Why I’m Learning Perl 6(evanmiller.org)

    sub add( $arg1, $arg2 ) {
        $arg1 + $arg2;
    }

    fun add( Num $arg1, Num $arg2 ) {
        $arg1 + $arg2;
    }

  use Params::Validate 'validate';
  sub add2 {
    my $self = shift;
    my $args = validate (@_, { ... } ); 
  }

  my $calc_functions = {
    'add' => sub { $_[0] + $_[1] },
    'subtract' => sub { $_[0] - $_[1] },
    ...
  };
  my $func = 'add';
  $calc_functions->{$func}->($args);

  # break the aliasing of @_ and make undef into 0.
  sub undef_to_zero { @_ = map { $_ // 0 } @_; }

  sub math_stuff {
    # call with identical @_
    &undef_to_zero;
    # Do math without undef warnings.
    my $sum = 0;
    $sum += $_ for @_;
  }

  # Alter all arguments in calls by repeating them
  sub fatten {
    $_ = "$_" x 2 for @_;
  }

  $foo = "abc";
  @bar = ( 1, 2, 4 );
  foo($foo, @bar);
  say $foo; # abcabc
  say for @bar # 11
               # 22
               # 44

    def add1(*_):
        _ = list(_)

        arg1, arg2 = _
        return arg1 + arg2

    def add2(*_):
        _ = list(_)

        arg1 = _.pop(0)
        arg2 = _.pop(0)
        return arg1 + arg2

    def add3(*_):
        _ = list(_)

        return _[0] + _[1]

   stringliteral:   shortstring | longstring
   shortstring:     "'" shortstringitem* "'" | '"' shortstringitem* '"'
   longstring:      "'''" longstringitem* "'''" | '"""' longstringitem* '"""'
   shortstringitem: shortstringchar | escapeseq
   longstringitem:  longstringchar | escapeseq
   shortstringchar: <any ASCII character except "\" or newline or the quote>
   longstringchar:  <any ASCII character except "\">
   escapeseq:       "\" <any ASCII character>

    Usenet article <[email protected]> (1992) -- Larry Wall