ChaiScript/unittests/class_inheritance.chai

class Base
{
  attr x

  def Base()
  {
    this.x = 10
  }

  def do_something()
  {
    return this.x * 2
  }
}

class Derived : Base
{
  attr y

  def Derived()
  {
    this.x = 10
    this.y = 20
  }

  def do_other()
  {
    return this.y * 3
  }
}

// Test basic inheritance - derived can call base methods
auto d = Derived()
assert_equal(10, d.x)
assert_equal(20, d.y)
assert_equal(20, d.do_something())
assert_equal(60, d.do_other())

// Test base class still works independently
auto b = Base()
assert_equal(10, b.x)
assert_equal(20, b.do_something())

// Test method override
class Derived2 : Base
{
  def Derived2()
  {
    this.x = 5
  }

  def do_something()
  {
    return this.x * 100
  }
}

auto d2 = Derived2()
assert_equal(500, d2.do_something())

// Test passing a derived object to an untyped free function
def call_do_something_untyped(obj) {
  return obj.do_something()
}

auto d3 = Derived()
assert_equal(20, call_do_something_untyped(d3))
assert_equal(20, call_do_something_untyped(Base()))

// Test typed functions: parameter declared as Base, accepts derived objects
def call_do_something(Base obj) {
  return obj.do_something()
}

assert_equal(20, call_do_something(Base()))
assert_equal(20, call_do_something(d3))

// Test typed function accessing base attributes on a derived object
def get_x(Base obj) {
  return obj.x
}

assert_equal(10, get_x(d3))
assert_equal(10, get_x(Base()))

// Test polymorphic dispatch through typed function: derived override is called
auto d4 = Derived2()
assert_equal(500, call_do_something(d4))

// Test mixing base and derived in a container, calling base methods
var objects = [Base(), Derived(), Derived2()]
assert_equal(20, objects[0].do_something())
assert_equal(20, objects[1].do_something())
assert_equal(500, objects[2].do_something())

// Test that derived objects still report correct type
auto d5 = Derived()
assert_true(d5.is_type("Derived"))

// Test multi-level inheritance
class GrandChild : Derived
{
  attr z

  def GrandChild()
  {
    this.x = 1
    this.y = 2
    this.z = 3
  }

  def do_grandchild()
  {
    return this.z * 4
  }
}

auto gc = GrandChild()
assert_equal(1, gc.x)
assert_equal(2, gc.y)
assert_equal(3, gc.z)
assert_equal(2, gc.do_something())   // Base method
assert_equal(6, gc.do_other())       // Derived method
assert_equal(12, gc.do_grandchild()) // Own method

// Test passing grandchild to typed Base function (multi-level inheritance)
assert_equal(2, call_do_something(gc))
assert_equal(1, get_x(gc))

// Test typed function expecting mid-level type
def call_do_other(Derived obj) {
  return obj.do_other()
}

assert_equal(6, call_do_other(gc))
assert_equal(60, call_do_other(Derived()))