7. Dragon ADR Position Set

  • ADR - Architecture Design Records

7.1. Problem

  • Set new position to x=10, y=20

7.2. Option 1

>>> dragon.fly(10, 20)
>>> dragon.teleport(10, 20)
>>> dragon.set_position(10, 20)
>>> dragon.set_position_xy(10, 20)

  • Good: easy to use

  • Good: encapsulation

  • Good: easy to add validation if needed

  • Good: easy to extend to 3D - add parameter with default value 0

  • Bad: name set_position_xy() ties you to 2D point

  • Bad: arguments are implicit, require knowledge of an API

  • Bad: teleport() and fly() are bad names, does not indicate context what are the values provided as arguments

7.3. Option 2

>>> dragon.fly(x=10, y=20)
>>> dragon.teleport(x=10, y=20)
>>> dragon.set_position(x=10, y=20)

  • Good: easy to use

  • Good: arguments are explicit

  • Good: encapsulation

  • Good: easy to add validation if needed

  • Good: easy to extend to 3D - add parameter with default value 0

  • Bad: teleport() and fly() are bad names, to use-case specific

7.4. Option 3

>>> dragon.set(position_x=10, position_y=20)

  • Good: easy to use

  • Good: arguments are explicit

  • Good: encapsulation

  • Good: easy to add validation if needed

  • Bad: set() is to generic

  • Bad: gateway to abuse

7.5. Option 4

>>> dragon.x = 10
>>> dragon.y = 20

>>> dragon.x, dragon.y = 10, 20

  • Good: easy to use

  • Good: arguments are explicit

  • Good: can use @property for validation if needed

  • Bad: encapsulation

  • Bad: names x and y are weakly related to dragon

Example:

>>> knn = KNearestNeighbors(k=3)
>>> knn.w = [1, 2, 3]

7.6. Option 5

>>> dragon.position_x = 10
>>> dragon.position_y = 20

>>> dragon.position_x, dragon.position_y = 10, 20

  • Good: easy to use

  • Good: arguments are explicit

  • Good: can use @property for validation if needed

  • Bad: encapsulation

Example:

>>> knn = KNearestNeighbors(k=3)
>>> knn.weights = [1, 2, 3]

7.7. Option 6

>>> dragon.position = (10, 20)
>>> dragon.position @ (10, 20)

  • Good: easy to use

  • Good: can use @property for validation if needed

  • Good: using @ (matmul) it is easy to validation

  • Bad: @ (at) makes sense only in English

  • Bad: arguments are implicit

  • Bad: require knowledge of an API

  • Bad: always 2D

  • Bad: not extensible, hard to refactor to 3D

7.8. Option 7

>>> dragon.position = Point(x=10, y=20)
>>> dragon.position @ Point(x=10, y=20)

  • Good: easy to use

  • Good: can use @property for validation if needed

  • Good: arguments are explicit

  • Good: readability

  • Bad: @ (at) makes sense only in English

  • Bad: require knowledge of an API

  • Bad: extensible, easy to refactor to 3D

7.9. Option 8

>>> dragon.position.x = 10
>>> dragon.position.y = 20

>>> dragon.position.x, dragon.position.y = 10, 20

  • Good: more or less easy to use

  • Good: arguments are explicit

  • Good: can use @property for validation if needed

  • Good: namespace

  • Good: more or less readable

  • Good: extensible, easy to refactor to 3D

  • Bad: encapsulation

  • Bad: nested

  • Bad: require knowledge of an API

7.10. Decision

>>> dragon.set_position(x=10, y=20)

  • Good: easy to use

  • Good: arguments are explicit

  • Good: encapsulation

  • Good: easy to add validation if needed

  • Good: extensible, easy to refactor to 3D