sub listToIndexedHashRef{ 
    my $n=0; 
    my %hash = map{ $n++, $_} @_; 
    return \%hash 
};;

my $hashRef = listToIndexedHash( qw[the quick brown fox ] );;

pp $hashRef;;
{ "0" => "the", 1 => "quick", 2 => "brown", 3 => "fox" }

sub listToIndexedList{ 
    my $n=0; 
    return map{ $n++, $_} @_; 
};;

my %hash = listToIndexedList( qw[the quick brown fox ] );;

pp \%hash;;
{ "0" => "the", 1 => "quick", 2 => "brown", 3 => "fox" }