Context-Oriented
Algorithmic Design
Bruno Ferreira
António Menezes Leitão

Algorithmic Design

2

CAD Tools

3

BIM Tools

4

BIM Tools

5

Complex Buildings

6

Complex Buildings

7

Need For Analysis

8

Several Tools

9

Khepri

10

Khepri

11

Khepri

12

Khepri

13

Code can become messy

14

15

One script for all models

16

Context-Oriented Programming

COP
> Behavioral Variations
> Layers
> Activation mechanism
> Context
> Scoping

17

Objectives

> Present and compare COP
> Combine COP with AD

18

Related Work

19

Aspect-Oriented Programming
> Cross-cutting concerns
> Aspects
> Pointcuts, Join Points, Advice

20

Subject-Oriented Programming
> Subjects
> Subject-activation
> Subjective Dispatch

21

Context-Oriented Programming

> Contexts
> Contextual Dispatch

22

ContextL
> Common Lisp
> Dynamically Scoped Layer Activation
> Layered Generic Functions
> Layer-in-class and class-in-layer

23

ContextL
(deflayer employment-layer)
(with-active-layers (employment-layer)
... contained code ...)
(define-layered-class employer
:in-layer employment-layer ()
((name :initarg :name
:layered-accessor employer-name)))

24

ContextPy
> Python
> Dinamically Scoped Layer Activation
> Decorators
> Layer-in-class

25

ContextPy
class Slab:
@around(a3DLayer)
def generate(self):
return extrusion(surface_from(self.path),
self.thickness)
@around(a2DLayer)
def generate(self):
return self.path

26

ContextJ
> Java (source-to-source compiler)
> Dynamically Scoped Layer Activation
> Reflection API
> Layer-in-class

27

ContextJ
class Employer{
String toString() {
return “Name: ” + name;
}
layer Address {
String toString() {
return proceed() + “; Address: ” + ...
}
}

28

Lambic
> Common Lisp
> Predicate Dispatch
> Activation with Predicates
> Different modularization

29

Lambic
(defgeneric factorial (n)
(:predicates < = >))
(defmethod factorial (n)
(:when (> n 0))
(* n (factorial (- n 1))))
(defmethod factorial (n)
(:when (= n 0))
1)

30

Comparison

31

32

Context-Oriented
Algorithmic Design

33

COAD
BIM

CAD

Energy
Program

Radiation

Structural

34

Implementation
Visualization
Tool

COP Library

Rendering
Tool

Khepri

Analysis Tool
…

Implementation

> ContextScheme (adapted to Racket)
> Khepri

35

Case Study

36

Case Study

37

Original Version
(define (shop-2d ...)
(...
(line ...)
(rectangle ...)
...))
(define (shop-3d ...)
(...
(right-cuboid ...)
...))

38

Original Version

(define (mall ... shop ...)
(...
(shop ... )
...))

39

COP Version
(define (shop p v l w)
(...
((wall) p0 p1 wall-thickness wall-height)
...
((door) ((wall) p2 p3 wall-thickness wall-height)
p4 p5 wall-thickness door-height))))

40

COP Version

(with-layers (2D)
(mall (xy 0 0) 100000 12000 25000 7000 7000 4))

41

COP 2D

42

COP 3D

43

COP Analysis

44

Partial Modelling

45

Partial Modelling

46

Advantages

> Reduces the code
> Dynamic context change

47

Evaluation

48

Evaluation
> Higher-order or not?
> Implicit or Explicit Activation?
> Performance?

49

Future Work

50

Thank you!
Questions?
bruno.b.ferreira@tecnico.ulisboa.pt
antonio.menezes.leitao@tecnico.ulisboa.pt
https://algorithmicdesign.github.io/