Raku Programming Language

Q: There are new versions of Perl, and I mean Raku (Perl 6). Perl 1, which is being developed here, is retro software. Can you give us some examples of Raku programming?

A: Yes, Perl 1 comes from the year 1987, and Raku is from 2018. That seems like 31 years of development. Here are examples of Raku programming taken from a modern Perl course. Examples have an example usage, the source code, and an example output (or interactive session).

./name.raku

#!/usr/bin/env raku
use v6.d;

sub MAIN() {
        my $name = prompt "Wie ist deine Name? ";
        say "Willkommen, ", $name, "!"
}

Wie ist deine Name? Matze
Willkommen, Matze!

./nummer_vermutung.raku 50

#!/usr/bin/env raku
use v6.d;

sub MAIN($maximum = 100) {
        my $geheimnummer = $maximum.rand.Int;
        say "Hinweis: ", $geheimnummer;

        loop {
                my $vermutung = prompt "Wie ist die Nummer? ";
                last unless $vermutung != $geheimnummer;

                if ($vermutung < $geheimnummer) {
                        say "Falsch. Es ist zu wenig.";
                } else {
                        say "Falsch. Es ist zu viel.";
                }

        }

        say "Richtig!";
}

Hinweis: 37
Wie ist die Nummer? 33
Falsch. Es ist zu wenig.
Wie ist die Nummer? 44
Falsch. Es ist zu viel.
Wie ist die Nummer? 37
Richtig!

./umkehren.raku perl

#!/usr/bin/env raku
use v6.d;

# Hier können Sie Ihre Mitteilung geben.

sub MAIN($mitteilung) {
    # Kehr die Mitteilung um.

    loop (my $i = $mitteilung.chars - 1; $i >= 0; $i--) {
        say substr $mitteilung, $i, 1
    }

 }

l
r
e
p

./chdir.raku

#!/usr/bin/env raku
use v6.d;

sub MAIN($irgendwo = 'irgendwo') {
    # Hier ist genau '$*HOME'.
    my $tiefer = $*HOME.add: $irgendwo;
    chdir($tiefer) || die $tiefer ~ ': Es gibt nicht was Sie wollen.';
    say $*CWD;
}

./join.raku

#!/usr/bin/env raku
use v6.d;

sub MAIN(Str $inputText, Int $times) {
    my $outputList = $inputText xx $times.Int;
    my $outputText = $outputList.join: ',';
    say $outputText;
}

./deck.raku

#!/usr/bin/env raku
use v6.d;

sub MAIN() {
    say (< ♤ ♡ ♢ ♧ > X ( 2, 3, 4, 5, 6, 7, 8, 9, 10, 'jack', 'queen', 'king', 'ace' ));
}

./regex.raku ‘Name: Jane Doe, Age: 41, Email: john.doe@email.com END’

#!/usr/bin/env raku
use v6.d;

sub MAIN($input) {
    # Name: <John> <Doe>, Age: <25>, Email: <john.doe@email.com>
    say $input ~~ rx/"Name: "\w+\s\w+", Age: "\d+", Email: "<-[ \s ]>+/;
}

｢Name: Jane Doe, Age: 41, Email: john.doe@email.com｣

Bio

Q: I read your bio on Twitter. Do the emojis have something in common with Perl?

A: Indeed, those are a result of the following Raku program.

Indeed, those are a result of the following Raku program.

say "⬛" x 73 ~ (for 1..4 -> $i { "⚛" ~ "🍅" x $i }) ~ "👺" x 4;

⬛ ⬛ ⬛ ⬛ ⬛ ⬛ ⬛ ⬛ ⬛ ⬛ ⬛ ⬛ ⬛ ⬛ ⬛ ⬛ ⬛ ⬛ ⬛ ⬛ ⬛ ⬛ ⬛ ⬛ ⬛ ⬛ ⬛ ⬛ ⬛ ⬛ ⬛ ⬛ ⬛ ⬛ ⬛ ⬛ ⬛ ⬛ ⬛ ⬛ ⬛ ⬛ ⬛ ⬛ ⬛ ⬛ ⬛ ⬛ ⬛ ⬛ ⬛ ⬛ ⬛ ⬛ ⬛ ⬛ ⬛ ⬛ ⬛ ⬛ ⬛ ⬛ ⬛ ⬛ ⬛ ⬛ ⬛ ⬛ ⬛ ⬛ ⬛ ⬛ ⬛ ⚛ 🍅 ⚛ 🍅 🍅 ⚛ 🍅 🍅 🍅 ⚛ 🍅 🍅 🍅 🍅 👺 👺 👺 👺 Let’s examine all the parts. First, it prints a black square emoji 73 times. The black or graphite colour should resemble GitHub. The graphite colour encourages writing, and I do mean programming by that. 73 is 80% of 91, and the total number of emoji characters is 91. The widely known 80-20 rule, or the Pareto Principle, was applied. The second part contains a loop (for 1..4 -> $i { “⚛” ~ “🍅” x $i }). It produces a list of 4 atoms in 10 tomatoes. Note that the “tomato” word consists only of characters from the “atom” word. The idea is taken from a modern painting. Atom can mean atheism, and I read a lot about atheism. The last part 👺 is a Japanese goblin. Together with the atom emoji, it can represent atheism. It also means fourfaced, as one can be doublefaced, triplefaced, or even fourfaced. This idea was taken from a discussion about a modern painting. By not sticking to the constants, one can generate more bios. One last thing to do would be to remove the whitespaces. A shortened version of this bio is available on all my GitHub pages. ⬛⚛🍅👺 works usually as a footer but also as a header in the case of my GitHub profile. Let’s consider an alternative bio with a different arrangement ⚛⬛👺🍅. Atom would stand for atheism and black square for GitHub and programming. The Japanese goblin would represent my version of the Perl 1 compiler and OpenRoguelike. The tomato would represent an interest in compilers that is quite the traditional one. A further compiler worth knowing is Perl 5 and I want to read in German about it.

say "⚛" x 73 ~ (for 1..4 -> $i { "⬛" ~ "👺" x $i }) ~ "🍅" x 4;

⚛ ⚛ ⚛ ⚛ ⚛ ⚛ ⚛ ⚛ ⚛ ⚛ ⚛ ⚛ ⚛ ⚛ ⚛ ⚛ ⚛ ⚛ ⚛ ⚛ ⚛ ⚛ ⚛ ⚛ ⚛ ⚛ ⚛ ⚛ ⚛ ⚛ ⚛ ⚛ ⚛ ⚛ ⚛ ⚛ ⚛ ⚛ ⚛ ⚛ ⚛ ⚛ ⚛ ⚛ ⚛ ⚛ ⚛ ⚛ ⚛ ⚛ ⚛ ⚛ ⚛ ⚛ ⚛ ⚛ ⚛ ⚛ ⚛ ⚛ ⚛ ⚛ ⚛ ⚛ ⚛ ⚛ ⚛ ⚛ ⚛ ⚛ ⚛ ⚛ ⚛ ⬛👺 ⬛👺👺 ⬛👺👺👺 ⬛👺👺👺👺 🍅 🍅 🍅 🍅

⚛🍅🦅🦅