#normal sub
sub foo { 
  return join ("#",@_);
}

{ #Anon block for static vars to live in.
  my $join="-";
  sub bar {
    my $ret=join($join,@_);
    $join=($join eq "-") ? ":" : "-";
    return $ret;
  } 

} # End static block

print foo(1..10),"\n";
print foo(1..10),"\n";
print bar(1..10),"\n";
print bar(1..10),"\n";
print bar(1..10),"\n";
__END__
1#2#3#4#5#6#7#8#9#10
1#2#3#4#5#6#7#8#9#10
1-2-3-4-5-6-7-8-9-10
1:2:3:4:5:6:7:8:9:10
1-2-3-4-5-6-7-8-9-10