This raku module is one of the core libraries of the raku Air distribution.
It is a scaffold to build dynamic, reusable web components.
The synopsis is split so that each part can be annotated. First, we import the Air core libraries.
use Air::Functional :BASE; # import all HTML tags as raku subs
use Air::Base; # import Base components (site, page, nav...)
use Air::Component;
We prepare some custom HTMX actions for our Todo component. This declutters class Todo and keeps our hx-attrs tidy and local.
role HxTodo {
method hx-create(--> Hash()) {
:hx-post("todo"),
:hx-target<table>,
:hx-swap<beforeend>,
}
method hx-delete(--> Hash()) {
:hx-delete($.url-id),
:hx-confirm<Are you sure?>,
:hx-target<closest tr>,
:hx-swap<delete>,
}
method hx-toggle(--> Hash()) {
:hx-get("$.url-id/toggle"),
:hx-target<closest tr>,
:hx-swap<outerHTML>,
}
}
Key features are:
these are packaged in a raku role which is then consumed by class Todo
method names hx-toggle echo standard HTMX attributes such as hx-get
return values are coerced to a raku Hash containing HTMX attrs
The core of our synopsis. It does Component to bring in the scaffolding.
The general idea is that a raku class implements a web Component, multiple instances of the Component are represented by objects of the class and the methods of the class represent actions that can be performed on the Component in the browser.
class Todo does Component {
also does HxTodo;
has Bool $.checked is rw = False;
has Str $.text;
method toggle is controller {
$!checked = !$!checked;
respond self;
}
multi method HTML {
tr
td( input :type<checkbox>, |$.hx-toggle, :$!checked ),
td( $!checked ?? del $!text !! $!text),
td( button :type<submit>, |$.hx-delete, :style<width:50px>, '-'),
}
}
Key features of class Todo are:
Todo objects have state $.checked and $.text with suitable defaults
method toggle takes the trait is controller - this makes a corresponding Cro route
method toggle adjusts the state and ends with the respond sub (which calls .HTML)
class Todo provides a multi method HTML which uses functional HTML tags tr, td and so on
we call our HxTodo methods eg |$.hx-toggle with the call self shorthand $.
the Hash is flattened into individual attrs with |
a smattering of style (or any HTML attr) can be added as needed
The result is a concise, legible and easy-to-maintain component implementation.
Now, we can make a website as follows:
my &index = &page.assuming(
title => 'hÅrc',
description => 'HTMX, Air, Red, Cro',
footer => footer p ['Aloft on ', b 'Åir'],
);
my @todos = do for <one two> -> $text { Todo.new: :$text };
sub SITE is export {
site :components(@todos),
index
main [
h3 'Todos';
table @todos;
form |Todo.hx-create, [
input :name<text>;
button :type<submit>, '+';
];
]
}
Key features of sub SITE are:
we make our own function &index that
(i) uses .assuming to preset some attributes (title, description, footer) and
(ii) then calls the page function provided by Air::Base
we set up our list of Todo components calling Todo.new
we use the Air::Base site function to make our website
the call chain site(index(main(...)) then makes our website
site is passed :components(@todos) to make the component Cro routes
Component automagically creates some cro routes for Todo when we start our website…
> raku -Ilib service.raku
theme-color=green
bold-color=red
adding GET todo/<#>
adding POST todo
adding DELETE todo/<#>
adding PUT todo/<#>
adding GET todo/<#>/toggle
adding GET page/<#>
Build time 0.67 sec
Listening at http://0.0.0.0:3000
The rationale for Air Components is rooted in the powerful raku code composition capabilities. It builds on the notion of Locality of Behaviour (aka LOB) and the intent is that a Component can represent and render every aspect of a piece of website behaviour.
Content
Layout
Theme
Data Model
Actions
As Air evolves, it is expected that common code idioms will emerge to make each dimensions independent (ie HTML, CSS and JS relating to Air::Theme::Font would be local, and distinct from HTML, CSS and JS for Air::Theme::Nav).
Air is an integral part of the hArc stack (HTMX, Air, Red, Cro). The Synopsis shows how a Component can externalize and consume HTMX attributes for method actions, perhaps even a set of Air::HTMX libraries can be anticipated. One implication of this is that each Component can use the hx-swap-oob attribute to deliver Content, Style and Script anywhere in the DOM (except the html tag). An instance of this could be a blog website where a common Red model Post could be harnessed to populate each blog post, a total page count calculation for paging and a post summary list in an aside.
In the Synopsis, both raku class inheritance and role composition provide coding dimensions to greatly improve code clarity and evolution. While simple samples are shown, raku has comprehensive encapsulation and type capabilities in a friendly and approachable language.
Raku is a multi-paradigm language for both Functional and Object Oriented (OO) coding styles. OO is a widely understood approach to code and state encapsulation - suitable for code evolution across many aspects - and is well suited for Component implementations. Functional is a surprisingly good paradigm for embedding HTML standard and custom tags into general raku source code. The example below illustrates the power of Functional tags inline when used in more intricate stanzas.
While this kind of logic can in theory be delivered in a web app using web template files, as the author of the Cro Template language comments Those wishing for more are encouraged to consider writing their logic outside of the template.
method nav-items {
do for @.items.map: *.kv -> ($name, $target) {
given $target {
when * ~~ External | Internal {
$target.label = $name;
li $target.HTML
}
when * ~~ Content {
li a(:hx-get("$.name/$.serial/" ~ $name), safe $name)
}
when * ~~ Page {
li a(:href("/{.name}/{.serial}"), safe $name)
}
}
}
}
multi method HTML {
self.style.HTML ~ (
nav [
{ ul li :class<logo>, :href</>, $.logo } with $.logo;
button( :class<hamburger>, :serial<hamburger>, safe '☰' );
ul( :$!hx-target, :class<nav-links>,
self.nav-items,
do for @.wserialgets { li .HTML },
);
ul( :$!hx-target, :class<menu>, :serial<menu>,
self.nav-items,
);
]
) ~ self.script.HTML
}
From the implementation of the Air::Base::Nav component.
When writing components:
multi method HTML inners must be explicitly rendered with .HTML or wrapped in a tag eg. div since being passed as AN inner will call render-tag which will, in turn, call .HTMLassigns and tracks instance serials
optional attr to specify url base
method holder() returns Hash
populates an instance holder [class method], may be overridden for external instance holder
method all() returns Mu
get all instances in holder
method name() returns Mu
get url safe name of class doing Component role
method url() returns Str
get url (ie base/name)
method url-id() returns Str
get url-id (ie base/name/serial)
method id() returns Str
get html friendly id (ie name-serial), eg for html id attr
method MYLOAD(
$serial
) returns Mu
Default load action (called on GET) - may be overridden
method MYCREATE(
*%data
) returns Mu
Default create action (called on POST) - may be overridden
method MYDELETE() returns Mu
Default delete action (called on DELETE) - may be overridden
method MYUPDATE(
*%data
) returns Mu
Default update action (called on PUT) - may be overridden
method add-routes(
$component is copy,
:$comp-name = Code.new
) returns Mu
Meta Method ^add-routes typically called from Air::Base::Site in a Cro route block
multi sub respond(
$comp
) returns Mu
calls Cro: content ‘text/html’, $comp.HTML
multi sub respond(
Str $html
) returns Mu
calls Cro: content ‘text/html’, $html
Steve Roe librasteve@furnival.net
The Air::Component module provided is based on an early version of the raku Cromponent module, author Fernando Corrêa de Oliveira fco@cpan.com, however unlike Cromponent this module does not use Cro Templates.
Copyright(c) 2025 Henley Cloud Consulting Ltd.
This library is free software; you can redistribute it and/or modify it under the Artistic License 2.0.