Classes
A class is a declaration of a constructor of objects with a specific type. Each object has zero or more attributes (instance variables) with zero or more behaviours (methods), that are defined inside a specific class or inherited from super-classes.
class Person (name, age, address) {
method position {
# GPS.locate(self.address)
}
method increment_age(amount=1) {
self.age += amount
}
}
var obj = Person(
name: "Foo",
age: 50,
address: "St. Bar"
)
say obj.age # prints: 50
say obj.name # prints: "Foo"
say obj.address # prints: "St. Bar"
obj.name = "Baz" # changes name to "Baz"
say obj.name # prints: "Baz"
obj.increment_age # increments age by 1
say obj.age # prints: 51

Class attributes

The attributes of a class can be either specified as parameters, or declared with the has keyword.
class Example(a, b) {
has c = 3
has d = a+c
}
var obj = Example(1, 2)
say obj.a #=> 1
say obj.b #=> 2
say obj.c #=> 3
say obj.d #=> 4

Class initialization

Extra object-initialization setup can be done by defining a method named init, which will be called automatically called whenever a new instance-object is created.
class Example (a, b) {
has r = 0
method init { # called automatically
r = a+b
}
method foo {
r
}
}
var obj = Example(3, 4)
say obj.foo #=> 7

Class variables

The syntax ClassName!var_name can be used for defining, accessing or modifying a class variable.
class Example {
Example!hidden = 'secret' # global class variable
method concat (str) {
str + ' ' + Example!hidden
}
}
var x = Example()
var y = Example()
say x.concat('foo') #=> 'foo secret'
say y.concat('bar') #=> 'bar secret'
Example!hidden = 'public' # changing the class variable
say x.concat('foo') #=> 'foo public'
say y.concat('bar') #=> 'bar public'
The modification of a class variable can be localized by prefixing the declaration with the local keyword:
local Example!hidden = 'local value'

Class inheritance (experimental)

Inheritance of behaviors and attributes, by a given class, is declared with the < operator, followed by the name of the class from which the current class inherits:
class Animal(String name, Number age) {
method speak { "..." }
}
class Dog(String color) < Animal {
method speak { "woof" }
method ageHumanYears { self.age * 7 }
}
class Cat < Animal {
method speak { "meow" }
}
var dog = Dog(name: "Sparky", age: 6, color: "white")
var cat = Cat(name: "Mitten", age: 3)
say dog.speak #=> woof
say cat.speak #=> meow
say cat.age #=> 3
say dog.ageHumanYears #=> 42
say dog.color #=> white
Multiple inheritance is declared with the << operator, followed by two or more class names, separated by commas:
class Camera { }
class MobilePhone { }
class CameraPhone << Camera, MobilePhone { }
Last modified 2yr ago