# Perl 6 :)

sub restart_server (Str +$host, Int +$port, Int +$timeout) {
  ...;
}

# Call using
restart_server host => "...", port => ..., timeout => ...;
# or
restart_server :host«...», :port(...), :timeout(...);

##</code><code>##

# Perl 5
sub foo {
  my $a = shift;
  ...;
}

##</code><code>##

sub foo {
  my ($a, $b, $c, $d) = @_;
  ...;
}

##</code><code>##

sub foo {
  my %args = @_;
  my ($a, $b, $c, $d) = @args{qw( a b c d )};
  # Or:
  my ($a, $b, $c, $d) = @{{@_}}{qw( a b c d )};
  ...;
}