Overview - Chapter: 0:Intr, 1:Hist, 2:Design, 3:Var, 4:Op, 5:IO, 6:{}, 7:Sub, 8:OOP, 9:Rx - Appendices: A:Index, B:Tables, C:Best of, D:Delta, E:Links

This is a small tour, showing the best features and improvements of Perl 6 in short examples, compared to similar working Perl 5 examples.

Command Line

Making output will become simpler and easier for newbies.

               Perl 5                                     Perl 6 
 print "bananas are good\n";                     say "bananas are good";
 print "and I said: $quotes{\"me\"}\n";          say "and I said: %quotes{"me"}.";
 print "and I said: $quotes{\"me\"}\n";          say "and I said: %quotes<me>.";
 print "What is ... ";                           $result = prompt "What is ... ";
 chomp($result = <>);

File IO

File::Slurp is in the Perl 6 core language and file reading is simpler then ever (and autochomp included).

               Perl 5                                     Perl 6 
 $content = do { local $/;                       $content = slurp "poetry.txt";
    open my $FH, "poetry.txt"; <$FH>
 };

chomp(@content = do {                            @content = lines "poetry.txt";
    open my $FH, "poetry.txt"; <$FH>
});

Automatic multithreading

Applying operations to junctions and arrays is now syntactically compact and readable. Perl 6 will create threads where appropriate to use multiple processors, cores or hyperthreading for high level language SIMD concurrent processing.

               Perl 5                                     Perl 6 
 my $sum;                                        my $sum = [+] @numbers;
 $sum += $_ for @numbers;
 for (0 .. $#factor1) {                          @product = @factor1 >>*<< @factor2;
   $product[$] = $factor1[$] * $factor2[$_];
 }

The Perl 5 code is a simplification, of course Perl6 "does the right thing" when the arrays have different lengths.

Comparsion

Here are junctions, then chained comparison operators.

               Perl 5                                     Perl 6 
 if ($a = 3 or $a = 4 or $a = 7) {...}           if $a = 3 | 4 | 7 {...}
 if (4 < $a and $a < 12) {...}                   if 4 < $a < 12 {...} 
 if (4 < $a and $a <= 12) {...}                  if $a ~~ 4^..12 {...}
 $a = defined $b ? $b : $c;                      $a = $b // $c;

The defined-OR operator eases lot of cases where Perl 5 newbies could fall into traps.

Case construct

               Perl 5                                      Perl 6 
                                                     given $a {
 if ($a = 2 or $a = 5) {...} }}                        when 2 | 5 {...}
 elsif ($a = 6 or $a = 7 or $a = 8 or $a = 9) {...}    when 6 .. 9 {...} 
 elsif ($a =~ /g/) {...}                               when 'g' {...}
 else {...}                                            default {...}
                                                     }

It's clear to read, very versatile and when used in combination with junctions, becomes even clearer.

powerful for loops

               Perl 5                                     Perl 6 
 for my $i (1..15) {...}                         for 1..15 -> $i {...}
 for (my $i=15; $i>1; $i-2) {...}                for 15,*-2...1 -> $i {...}
 for my $key (keys %hash) {                      for %hash.kv -> $key, $value {
   print "$key => $hash{$key}\n"; ...              say "$key => $value"; ...
 for my $i (0..$#a) {                            for zip(@a; @b; @c)- > $a, $b, $c {...}
   my $a = @a[$i];
   my $b = @b[$i];
   my $c = @c[$i]; ... 

named parameters in subroutines

               Perl 5                                     Perl 6 
 sub routine {                                   sub routine ($a, $b, *@rest) {...}
   my $a = shift;
   my $b = shift;
   my @rest = @_;
 }

Objects with auto generated new and getters and setters

Simple Object creation is now as easy as it gets.

               Perl 5                                     Perl 6 
 package Heart::Gold;                            class Heart::Gold {
                                                   has $.speed;
 sub new {                                         method stop { $.speed = 0 }      
   bless {speed => 0 }, shift;                   }  
 }                                               
                                                 my Heart::Gold $hg1 .= new;
 sub speed {                                     $hg1.speed = 100;
   my $self = shift;                             my $hg2 = $hg1.clone;
   my $speed = shift;
   if (defined $speed) { $self->{speed} = $speed }
   else { $self->{speed} }
 }

 sub stop {
   my $self = shift; 
   $self->{speed} = 0;
 }

The new, getter, setter and clone methods are auto generated. Mthods now are called "method".

Overview - Chapter: 0:Intr, 1:Hist, 2:Design, 3:Var, 4:Op, 5:IO, 6:{}, 7:Sub, 8:OOP, 9:Rx - Appendices: A:Index, B:Tables, C:Best of, D:Delta, E:Links