Object Interfaces

• Duck Typing
• Meta-Method Checks
• Interfaces

Duck Typing 

If it looks like a duck, and quacks like a duck, we have at least to consider the possibility that we have a small aquatic bird of the family anatidae on our hands.

— Douglas Adams

Like PHP, THT is a dynamically typed language. This means that an object’s class or type does not need to be checked before you can call its methods.

This lets you use objects from different classes in the same way, as long as they define the same methods.

This is also referred to as Duck Typing, because if an object “walks like a duck, and talks like a duck... then it’s a duck.”

Example

In this example, two classes have a talk method.

class Cat {
    fun talk: print('>Meow<')
}

class Coder {
    fun talk: print('1001010011101')
}

// Another File
//---------------------------------------

fun greet($creature) {
    // Any object that has a 'talk' method will work.
    $creature.talk()
}

$kitty = Cat()
greet($kitty)  //= '>Meow<'

$kody = Coder()
greet($kody)  //= '1001010011101'

Meta-Method Checks 

You can also use meta-methods like zHasMethod to explicitly check if an object has the given method.

fun greet($creature) {
    if $creature.zHasMethod('talk') {
        $creature.talk()
    }
}

Interfaces