Subs return lists; and both hashes and arrays flatten to lists. The only problematic one is the scalar:

#! perl -slw
use strict;
use Data::Dump qw[ pp ];

sub func {
    my $arg = shift;
    my %hash = 'a'..'f';
    my @array = 0..9;
    my $scalar = 'scalar';
    $arg == 1 and return %hash;
    $arg == 2 and return @array;
    $arg == 3 and return $scalar;
}

sub wrapper {
    my @rv = func( @_ );
    return @rv == 1 ? $rv[ 0 ] : @rv;
}

my %hash = wrapper( 1 ); pp \%hash;
my @array = wrapper( 2 ); pp\@array;;
my $scalar = wrapper( 3 ); pp $scalar;

__END__
c:\test>junk12
{ a => "b", c => "d", e => "f" }

[0, 1, 2, 3, 4, 5, 6, 7, 8, 9]

"scalar"
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Of course, if you want to find out the current bucket allocation of the hash, or retrieve the last item of the array; you'll need to assign it to the appropriate variable in the calling code first.