0 );
$next = $begin unless defined $next;
$iter = 0 unless defined $iter;
%params = (
( +FREEZE ) => sub {
[
$class,
{
begin => $begin,
end => $end,
step => $step,
iter => $iter,
prev => $prev,
current => $current,
next => $next,
} ]
},
( +NEXT ) => $begin < $end
? sub {
if ( $next > $end ) {
$prev = $current
unless $self->is_exhausted;
return $current = $self->signal_exhaustion;
}
$prev = $current;
$current = $next;
$next = $begin + ++$iter * $step;
return $current;
}
: sub {
if ( $next < $end ) {
$prev = $current
unless $self->is_exhausted;
return $current = $self->signal_exhaustion;
}
$prev = $current;
$current = $next;
$next = $begin + ++$iter * $step;
return $current;
},
);
}
return {
%params,
( +CURRENT ) => sub { $current },
( +PREV ) => sub { $prev },
( +REWIND ) => sub {
$next = $begin;
$iter = 0;
},
( +RESET ) => sub {
$prev = $current = undef;
$next = $begin;
$iter = 0;
},
( +_SELF ) => \$self,
( +STATE ) => \$iterator_state,
};
}
__PACKAGE__->_add_roles( qw[
State::Closure
Next::ClosedSelf
Rewind::Closure
Reset::Closure
Prev::Closure
Current::Closure
Freeze
] );
1;