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Version 3.5 by chrisby on 2024/03/03 15:17
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1 ### Use Cases
2
3 This example is intended to demonstrate the extensibility differences between data structures and objects by extending them with
4
5 1. an Area() function (extending behavior)
6 1. a rectangle type (extending data type)
7
8 ### Data Structure Style
9
10 struct Square {
11 length float
12 }
13
14 struct Circle {
15 radius float
16 }
17
18 function Circumference(g Object) float {
19 switch type(g):
20 case Square:
21 return 4 * g.length
22 case Circle:
23 return 2 * PI * g.radius
24 }
25
26 1. Adding a function Area() with the same anatomy as Circumference() is easy, since it only requires adding new code.
27 1. Adding a new datatype, Rectangle, is more difficult because it requires touching existing code, namely any functions like Circumference() or Area() that need to be enabled handle this datatype.
28
29 ####
30
31 #### Object-Oriented Style
32
33 interface GeometricObject {
34 Circumference() float
35 }
36
37 class Square implements GeometricObject {
38 length float
39
40 constructor(length float) {
41 this.length = length
42 }
43
44 func Circumference() float {
45 return 4 * this.length
46 }
47 }
48
49 class Circle implements GeometricObject {
50 radius float
51
52 constructor(radius float) {
53 this.radius = radius
54 }
55
56 func Circumference() float {
57 return 2 * PI * this.radius
58 }
59 }