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<title>Raku (programming language)</title>

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Raku (programming language)

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</style><table class="infobox vevent"><tbody><tr><th colspan="2" class="infobox-above" style="background-color:#e0e0e0;">Raku</th></tr><tr><td colspan="2" class="infobox-image"><div class="infobox-caption">Camelia, the Raku mascot<a href="#cite_note-camelia-1">[1]</a></div></td></tr><tr><th scope="row" class="infobox-label"><a href="Programming_paradigm" title="Programming paradigm">Paradigm</a></th><td class="infobox-data"><a href="Multi-paradigm" class="mw-redirect" title="Multi-paradigm">Multi-paradigm</a></td></tr><tr><th scope="row" class="infobox-label">Family</th><td class="infobox-data"><a href="Perl" title="Perl">Perl</a></td></tr><tr><th scope="row" class="infobox-label"><a href="Software_design" title="Software design">Designed by</a></th><td class="infobox-data"><a href="Larry_Wall" title="Larry Wall">Larry Wall</a></td></tr><tr><th scope="row" class="infobox-label"><a href="Software_developer" class="mw-redirect" title="Software developer">Developer</a></th><td class="infobox-data organiser">Raku community</td></tr><tr><th scope="row" class="infobox-label">First appeared</th><td class="infobox-data">25 December 2015 (2015-12-25)</td></tr><tr><td colspan="2" class="infobox-full-data"></td></tr><tr><th scope="row" class="infobox-label" style="white-space: nowrap;"><a href="Software_release_life_cycle" title="Software release life cycle">Stable release</a></th><td class="infobox-data"><div style="margin:0px;">6.d 'Diwali'<a href="#cite_note-2">[2]</a>

/ 24 October 2020 (2020-10-24)</div></td></tr><tr style="display:none"><td colspan="2">

</td></tr><tr><th scope="row" class="infobox-label"><a href="Type_system" title="Type system">Typing discipline</a></th><td class="infobox-data"><a href="Dynamic_typing" class="mw-redirect" title="Dynamic typing">Dynamic</a>, <a href="Gradual_typing" title="Gradual typing">gradual</a></td></tr><tr><th scope="row" class="infobox-label"><a href="Operating_system" title="Operating system">OS</a></th><td class="infobox-data"><a href="Cross-platform" class="mw-redirect" title="Cross-platform">Cross-platform</a></td></tr><tr><th scope="row" class="infobox-label"><a href="Software_license" title="Software license">License</a></th><td class="infobox-data"><a href="GNU_General_Public_License" title="GNU General Public License">GNU General Public</a> or <a href="Artistic_License" title="Artistic License">Artistic 2</a></td></tr><tr><th scope="row" class="infobox-label"><a href="Filename_extension" title="Filename extension">Filename extensions</a></th><td class="infobox-data">.raku, .rakumod, .rakudoc, .rakutest, .nqp <a href="#cite_note-3">[3]</a></td></tr><tr><th scope="row" class="infobox-label">Website</th><td class="infobox-data"><a rel="nofollow" class="external text" href="https://raku.org/">raku.org</a></td></tr><tr><th colspan="2" class="infobox-header" style="background-color: #EEEEEE;">Major <a href="Programming_language_implementation" title="Programming language implementation">implementations</a></th></tr><tr><td colspan="2" class="infobox-full-data"><a href="Rakudo" title="Rakudo">Rakudo</a></td></tr><tr><th colspan="2" class="infobox-header" style="background-color: #EEEEEE;">Influenced by</th></tr><tr><td colspan="2" class="infobox-full-data"><a href="Perl" title="Perl">Perl</a>, <a href="Ruby_(programming_language)" title="Ruby (programming language)">Ruby</a>, <a href="Smalltalk" title="Smalltalk">Smalltalk</a>, <a href="Haskell" title="Haskell">Haskell</a>,<a href="#cite_note-4">[4]</a> <a href="JavaScript" title="JavaScript">JavaScript</a></td></tr><tr><th colspan="2" class="infobox-header" style="background-color: #EEEEEE;">Influenced</th></tr><tr><td colspan="2" class="infobox-full-data"><a href="Perl" title="Perl">Perl</a>,<a href="#cite_note-Tang2010-5">[5]</a> <a href="Haskell" title="Haskell">Haskell</a>,<a href="#cite_note-Tang2010-5">[5]</a> AntLang</td></tr></tbody></table>

Raku is a member of the <a href="Perl" title="Perl">Perl</a> family of <a href="Programming_language" title="Programming language">programming languages</a>.<a href="#cite_note-6">[6]</a> Formerly named Perl 6, it was renamed in October 2019.<a href="#cite_note-renamed-7">[7]</a><a href="#cite_note-8">[8]</a> Raku introduces elements of many modern and historical languages. Compatibility with Perl was not a goal, though a <a href="Compatibility_mode" title="Compatibility mode">compatibility mode</a> is part of the specification. The design process for Raku began in 2000.

<div class="mw-heading mw-heading2"><h2 id="History">History</h2></div>

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</style><blockquote class="templatequote">In Perl 6, we decided it would be better to fix the language than fix the user.</blockquote><div class="templatequotecite">— Larry Wall<a href="#cite_note-9">[9]</a></div>

The Raku design process was first announced on 19 July 2000, on the fourth day of that year's <a href="O'Reilly_Open_Source_Convention" title="O'Reilly Open Source Convention">Perl Conference</a>,<a href="#cite_note-10">[10]</a> by <a href="Larry_Wall" title="Larry Wall">Larry Wall</a> in his <a href="Perl#Community" title="Perl">State of the Onion</a> 2000 talk.<a href="#cite_note-11">[11]</a> At that time, the primary goals were to remove "historical warts" from the language; "easy things should stay easy, hard things should get easier, and impossible things should get hard"; and a general cleanup of the internal design and <a href="Application_programming_interface" class="mw-redirect" title="Application programming interface">application programming interfaces</a> (APIs). The process began with a series of <a href="Request_for_Comments" title="Request for Comments">Request for Comments</a> (RFCs). This process was open to all contributors, and left no aspect of the language closed to change.<a href="#cite_note-12">[12]</a>

Once the RFC process was complete, Wall reviewed and classified each of the 361 requests received. He then began the process of writing several "Apocalypses", using <a href="https://en.wiktionary.org/wiki/apocalypsis#English" class="extiw external" title="wikt:apocalypsis">the original meaning of the term</a>, "revealing".<a href="#cite_note-apoc1-13">[13]</a> While the original goal was to write one Apocalypse for each chapter of <a href="Programming_Perl" title="Programming Perl">Programming Perl</a>, it became obvious that, as each Apocalypse was written, previous Apocalypses were being invalidated by later changes. For this reason, a set of Synopses was published, each one relating the contents of an Apocalypse, but with any subsequent changes reflected in updates. Today, the Raku specification is managed through the "roast" testing suite,<a href="#cite_note-14">[14]</a> while the Synopses are kept as a historical reference.<a href="#cite_note-syn-15">[15]</a>

There is also a series of <a href="https://en.wiktionary.org/wiki/exegesis#English" class="extiw external" title="wikt:exegesis">Exegeses</a> written by <a href="Damian_Conway" title="Damian Conway">Damian Conway</a> that explain the content of each Apocalypse in terms of practical usage. Each Exegesis consists of code examples along with a discussion of the usage and implications of the examples.<a href="#cite_note-exegeses-16">[16]</a>

There are three primary methods of communication used in the development of Raku today. The first is the Raku <a href="Internet_Relay_Chat" class="mw-redirect" title="Internet Relay Chat">Internet Relay Chat</a> (IRC) channel on <a href="Libera_Chat" title="Libera Chat">Libera Chat</a>. The second is a set of <a href="Mailing_list" title="Mailing list">mailing lists</a>.<a href="#cite_note-lists-17">[17]</a> The third is the <a href="Git_(software)" class="mw-redirect" title="Git (software)">Git</a> <a href="Source_code_repository" class="mw-redirect" title="Source code repository">source code repository</a> hosted at <a href="GitHub" title="GitHub">GitHub</a>.<a href="#cite_note-18">[18]</a>

<div class="mw-heading mw-heading3"><h3 id="Initial_goals_and_implications">Initial goals and implications</h3></div>

The major goal Wall suggested in his initial speech was the removal of historical warts. These included the confusion surrounding <a href="Sigil_(computer_programming)" title="Sigil (computer programming)">sigil</a> usage for containers, the ambiguity between the <code>select</code> functions, and the syntactic impact of bareword <a href="Filehandle" class="mw-redirect" title="Filehandle">filehandles</a>. There were many other problems that Perl programmers had discussed fixing for years, and these were explicitly addressed by Wall in his speech.

An implication of these goals was that Perl 6 would not have <a href="Backward_compatibility" title="Backward compatibility">backward compatibility</a> with the existing Perl codebase. This meant that some code which was correctly interpreted by a Perl 5 compiler would not be accepted by a Perl 6 compiler. Since backward compatibility is a common goal when enhancing software, the breaking changes in Perl 6 had to be stated explicitly. The distinction between Perl 5 and Perl 6 became so large that eventually Perl 6 was renamed Raku.

<div class="mw-heading mw-heading3"><h3 id="Mascot">Mascot</h3></div>

The language's <a href="Mascot" title="Mascot">mascot</a> is "Camelia, the Raku bug".<a href="#cite_note-camelia-1">[1]</a>

Her name is a nod to the camel mascot associated with <a href="Perl" title="Perl">Perl</a>, and her form, in the pun-loving tradition of the Perl community, is a play on "<a href="Software_bug" title="Software bug">software bug</a>". Spiral designs embedded in her butterfly-like wings resemble the characters "P6", the favored nickname for Perl 6, and off-center eye placement is an intentional pun on "Wall-eyed".<a href="#cite_note-camelia-eyes-19">[19]</a>

One of the goals behind the lively and colorful design of the logo was to discourage misogyny in the community and for it to be an opportunity for those of "masculine persuasion" to show their sensitive side.<a href="#cite_note-camelia-purpose-20">[20]</a>

<div class="mw-heading mw-heading2"><h2 id="Implementations">Implementations</h2></div>

As of 2017, only the <a href="Rakudo" title="Rakudo">Rakudo</a> implementation is under active development. No implementation will be designated as the official Raku implementation; rather, "Raku is anything that passes the official test suite."<a href="#cite_note-21">[21]</a>

Rakudo Perl 6<a href="#cite_note-22">[22]</a><a href="#cite_note-23">[23]</a> targets a number of virtual machines, such as <a href="MoarVM" title="MoarVM">MoarVM</a>, the <a href="Java_virtual_machine" title="Java virtual machine">Java Virtual Machine</a>, and <a href="JavaScript" title="JavaScript">JavaScript</a>. MoarVM is a <a href="Virtual_machine" title="Virtual machine">virtual machine</a> built especially for Rakudo<a href="#cite_note-24">[24]</a> and the NQP Compiler Toolchain.<a href="#cite_note-25">[25]</a> There is a layer between Raku and the virtual machines named Not Quite Perl 6 (NQP), which implements <a href="Raku_rules" title="Raku rules">Raku rules</a> for parsing Raku, and an <a href="Abstract_syntax_tree" title="Abstract syntax tree">abstract syntax tree</a> and backend-specific <a href="Code_generation_(compiler)" title="Code generation (compiler)">code generation</a>. Large portions of Rakudo are written in Raku, or in its subset NQP. Rakudo is not a completely <a href="Self-hosting_(compilers)" title="Self-hosting (compilers)">self-hosting implementation</a>, nor are there concrete plans at this point to make Rakudo a <a href="Bootstrapping_(compilers)" title="Bootstrapping (compilers)">bootstrapping compiler</a>.

<div class="mw-heading mw-heading3"><h3 id="Historical_implementations">Historical implementations</h3></div>

<a href="Pugs_(compiler)" title="Pugs (compiler)">Pugs</a> was an initial implementation of Perl 6 written in <a href="Haskell" title="Haskell">Haskell</a>, led by <a href="Audrey_Tang" title="Audrey Tang">Audrey Tang</a>. Pugs used to be the most advanced implementation of Perl 6, but since mid 2007, it is mostly dormant (with updates made only to track the current version of the <a href="Glasgow_Haskell_Compiler" title="Glasgow Haskell Compiler">Glasgow Haskell Compiler</a> (GHC)). As of November 2014, Pugs was not being maintained.<a href="#cite_note-26">[26]</a>

In 2007, v6-MiniPerl6 ("mp6") and its reimplementation, v6-KindaPerl6 ("kp6") were written as a means to bootstrap the Perl-6.0.0 STD, using Perl 5. The STD is a full grammar for Perl 6 and is written in Perl 6. In theory, anything capable of parsing the STD and generating executable code is a suitable bootstrapping system for Perl 6. kp6 is currently compiled by mp6 and can work with multiple backends.<a href="#cite_note-STD-27">[27]</a><a href="#cite_note-28">[28]</a> mp6 and kp6 are not full Perl 6 implementations and are designed only to implement the minimum featureset required to bootstrap a full Perl 6 compiler.

Yapsi was a Perl 6 compiler and runtime written in Perl 6. As a result, it required an existing Perl 6 interpreter, such as one of the Rakudo Star releases, to run.<a href="#cite_note-29">[29]</a>

Niecza, another major Perl 6 implementation effort, focused on optimization and efficient implementation research. It targets the <a href="Common_Language_Infrastructure" title="Common Language Infrastructure">Common Language Infrastructure</a>.<a href="#cite_note-nieczareadme-30">[30]</a>

<div class="mw-heading mw-heading2"><h2 id="Module_system">Module system</h2></div>

The Raku specification requests that <a href="Perl_module" title="Perl module">modules</a> be identified by name, version, and authority.<a href="#cite_note-31">[31]</a> It is possible to load only a specific version of a module, or even two modules of the same name that differ in version or authority. As a convenience, <a href="Aliasing_(computing)" title="Aliasing (computing)">aliasing</a> to a short name is provided.

<a href="CPAN" title="CPAN">CPAN</a>, the Perl module distribution system, does not yet handle Raku modules. Instead a prototype module system is in use.<a href="#cite_note-32">[32]</a>

<div class="mw-heading mw-heading2"><h2 id="Major_changes_from_Perl">Major changes from Perl</h2></div>

Perl and Raku differ fundamentally, though in general the intent has been to "keep Raku Perl", so that Raku is clearly "a Perl programming language". Most of the changes are intended to normalize the language, to make it easier for novice and expert programmers alike to understand, and to make "easy things easier and hard things more possible".

<div class="mw-heading mw-heading3"><h3 id="A_specification">A specification</h3></div>

A major non-technical difference between Perl and Raku is that Raku began as a specification.<a href="#cite_note-syn01-33">[33]</a> This means that Raku can be re-implemented if needed, and it also means that programmers do not have to read the <a href="Source_code" title="Source code">source code</a> for the ultimate authority on any given feature. In contrast, in Perl, the official documentation is not considered authoritative and only describes the behavior of the actual Perl interpreter informally. Any discrepancies found between the documentation and the implementation may lead to either being changed to reflect the other, a dynamic which drives the continuing development and refinement of the Perl releases.

<div class="mw-heading mw-heading3"><h3 id="A_type_system">A type system</h3></div>

In Raku, the <a href="Dynamic_type" class="mw-redirect" title="Dynamic type">dynamic type system</a> of Perl has been augmented by the addition of <a href="Static_type" class="mw-redirect" title="Static type">static types</a>.<a href="#cite_note-syn2-34">[34]</a> For example:

<div class="mw-highlight mw-highlight-lang-raku mw-content-ltr" dir="ltr"><pre>my Int $i = 0;

my Rat $r = 3.142;

my Str $s = "Hello, world";

</pre></div>

However, static typing remains <a href="Type_system#Combining_static_and_dynamic_type_checking" title="Type system">optional</a>, so programmers can do most things without any explicit typing at all:

<div class="mw-highlight mw-highlight-lang-raku mw-content-ltr" dir="ltr"><pre>my $i = "25" + 10; # $i is 35

</pre></div>

Raku offers a <a href="Gradual_typing" title="Gradual typing">gradual typing</a> system, whereby the programmer may choose to use static typing, use dynamic typing, or mix the two.

<div class="mw-heading mw-heading3"><h3 id="Formal_subroutine_parameter_lists">Formal subroutine parameter lists</h3></div>

Perl defines subroutines without <a href="Parameter_(computer_science)" class="mw-redirect" title="Parameter (computer science)">formal parameter</a> lists at all (though simple parameter counting and some type checking can be done using Perl's "prototypes"). Subroutine arguments passed in are aliased into the elements of the array <code>@_</code>. If the elements of <code>@_</code> are modified, the changes are reflected in the original data.

Raku introduces true formal parameters to the language.<a href="#cite_note-syn6-35">[35]</a> In Raku, a subroutine declaration looks like this:

<div class="mw-highlight mw-highlight-lang-raku mw-content-ltr" dir="ltr"><pre>sub do_something(Str $thing, Int $other) {

...

}

</pre></div>

As in Perl, the formal parameters (i.e., the variables in the parameter list) are aliases to the actual parameters (the values passed in), but by default, the aliases are <a href="Constant_(programming)" class="mw-redirect" title="Constant (programming)">constant</a> so they cannot be modified. They may be declared explicitly as read-write aliases for the original value or as copies using the <code>is rw</code> or <code>is copy</code> directives respectively should the programmer require them to be modified locally.

<div class="mw-heading mw-heading4"><h4 id="Parameter_passing_modes">Parameter passing modes</h4></div>

Raku provides three basic modes of parameter passing: positional parameters, <a href="Named_parameter" title="Named parameter">named parameters</a>, and slurpy parameters.

Positional parameters are the typical ordered list of parameters that most programming languages use. All parameters may also be passed by using their name in an unordered way. Named-only parameters (indicated by a <code>:</code> before the parameter name) can only be passed by specifying its name, i.e. it never captures a positional argument. Slurpy parameters (indicated by an <code>*</code> before the parameter name) are Raku's tool for creating <a href="Variadic_function" title="Variadic function">variadic functions</a>. A slurpy hash will capture remaining passed-by-name parameters, whereas a slurpy array will capture remaining passed-by-position parameters.

Here is an example of the use of all three parameter-passing modes:

<div class="mw-highlight mw-highlight-lang-raku mw-content-ltr" dir="ltr"><pre>sub somefunction($a, $b, :$c, :$d, *@e) {

...

}

somefunction(1, 2, :d(3), 4, 5, 6); # $a=1, $b=2, $d=3, @e=(4,5,6)

</pre></div>

Positional parameters, such as those used above, are always required unless followed by <code>?</code> to indicate that they are optional. Named parameters are optional by default, but may be marked as required by adding <code>!</code> after the variable name. Slurpy parameters are always optional.

<div class="mw-heading mw-heading4"><h4 id="Blocks_and_closures">Blocks and closures</h4></div>

Parameters can also be passed to arbitrary blocks, which act as <a href="Closure_(computer_science)" class="mw-redirect" title="Closure (computer science)">closures</a>. This is how, for example, <code>for</code> and <code>while</code> loop iterators are named. In the following example, a list is traversed, 3 elements at a time, and passed to the loop's block as the variables, <code>$a, $b, $c</code>.<a href="#cite_note-syn04-36">[36]</a>

<div class="mw-highlight mw-highlight-lang-raku mw-content-ltr" dir="ltr"><pre>for @list -> $a, $b, $c {

...

}

</pre></div>

This is generally referred to as a "pointy sub" or "pointy block", and the arrow behaves almost exactly like the <code>sub</code> keyword, introducing an anonymous closure (or anonymous subroutine in Perl terminology).<a href="#cite_note-syn6-35">[35]</a>

<div class="mw-heading mw-heading3"><h3 id="Sigil_invariance">Sigil invariance</h3></div>

In Perl, <a href="Sigil_(computer_programming)" title="Sigil (computer programming)">sigils</a> – the punctuation characters that precede a variable name – change depending on how the variable is used:

<pre># Perl code

my @array = ('a', 'b', 'c');

my $element = $array[1]; # $element equals 'b',

my @extract = @array[1, 2]; # @extract equals ('b', 'c')

my $element = @array[1]; # 'b' comes with a warning (5.10 option)

</pre>

In Raku, sigils are invariant, which means that they do not change based on whether it is the array or the array element that is needed:<a href="#cite_note-syn2-34">[34]</a>

<pre># Raku code

my @array = 'a', 'b', 'c';

my $element = @array[1]; # $element equals 'b'

my @extract = @array[1, 2]; # @extract equals ('b', 'c')

my @extract = @array[1]; # @extract equals ('b')

</pre>

The variance in Perl is inspired by number agreement in English and many other natural languages:

<pre>"This apple." # $a CORRECT

"These apples." # @a CORRECT

"This third apple." # $a[3] CORRECT

"These third apple." # @a[3] WRONG

</pre>

However, this conceptual mapping breaks down when using <a href="Reference_(computer_science)" title="Reference (computer science)">references</a>, since they may refer to data structures even though they are scalars. Thus, dealing with nested data structures may require an expression of both singular and plural form in a single term:

<div class="mw-highlight mw-highlight-lang-perl mw-content-ltr" dir="ltr"><pre># Perl code: retrieve a list from the leaf of a hash containing hashes that contain arrays

my @trans_verbs = @{ $dictionary{ 'verb' }{ 'transitive' } };

</pre></div>

This complexity has no equivalent either in common use of natural language or in other programming languages, and it causes high <a href="Cognitive_load" title="Cognitive load">cognitive load</a> when writing code to manipulate complex data structures. This is the same code in Raku:

<div class="mw-highlight mw-highlight-lang-raku mw-content-ltr" dir="ltr"><pre># Raku code: retrieve a list from the leaf of a hash containing hashes that contain arrays

my @trans_verbs = %dictionary<verb><transitive><>;

</pre></div>

<div class="mw-heading mw-heading3"><h3 id="Object-oriented_programming">Object-oriented programming</h3></div>

Perl supports <a href="Object-oriented_programming" title="Object-oriented programming">object-oriented programming</a> via a mechanism known as blessing. Any reference can be blessed into being an object of a particular class. A blessed object can have <a href="Method_(computer_science)" class="mw-redirect" title="Method (computer science)">methods</a> invoked on it using the "arrow syntax" which will cause Perl to locate or "dispatch" an appropriate <a href="Subroutine" class="mw-redirect" title="Subroutine">subroutine</a> by name, and call it with the blessed variable as its first argument.

While extremely powerful, it makes the most common case of object orientation, a <a href="Struct" class="mw-redirect" title="Struct">struct</a>-like object with some associated code, unnecessarily difficult. In addition, because Perl can make no assumptions about the <a href="Object_model" title="Object model">object model</a> in use, method invocation cannot be optimized very well.

In the spirit of making the "easy things easy and hard things possible", Raku retains the blessing model and supplies a more robust object model for the common cases.<a href="#cite_note-37">[37]</a> For example, a class to encapsulate a <a href="Cartesian_coordinate_system" title="Cartesian coordinate system">Cartesian</a> <a href="Point_(geometry)" title="Point (geometry)">point</a> could be defined and used this way:

<div class="mw-highlight mw-highlight-lang-raku mw-content-ltr" dir="ltr"><pre>class Point is rw {

has $.x;

has $.y;

method distance( Point $p ) {

sqrt(($!x - $p.x) ** 2 + ($!y - $p.y) ** 2)

}

method distance-to-center {

self.distance: Point.new(x => 0, y => 0)

}

my $point = Point.new( x => 1.2, y => -3.7 );

say "Point's location: (", $point.x, ', ', $point.y, ')';

# OUTPUT: Point's location: (1.2, -3.7)

# Changing x and y (note methods "x" and "y" used as lvalues):

$point.x = 3;

$point.y = 4;

# OUTPUT: Point's location: (3, 4)

my $other-point = Point.new(x => -5, y => 10);

$point.distance($other-point); #=> 10

$point.distance-to-center; #=> 5

</pre></div>

The dot replaces the arrow in a nod to the many other languages (e.g. <a href="C%2B%2B" title="C++">C++</a>, <a href="Java_(programming_language)" title="Java (programming language)">Java</a>, <a href="Python_(programming_language)" title="Python (programming language)">Python</a>, etc.) that have coalesced around dot as the syntax for method invocation.

In the terminology of Raku, <code>$.x</code> is called an "attribute". Some languages call these fields or members. The method used to access an attribute is called an "accessor". An auto-accessor method is a method created automatically and named after the attribute's name, as the method <code>x</code> is in the example above. These accessor functions return the value of the attribute. When a class or individual attribute is declared with the <code>is rw</code> modifier (short for "read/write"), the auto-accessors can be passed a new value to set the attribute to, or it can be directly assigned to as an <a href="Value_(computer_science)#lrvalue" title="Value (computer science)">lvalue</a> (as in the example). Auto-accessors can be replaced by user-defined methods, should the programmer desire a richer interface to an attribute. Attributes can only be accessed directly from within a class definition via the <code>$!</code> syntax regardless of how the attributes are declared. All other access must go through the accessor methods.

The Raku object system has inspired the <a href="Moose_(Perl)" title="Moose (Perl)">Moose</a> framework that introduces many of Raku's OOP features to Perl.

<div class="mw-heading mw-heading4"><h4 id="Inheritance,_Roles_and_Classes">Inheritance, Roles and Classes</h4></div>

Inheritance is the technique by which an object or type can re-use code or definitions from existing objects or types. For example, a programmer may want to have a standard type but with an extra attribute. Inheritance in other languages, such as Java, is provided by allowing Classes to be sub-classes of existing classes.

Raku provides for inheritance via Classes, which are similar to Classes in other languages, and Roles.

Roles in Raku take on the function of <a href="Interface_(Java)" title="Interface (Java)">interfaces in Java</a>, <a href="Mixin" title="Mixin">mixins</a> in Ruby, and <a href="Trait_(computer_science)" class="mw-redirect" title="Trait (computer science)">traits</a><a href="#cite_note-38">[38]</a> in <a href="PHP" title="PHP">PHP</a> and in the <a href="Smalltalk" title="Smalltalk">Smalltalk</a> variant <a href="Squeak" title="Squeak">Squeak</a>. These are much like classes, but they provide a safer composition mechanism.<a href="#cite_note-39">[39]</a> These are used to perform composition when used with classes rather than adding to their <a href="Inheritance_(object-oriented_programming)" title="Inheritance (object-oriented programming)">inheritance</a> chain. Roles define nominal types; they provide semantic names for collections of behavior and state. The fundamental difference between a role and a class is that classes can be instantiated; roles are not.<a href="#cite_note-40">[40]</a>

Although Roles are distinct from Classes, it is possible to write Raku code that directly instantiates a Role or uses a Role as a type object, Raku will automatically create a class with the same name as the role, making it possible to transparently use a role as if it were a class.<a href="#cite_note-41">[41]</a>

Essentially, a role is a bundle of (possibly abstract) methods and attributes that can be added to a class without using inheritance. A role can even be added to an individual object; in this case, Raku will create an anonymous subclass, add the role to the subclass, and change the object's class to the anonymous subclass.

For example, a <a href="Dog" title="Dog">Dog</a> is a <a href="Mammal" title="Mammal">Mammal</a> because dogs inherit certain characteristics from Mammals, such as <a href="Mammary_gland" title="Mammary gland">mammary glands</a> and (through Mammal's parent, <a href="Vertebrate" title="Vertebrate">Vertebrate</a>) a <a href="Vertebral_column" class="mw-redirect" title="Vertebral column">backbone</a>. On the other hand, dogs also may have one of several distinct types of behavior, and these behaviours may change over time. For example, a Dog may be a <a href="Pet" title="Pet">Pet</a>, a <a href="Feral" title="Feral">Stray</a> (an abandoned pet will acquire behaviours to survive not associated with a pet), or a <a href="Guide_dog" title="Guide dog">Guide</a> for the blind (guide dogs are trained, so they do not start life as guide dogs). However, these are sets of additional behaviors that can be added to a Dog. It is also possible to describe these behaviors in such a way that they can be usefully applied to other animals, for example, a <a href="Cat" title="Cat">Cat</a> can equally be a Pet or Stray. Hence, Dog and Cat are distinct from each other, while both remain within the more general category Mammal. So Mammal is a Class and Dog and Cat are classes that inherit from Mammal. But the behaviours associated with Pet, Stray, and Guide are Roles that can be added to Classes, or objects instantiated from Classes.

<div class="mw-highlight mw-highlight-lang-raku mw-content-ltr" dir="ltr"><pre>class Mammal is Vertebrate {

...

}

class Dog is Mammal {

...

}

role Pet {

...

}

role Stray {

...

}

role Guide {

...

}

</pre></div>

Roles are added to a class or object with the <code>does</code> keyword. In order to show inheritance from a class, there is a different keyword <code>is</code>. The keywords reflect the differing meanings of the two features: role composition gives a class the behavior of the role, but doesn't indicate that it is truly the same thing as the role.

<div class="mw-highlight mw-highlight-lang-raku mw-content-ltr" dir="ltr"><pre>class GuideDog is Dog does Guide {

...

} # Subclass composes role

my $dog = new Dog;

$dog does Guide; # Individual object composes role

</pre></div>

Although roles are distinct from classes, both are types, so a role can appear in a variable declaration where one would normally put a class. For example, a Blind role for a Human could include an attribute of type Guide; this attribute could contain a Guide Dog, a <a href="Guide_horse" title="Guide horse">Guide Horse</a>, a Guide Human, or even a Guide Machine.

<div class="mw-highlight mw-highlight-lang-raku mw-content-ltr" dir="ltr"><pre>class Human {

has Dog $dog; # Can contain any kind of Dog, whether it does the

... # Guide role or not

}

role Blind {

has Guide $guide; # Can contain any object that does the Guide role,

... # whether it is a Dog or something else

}

</pre></div>

<div class="mw-heading mw-heading3"><h3 id="Regular_expressions">Regular expressions</h3></div>

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</style><div role="note" class="hatnote navigation-not-searchable">Main article: <a href="Raku_rules" title="Raku rules">Raku rules</a></div>

Perl's <a href="Regular_expression" title="Regular expression">regular expression</a> and string-processing support has always been one of its defining features.<a href="#cite_note-42">[42]</a> Since Perl's pattern-matching constructs have exceeded the capabilities of <a href="Regular_language" title="Regular language">regular language</a> expressions for some time,<a href="#cite_note-43">[43]</a> Raku documentation exclusively refers to them as regexes, distancing the term from the formal definition.

Raku provides a superset of Perl features with respect to regexes, folding them into a larger framework called "<a href="Raku_rules" title="Raku rules">rules</a>" which provide the capabilities of <a href="Context-sensitive_language" title="Context-sensitive language">context-sensitive</a> <a href="Parsing" title="Parsing">parsing</a> formalisms (such as the <a href="Syntactic_predicate" title="Syntactic predicate">syntactic predicates</a> of <a href="Parsing_expression_grammar" title="Parsing expression grammar">parsing expression grammars</a> and <a href="ANTLR" title="ANTLR">ANTLR</a>), as well as acting as a <a href="Closure_(computer_science)" class="mw-redirect" title="Closure (computer science)">closure</a> with respect to their <a href="Scope_(programming)" class="mw-redirect" title="Scope (programming)">lexical scope</a>.<a href="#cite_note-44">[44]</a> Rules are introduced with the <code>rule</code> keyword which has a usage quite similar to subroutine definition. Anonymous rules can also be introduced with the <code>regex</code> (or <code>rx</code>) keyword, or they can simply be used inline as regexps were in Perl via the <code>m</code> (matching) or <code>s</code> (substitute) operators.

In Apocalypse 5, Larry Wall enumerated 20 problems with "current regex culture". Among these were that Perl's regexes were "too compact and 'cute'", had "too much reliance on too few metacharacters", "little support for named captures", "little support for grammars", and "poor integration with 'real' language".<a href="#cite_note-45">[45]</a>

<div class="mw-heading mw-heading3"><h3 id="Syntactic_simplification">Syntactic simplification</h3></div>

Some Perl constructs have been changed in Raku, optimized for different syntactic cues for the most common cases. For example, the parentheses (round <a href="Bracket" title="Bracket">brackets</a>) required in <a href="Control_flow" title="Control flow">control flow</a> constructs in Perl are now optional:<a href="#cite_note-syn04-36">[36]</a>

<div class="mw-highlight mw-highlight-lang-raku mw-content-ltr" dir="ltr"><pre>if is-true() {

for @array {

...

}

</pre></div>

Also, the <code>,</code> (comma) operator is now a list constructor, so enclosing parentheses are no longer required around lists. The code

<div class="mw-highlight mw-highlight-lang-raku mw-content-ltr" dir="ltr"><pre>@array = 1, 2, 3, 4;

</pre></div>

now makes <code>@array</code> an array with exactly the elements '1', '2', '3', and '4'.

<div class="mw-heading mw-heading3"><h3 id="Chained_comparisons">Chained comparisons</h3></div>

Raku allows comparisons to "chain". That is, a sequence of comparisons such as the following is allowed:

<div class="mw-highlight mw-highlight-lang-raku mw-content-ltr" dir="ltr"><pre>if 20 <= $temperature <= 25 {

say "Room temperature is between 20 and 25!"

}

</pre></div>

This is treated as if each left-to-right comparison were performed on its own, and the result is logically combined via the <code>and</code> operation.

<div class="mw-heading mw-heading3"><h3 id="Lazy_evaluation">Lazy evaluation</h3></div>

Raku uses the technique of <a href="Lazy_evaluation" title="Lazy evaluation">lazy evaluation</a> of lists that has been a feature of some <a href="Functional_programming" title="Functional programming">functional programming</a> languages such as <a href="Haskell_(programming_language)" class="mw-redirect" title="Haskell (programming language)">Haskell</a>:<a href="#cite_note-syn9-46">[46]</a>

<div class="mw-highlight mw-highlight-lang-raku mw-content-ltr" dir="ltr"><pre>@integers = 0..Inf; # integers from 0 to infinity

</pre></div>

The code above will not crash by attempting to assign a list of infinite size to the array <code>@integers</code>, nor will it hang indefinitely in attempting to expand the list if a limited number of slots are searched.

This simplifies many common tasks in Raku including input/output operations, list transformations, and parameter passing.

<div class="mw-heading mw-heading3"><h3 id="Gather">Gather</h3></div>

Related to lazy evaluation is the construction of lazy lists using <code>gather</code> and <code>take</code>, behaving somewhat like generators in languages like <a href="Icon_(programming_language)" title="Icon (programming language)">Icon</a> or <a href="Python_(programming_language)" title="Python (programming language)">Python</a>.

<div class="mw-highlight mw-highlight-lang-raku mw-content-ltr" dir="ltr"><pre>my $squares = lazy gather for 0..Inf {

take $_ * $_;

};

</pre></div>

<code>$squares</code> will be an infinite list of square numbers, but lazy evaluation of the <code>gather</code> ensures that elements are only computed when they are accessed.

<div class="mw-heading mw-heading3"><h3 id="Junctions">Junctions</h3></div>

Raku introduces the concept of junctions: values that are composites of other values.<a href="#cite_note-syn9-46">[46]</a> In their simplest form, junctions are created by combining a set of values with junctive <a href="Operator_(programming)" class="mw-redirect" title="Operator (programming)">operators</a>:

<div class="mw-highlight mw-highlight-lang-raku mw-content-ltr" dir="ltr"><pre># Example for | ("any") Junction:

my $color = 'white';

unless $color eq 'white' | 'black' | 'gray' | 'grey' {

die "Color printing not supported\n";

}

# Example for & ("all") Junction:

my $password = 'secret!123';

if $password ~~ /<:alpha>/ & /<:digit>/ & /<:punct>/ {

say "Your password is reasonably secure";

}

</pre></div>

<code>|</code> indicates a value which is equal to either its left- or right-hand arguments. <code>&</code> indicates a value which is equal to both its left- and right-hand arguments. These values can be used in any code that would use a normal value. Operations performed on a junction act on all members of the junction equally, and combine according to the junctive operator. So, <code>("apple"|"banana") ~ "s"</code> would yield <code>"apples"|"bananas"</code>. In comparisons, junctions return a single true or false result for the comparison. "<code>any</code>" junctions return true if the comparison is true for any one of the elements of the junction. "<code>all</code>" junctions return true if the comparison is true for all of the elements of the junction.

Junctions can also be used to more richly augment the type system by introducing a style of <a href="Generic_programming" title="Generic programming">generic programming</a> that is constrained to junctions of types:

<div class="mw-highlight mw-highlight-lang-raku mw-content-ltr" dir="ltr"><pre>subset Color of Any where RGB_Color | CMYK_Color;

sub get_tint(Color $color, Num $opacity) {

...

}

</pre></div>

<div class="mw-heading mw-heading3"><h3 id="Macros">Macros</h3></div>

In low-level languages, the concept of <a href="Macro_(computer_science)" title="Macro (computer science)">macros</a> has become synonymous with textual substitution of source-code due to the widespread use of the <a href="C_preprocessor" title="C preprocessor">C preprocessor</a>. However, high-level languages such as <a href="Lisp_programming_language" class="mw-redirect" title="Lisp programming language">Lisp</a> pre-dated C in their use of macros that were far more powerful.<a href="#cite_note-47">[47]</a> It is this Lisp-like macro concept that Raku will take advantage of.<a href="#cite_note-syn6-35">[35]</a> The power of this sort of macro stems from the fact that it operates on the program as a high-level <a href="Data_structure" title="Data structure">data structure</a>, rather than as simple text, and has the full capabilities of the programming language at its disposal.

A Raku macro definition will look like a subroutine or method definition, and it can operate on unparsed strings, an <a href="Abstract_syntax_tree" title="Abstract syntax tree">AST</a> representing pre-parsed code, or a combination of the two. A macro definition would look like this:<a href="#cite_note-macros-48">[48]</a>

<div class="mw-highlight mw-highlight-lang-raku mw-content-ltr" dir="ltr"><pre>macro hello($what) {

quasi { say "Hello { {{{$what}}} }" };

}

</pre></div>

In this particular example, the macro is no more complex than a C-style textual substitution, but because parsing of the macro parameter occurs before the macro operates on the calling code, diagnostic messages would be far more informative. However, because the body of a macro is executed at <a href="Compile_time" title="Compile time">compile time</a> each time it is used, many techniques of <a href="Optimization_(computer_science)" class="mw-redirect" title="Optimization (computer science)">optimization</a> can be employed. It is even possible to eliminate complex computations from resulting programs by performing the work at compile-time.

<div class="mw-heading mw-heading3"><h3 id="Identifiers">Identifiers</h3></div>

In Perl, identifier names can use the ASCII alphanumerics and underscores also available in other languages. In Raku, the alphanumerics can include most Unicode characters. In addition, hyphens and apostrophes can be used (with certain restrictions, such as not being followed by a digit). Using hyphens instead of underscores to separate words in a name leads to a style of naming called "<a href="Kebab_case" class="mw-redirect" title="Kebab case">kebab case</a>".

<div class="mw-heading mw-heading2"><h2 id="Examples">Examples</h2></div>

<div class="mw-heading mw-heading3"><h3 id="Hello_world">Hello world</h3></div>

The <a href="Hello_world_program" class="mw-redirect" title="Hello world program">hello world program</a> is a common program used to introduce a language. In Raku, hello world is:

<div class="mw-highlight mw-highlight-lang-raku mw-content-ltr" dir="ltr"><pre>say 'Hello, world';

</pre></div>

— though <a href="There_is_more_than_one_way_to_do_it" class="mw-redirect" title="There is more than one way to do it">there is more than one way to do it</a>.

<div class="mw-heading mw-heading3"><h3 id="Factorial">Factorial</h3></div>

The <a href="Factorial" title="Factorial">factorial</a> function in Raku, defined in a few different ways:

<div class="mw-highlight mw-highlight-lang-raku mw-content-ltr" dir="ltr"><pre># Using recursion (with `if\else` construct)

sub fact( UInt $n --> UInt ) {

if $n == 0 { 1 }

else { $n * fact($n-1) }

}

# Using recursion (with `if` as statement modifier)

sub fact( UInt $n --> UInt ) {

return 1 if $n == 0;

return $n * fact($n-1);

}

# Using recursion (with `when` construct)

sub fact( UInt $n --> UInt ) {

when $n == 0 { 1 }

default { $n * fact($n-1) }

}

# Using the ternary operator

sub fact( UInt $n --> UInt ) {

$n == 0 ?? 1 !! $n * fact($n-1)

}

# Using multiple dispatch

multi fact(0) { 1 }

multi fact( UInt $n --> UInt ) {

$n * fact($n - 1)

}

# Using the reduction metaoperator

sub fact( UInt $n --> UInt ) {

[*] 1..$n

}

# Creating a factorial operator and using the reduction metaoperator

sub postfix:<!>( UInt $n --> UInt ) { [*] 1..$n }

# Using `state` declarator to create a memoized factorial

sub fact( UInt $n --> UInt ) {

state %known = 0 => 1;

return %known{$n} if %known{$n}:exists;

%known{$n} = $n * fact($n-1);

return %known{$n};

}

</pre></div>

<div class="mw-heading mw-heading3"><h3 id="Quicksort">Quicksort</h3></div>

<a href="Quicksort" title="Quicksort">Quicksort</a> is a well-known sorting algorithm. A working implementation<a href="#cite_note-49">[a]</a> using the functional programming paradigm can be succinctly written in Raku:

<div class="mw-highlight mw-highlight-lang-raku mw-content-ltr" dir="ltr"><pre># Empty list sorts to the empty list

multi quicksort([]) { () }

# Otherwise, extract first item as pivot...

multi quicksort([$pivot, *@rest]) {

# Partition.

my @before = @rest.grep(* < $pivot);

my @after = @rest.grep(* >= $pivot);

# Sort the partitions.

flat (quicksort(@before), $pivot, quicksort(@after))

}

</pre></div>

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<li id="cite_note-49"><a href="#cite_ref-49">^</a> Unless the implementation does something fancy and mysterious behind the scenes, the maximal possible recursion depth is the length of the list, making this implementation unsuitable for big data. Recursion depth can be limited to <code>log2(list_length)</code> by iterating into the larger of partitions <code>before</code> and <code>after</code>, and only recursing into the smaller partition.

</li>

</ol></div></div>

<div class="mw-heading mw-heading3"><h3 id="Tower_of_Hanoi">Tower of Hanoi</h3></div>

<a href="Tower_of_Hanoi" title="Tower of Hanoi">Tower of Hanoi</a> is often used to introduce recursive programming in computer science. This implementation uses Raku's multi-dispatch mechanism and parametric constraints:

<div class="mw-highlight mw-highlight-lang-raku mw-content-ltr" dir="ltr"><pre>multi sub hanoi(0, $, $, $) { } # No disk, so do not do anything

multi sub hanoi($n, $a = 'A', $b = 'B', $c = 'C') { # Start with $n disks and three pegs A, B, C

hanoi $n - 1, $a, $c, $b; # firstly move top $n - 1 disks from A to B

say "Move disk $n from peg $a to peg $c"; # then move last disk from A to C

hanoi $n - 1, $b, $a, $c; # lastly move $n - 1 disks from B to C

}

</pre></div>

<div class="mw-heading mw-heading2"><h2 id="Books">Books</h2></div>

In the history of Raku there were two waves of book writing. The first wave followed the initial announcement of Perl 6 in 2000. Those books reflect the state of the design of the language of that time, and contain mostly outdated material. The second wave, that followed the announcement of Version 1.0 in 2015, includes several books that have already been published and some others that are in the process of being written.

<div class="mw-heading mw-heading3"><h3 id="Books_published_before_Perl_6_version_1.0_(known_as_version_6.c)">Books published before Perl 6 version 1.0 (known as version 6.c)</h3></div>

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</style><cite id="CITEREFRandalSugalskiTötsch2003" class="citation book cs1">Randal, Allison; Sugalski, Dan; Tötsch, Leopold (2003). Perl 6 Essentials (1st ed.). O'Reilly Media. <a href="ISBN_(identifier)" class="mw-redirect" title="ISBN (identifier)">ISBN</a> <bdi>978-0-596-00499-6</bdi>.</cite></li>

<li><cite id="CITEREFRandalSugalskiTötsch2004" class="citation book cs1">Randal, Allison; Sugalski, Dan; Tötsch, Leopold (2004). <a rel="nofollow" class="external text" href="http://shop.oreilly.com/product/9780596007379.do">Perl 6 and Parrot Essentials</a> (2nd ed.). O'Reilly Media. <a href="ISBN_(identifier)" class="mw-redirect" title="ISBN (identifier)">ISBN</a> <bdi>978-0-596-00737-9</bdi>.</cite></li>

<li><cite id="CITEREFWalters2004" class="citation book cs1">Walters, Scott (15 December 2004). <a rel="nofollow" class="external text" href="http://www.apress.com/us/book/9781590593950">Perl 6 Now: The Core Ideas Illustrated with Perl 5</a>. Expert's Voice in Open Source. <a href="ISBN_(identifier)" class="mw-redirect" title="ISBN (identifier)">ISBN</a> <bdi>978-1-59059-395-0</bdi>.</cite></li></ul>

Also, a book dedicated to one of the first Perl 6 virtual machines, Parrot, was published in 2009.

<ul><li><cite id="CITEREFRandalWhitworth2009" class="citation book cs1">Randal, Allison; Whitworth, Andrew (15 June 2009). <a rel="nofollow" class="external text" href="https://web.archive.org/web/20161018020706/http://www.onyxneon.com/books/pir/index.html">Parrot Developer's Guide: Pir</a>. Onyx Neon Press. <a href="ISBN_(identifier)" class="mw-redirect" title="ISBN (identifier)">ISBN</a> <bdi>978-0-9779201-2-9</bdi>. Archived from <a rel="nofollow" class="external text" href="http://onyxneon.com/books/pir/index.html">the original</a> on 18 October 2016. Retrieved 24 July 2017.</cite></li></ul>

<div class="mw-heading mw-heading3"><h3 id="Books_published_after_Perl_6_version_1.0_(known_as_version_6.c)">Books published after Perl 6 version 1.0 (known as version 6.c)</h3></div>

<ul><li><cite id="CITEREFShitov2017" class="citation book cs1">Shitov, Andrew (2017). <a rel="nofollow" class="external text" href="https://andrewshitov.com/perl6-at-a-glance/">Perl 6 at a Glance</a>. Amazon Digital Services LLC - Kdp. <a href="ISBN_(identifier)" class="mw-redirect" title="ISBN (identifier)">ISBN</a> <bdi>978-90-821568-3-6</bdi>.</cite></li>

<li><cite id="CITEREFRosenfeldDowney2017" class="citation book cs1">Rosenfeld, Laurent; Downey, Allen B. (2017). <a rel="nofollow" class="external text" href="http://shop.oreilly.com/product/0636920065883.do">Think Perl 6</a>. O'Reilly Media. <a href="ISBN_(identifier)" class="mw-redirect" title="ISBN (identifier)">ISBN</a> <bdi>978-1-4919-8055-2</bdi>.</cite></li>

<li><cite id="CITEREFMerelo2017" class="citation book cs1">Merelo, J. J. (9 July 2017). <a rel="nofollow" class="external text" href="https://github.com/JJ/perl6em/tree/master/docs">Learning to program with Perl 6: First Steps: Getting into programming without leaving the command line</a>. Learning to Program with Perl. <a href="ISBN_(identifier)" class="mw-redirect" title="ISBN (identifier)">ISBN</a> <bdi>978-1-5217-9578-1</bdi>.</cite></li>

<li><cite id="CITEREFLenz2017" class="citation book cs1">Lenz, Moritz (27 July 2017). <a rel="nofollow" class="external text" href="https://www.apress.com/us/book/9781484228982">Perl 6 Fundamentals</a>. Apress. <a href="ISBN_(identifier)" class="mw-redirect" title="ISBN (identifier)">ISBN</a> <bdi>978-1-4842-2898-2</bdi>.</cite></li>

<li><cite id="CITEREFShitov2017" class="citation book cs1">Shitov, Andrew (7 September 2017). <a rel="nofollow" class="external text" href="https://www.packtpub.com/application-development/perl-6-deep-dive">Perl 6 Deep Dive</a>. Packt Publishing, Limited. <a href="ISBN_(identifier)" class="mw-redirect" title="ISBN (identifier)">ISBN</a> <bdi>978-1-78728-204-9</bdi>.</cite></li>

<li><cite id="CITEREFShitov2017" class="citation book cs1">Shitov, Andrew (2017). <a rel="nofollow" class="external text" href="https://andrewshitov.com/using-perl6/">Using Perl 6</a>. <a href="ISBN_(identifier)" class="mw-redirect" title="ISBN (identifier)">ISBN</a> <bdi>978-90-821568-1-2</bdi>.</cite></li>

<li><cite id="CITEREFSzabo2017" class="citation book cs1">Szabo, Gabor (3 December 2017). <a rel="nofollow" class="external text" href="https://leanpub.com/bailador">Web Application Development in Perl 6</a>. Author.</cite></li>

<li><cite id="CITEREFLenz2017" class="citation book cs1">Lenz, Moritz (4 December 2017). <a rel="nofollow" class="external text" href="https://www.apress.com/us/book/9781484232279">Parsing with Perl 6 Regexes and Grammars: A Recursive Descent into Parsing</a>. Apress. <a href="ISBN_(identifier)" class="mw-redirect" title="ISBN (identifier)">ISBN</a> <bdi>978-1-4842-3228-6</bdi>.</cite></li>

<li><cite id="CITEREFFoy2018" class="citation book cs1">Foy, Brian D. (2018). <a rel="nofollow" class="external text" href="http://shop.oreilly.com/product/0636920062776.do">Learning Perl 6</a>. O'Reilly Media. <a href="ISBN_(identifier)" class="mw-redirect" title="ISBN (identifier)">ISBN</a> <bdi>978-1-4919-7768-2</bdi>.</cite></li></ul>

<div class="mw-heading mw-heading3"><h3 id="Books_published_with_the_new_Raku_name">Books published with the new Raku name</h3></div>

<ul><li><cite id="CITEREFShitov2019" class="citation book cs1">Shitov, Andrew (13 October 2019). <a rel="nofollow" class="external text" href="https://andrewshitov.com/2019/10/13/using-raku-the-free-book/">Using Raku: 100 Programming Challenges Solved in the Raku Programming Language</a> (2nd ed.). Suzi K Edwards. <a href="ISBN_(identifier)" class="mw-redirect" title="ISBN (identifier)">ISBN</a> <bdi>978-90-821568-8-1</bdi>.</cite></li>

<li><cite id="CITEREFShitov2019" class="citation book cs1">Shitov, Andrew (18 October 2019). <a rel="nofollow" class="external text" href="https://andrewshitov.com/2019/10/18/raku-one-liners-a-free-book/">Raku One-Liners: Getting the Most of Raku's Expressive Syntax for Your Daily Routines</a>. Amazon Digital Services LLC - Kdp. <a href="ISBN_(identifier)" class="mw-redirect" title="ISBN (identifier)">ISBN</a> <bdi>978-90-821568-9-8</bdi>.</cite></li>

<li><cite id="CITEREFLenz2020" class="citation book cs1">Lenz, Moritz (6 September 2020). <a rel="nofollow" class="external text" href="https://link.springer.com/book/10.1007/978-1-4842-6109-5">Raku Fundamentals: A Primer with Examples, Projects, and Case Studies</a>. Apress. <a href="Doi_(identifier)" class="mw-redirect" title="Doi (identifier)">doi</a>:<a rel="nofollow" class="external text" href="https://doi.org/10.1007%2F978-1-4842-6109-5">10.1007/978-1-4842-6109-5</a>. <a href="ISBN_(identifier)" class="mw-redirect" title="ISBN (identifier)">ISBN</a> <bdi>978-1-4842-6108-8</bdi>.</cite></li></ul>

<div class="mw-heading mw-heading2"><h2 id="References">References</h2></div>

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<li id="cite_note-45"><a href="#cite_ref-45">^</a> <cite id="CITEREFWall,_Larry2002" class="citation web cs1">Wall, Larry (4 June 2002). <a rel="nofollow" class="external text" href="https://web.archive.org/web/20210822004436/https://raku.org/archive/doc/design/apo/A05.html">"Apocalypse 5: Pattern Matching"</a>. Archived from <a rel="nofollow" class="external text" href="https://raku.org/archive/doc/design/apo/A05.html">the original</a> on 22 August 2021. Retrieved 16 May 2020.</cite>

</li>

<li id="cite_note-syn9-46">^ <a href="#cite_ref-syn9_46-0">a</a> <a href="#cite_ref-syn9_46-1">b</a> <cite id="CITEREFWall,_Larry2004" class="citation web cs1">Wall, Larry (13 September 2004). <a rel="nofollow" class="external text" href="https://design.raku.org/S09.html">"Synopsis 9: Data Structures"</a>.</cite>

</li>

<li id="cite_note-47"><a href="#cite_ref-47">^</a> <cite id="CITEREFLamkins,_David_B.2004" class="citation book cs1">Lamkins, David B. (8 December 2004). <a rel="nofollow" class="external text" href="https://web.archive.org/web/20060912113327/http://www.psg.com/~dlamkins/sl/chapter20.html">Successful Lisp: How to Understand and Use Common Lisp</a>. bookfix.com. Archived from <a rel="nofollow" class="external text" href="http://psg.com/~dlamkins/sl/chapter20.html">the original</a> on 12 September 2006. Retrieved 13 September 2006.</cite>

</li>

<li id="cite_note-macros-48"><a href="#cite_ref-macros_48-0">^</a> <cite class="citation web cs1"><a rel="nofollow" class="external text" href="https://github.com/Raku/old-design-docs">"Raku/old-design-docs"</a>. 10 September 2024 – via GitHub.</cite>

</li>

</ol></div></div>

<div class="mw-heading mw-heading2"><h2 id="External_links">External links</h2></div>

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<div class="side-box-text plainlist">Wikibooks has a book on the topic of: <a href="https://en.wikibooks.org/wiki/Perl_6_Programming" class="extiw external" title="wikibooks:Perl 6 Programming">Perl 6 Programming</a></div></div>

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<ul><li><a rel="nofollow" class="external text" href="https://raku.org/">Official website</a> </li></ul>

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</style><div id="Perl142" style="font-size:114%;margin:0 4em"><a href="Perl" title="Perl">Perl</a></div></th></tr><tr><th scope="row" class="navbox-group" style="width:1%">Things</th><td class="navbox-list-with-group navbox-list navbox-odd" style="width:100%;padding:0"><div style="padding:0 0.25em">

<li><a href="Perl_Foundation" title="Perl Foundation">Perl Foundation</a>

<ul><li><a href="Perl_Mongers" title="Perl Mongers">Perl Mongers</a></li>

<li><a href="PerlMonks" title="PerlMonks">PerlMonks</a></li>

<li><a href="CPAN" title="CPAN">archives</a></li></ul></li>

<li><a href="Perl_module" title="Perl module">module</a></li>

</div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%"><a href="Software_framework" title="Software framework">Frameworks</a></th><td class="navbox-list-with-group navbox-list navbox-even" style="width:100%;padding:0"><div style="padding:0 0.25em">

<ul><li><a href="BioPerl" title="BioPerl">BioPerl</a></li>

<li><a href="Catalyst_(software)" title="Catalyst (software)">Catalyst</a></li>

<li><a href="Dancer_(software)" title="Dancer (software)">Dancer</a></li>

<li><a href="DBIx%3A%3AClass" title="DBIx::Class">DBIx::Class</a></li>

<li><a href="Mojolicious" title="Mojolicious">Mojolicious</a></li>

<li><a href="Moose_(Perl)" title="Moose (Perl)">Moose</a></li>

<li><a href="Plack_(software)" title="Plack (software)">Plack</a></li>

<li><a href="Template_Toolkit" title="Template Toolkit">Template Toolkit</a></li></ul>

</div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%">Software</th><td class="navbox-list-with-group navbox-list navbox-odd" style="width:100%;padding:0"><div style="padding:0 0.25em">

<ul><li><a href="Amavis" title="Amavis">Amavis</a></li>

<li><a href="Argus_(monitoring_software)" title="Argus (monitoring software)">Argus</a></li>

<li><a href="AWStats" title="AWStats">AWStats</a></li>

<li><a href="BackupPC" title="BackupPC">BackupPC</a></li>

<li><a href="Bricolage_(software)" title="Bricolage (software)">Bricolage</a></li>

<li><a href="Bugzilla" title="Bugzilla">Bugzilla</a></li>

<li><a href="Ikiwiki" title="Ikiwiki">ikiwiki</a></li>

<li><a href="Make_(software)#Modern_versions" title="Make (software)">Makepp</a></li>

<li><a href="Movable_Type" title="Movable Type">Movable Type</a></li>

<li><a href="Munin_(software)" title="Munin (software)">Munin</a></li>

<li><a href="Request_Tracker" title="Request Tracker">Request Tracker</a></li>

<li><a href="SpamAssassin" class="mw-redirect" title="SpamAssassin">SpamAssassin</a></li>

<li><a href="TWiki" title="TWiki">TWiki</a>/<a href="Foswiki" title="Foswiki">Foswiki</a></li>

<li><a href="Webmin" title="Webmin">Webmin</a></li></ul>

</div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%">Related</th><td class="navbox-list-with-group navbox-list navbox-even" style="width:100%;padding:0"><div style="padding:0 0.25em">

<ul><li><a href="Parrot_virtual_machine" title="Parrot virtual machine">Parrot</a></li>

<li>

<ul><li><a href="Rakudo" title="Rakudo">Rakudo</a></li>

<li><a href="Raku_rules" title="Raku rules">rules</a></li>

<li><a href="MoarVM" title="MoarVM">MoarVM</a></li></ul></li></ul>

</div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%">Books</th><td class="navbox-list-with-group navbox-list navbox-odd" style="width:100%;padding:0"><div style="padding:0 0.25em">

<ul><li><a href="Programming_Perl" title="Programming Perl">Programming Perl</a></li>

<li><a href="Learning_Perl" title="Learning Perl">Learning Perl</a></li>

<li><a href="Intermediate_Perl" title="Intermediate Perl">Intermediate Perl</a></li>

<li><a href="Perl_Best_Practices" class="mw-redirect" title="Perl Best Practices">Perl Best Practices</a></li></ul>

</div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%">People</th><td class="navbox-list-with-group navbox-list navbox-even" style="width:100%;padding:0"><div style="padding:0 0.25em">

<ul><li><a href="Larry_Wall" title="Larry Wall">Larry Wall</a></li>

<li><a href="Randal_L._Schwartz" title="Randal L. Schwartz">Randal L. Schwartz</a></li>

<li><a href="Damian_Conway" title="Damian Conway">Damian Conway</a></li>

<li><a href="Allison_Randal" title="Allison Randal">Allison Randal</a></li>

<li><a href="Audrey_Tang" title="Audrey Tang">Audrey Tang</a></li>

<li><a href="Sean_M._Burke" title="Sean M. Burke">Sean M. Burke</a></li>

<li><a href="Chromatic_(programmer)" title="Chromatic (programmer)">chromatic</a></li>

<li><a href="Brian_d_foy" title="Brian d foy">brian d foy</a></li>

<li><a href="Jesse_Vincent" title="Jesse Vincent">Jesse Vincent</a></li></ul>

</div></td></tr><tr><td class="navbox-abovebelow" colspan="2"><div>

<ul><li><a href="Outline_of_Perl" title="Outline of Perl">Outline</a></li>

<li>Category</li></ul>

</div></td></tr></tbody></table></div></div><div><div class="zim-footer">

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