Magic Methods
Magic methods are struct methods with a special name. These are not supposed to be called directly by the programmer but rather by the compiler.
Destructors
The destructor (__deinit__) is called when an object goes out of scope. This can for example be
used to automatically deallocate memory owned by the object when it is no longer needed. Adding a
destructor to a struct turns it into a resource.
use std.memory;
struct SmartPtr {
var ptr: addr;
func new(size: usize) -> SmartPtr {
return SmartPtr { ptr: memory.alloc(size) };
}
func __deinit__(self) {
memory.free(self.ptr);
}
}
func main() {
var ptr1 = SmartPtr.new(100);
{
var ptr2 = SmartPtr.new(20);
# Destructor of 'ptr2' is called here.
}
# Destructor of 'ptr1' is called here.
}
Operator Overloading
Some operators can be overloaded for structs.
struct Vec2 {
var x: i32;
var y: i32;
func __add__(self, rhs: Vec2) -> Vec2 {
return Vec2 {
x: self.x + rhs.x,
y: self.y + rhs.y
};
}
func __sub__(self, rhs: Vec2) -> Vec2 {
return Vec2 {
x: self.x - rhs.x,
y: self.y - rhs.y
};
}
func __mul__(self, rhs: i32) -> Vec2 {
return Vec2 {
x: self.x * rhs
y: self.y * rhs
};
}
}
func main() {
var a = Vec2 { x: 10, y: 30 };
var b = Vec2 { x: 5, y: -10 };
var c = a + b;
println(c.x); # 15
println(c.y); # 20
var d = a - b;
println(d.x); # 5
println(d.y); # 40
var e = a * 3;
println(e.x); # 30
println(e.y); # 90
}
These are the operators that can currently be overloaded:
Using Operators |
Using Magic Methods |
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