6. Dragon ADR Init Position

  • ADR - Architecture Design Records

6.1. Problem

  • Create dragon at x=50, y=120 position

6.2. Option 1

>>> dragon = Dragon('Wawelski', 50, 120)

  • Good: easy to use

  • Bad: not explicit

  • Bad: requires knowledge of API to answer what are those numbers

  • Bad: It does suggest, that x and y are some parameters to texture (for example width and height of a texture image)

Problems:

>>> dragon = Dragon('Wawelski', 'img/dragon/alive.png', 50, 120)

>>> position = Position(1, 2)  # ok
>>> position = GPSPosition(1, 2)  # nie ok

6.3. Option 2

>>> dragon = Dragon('Wawelski', x=50, y=120)

  • Good: easy to use

  • Good: short argument names

  • Good: verbose in this example

  • Good: you can assign None by default to set default point

  • Good: extensible, easy to add z with default value 0

  • Bad: It does suggest, that x and y are some parameters to texture (for example width and height of a texture image)

Problems:

>>> dragon = Dragon('Wawelski', 'img/dragon/alive.png', x=50, y=120)

>>> position = Position(x=1, y=2)  # ok
>>> position = GPSPosition(x=1, y=2)  # nie ok

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

6.4. Option 3

>>> dragon = Dragon('Wawelski', posx=50, posy=120)
>>> dragon = Dragon('Wawelski', pos_x=50, pos_y=120)

  • Good: simple, easy to use

  • Good: you can assign None by default to set default point

  • Good: extensible, easy to add pos_z with default value 0

  • Bad: not verbose

Problem:

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

>>> position = GPSPosition(lo=1, la=2)  # nie ok
>>> position = GPSPosition(lon=1, lat=2)  # ok

6.5. Option 4

>>> dragon = Dragon('Wawelski', positionx=50, positiony=120)
>>> dragon = Dragon('Wawelski', position_x=50, position_y=120)

  • Good: simple, easy to use

  • Good: you can assign None by default to set default point

  • Good: extensible, easy to add position_z with default value 0

Problem:

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

>>> position = GPSPosition(longitude=1, latitude=2)  # ok

>>> df.plot(kind='line', subplots=True, color='grey', sharey=True)

Solution:

>>> df.plot(kind='line', subplots=True, color='grey', share_y=True)

6.6. Option 5

>>> dragon = Dragon('Wawelski', pos=(50, 120))
>>> dragon = Dragon('Wawelski', position=(50, 120))
>>> dragon = Dragon('Wawelski', pos=[50, 120])
>>> dragon = Dragon('Wawelski', position=[50, 120])

  • Good: data is stored together (coordinate)

  • Good: simple, easy to use

  • Good: you can assign None by default to set default position

  • Good: always has to pass both x and y

  • Bad: always has to pass both x and y

  • Bad: you have to know that first is x and second is y

  • Bad: order is important

  • Bad: unpacking

  • Bad: not extensible, position will always be 2D

Problem:

  • pattern = r'[\(\[\d+,\s*\d[\)\]]'

6.7. Option 6

>>> dragon = Dragon('Wawelski', posxy=(50, 120))
>>> dragon = Dragon('Wawelski', pos_xy=(50, 120))
>>> dragon = Dragon('Wawelski', position_xy=(50, 120))

  • Good: data is stored together (coordinate)

  • Good: simple, easy to use

  • Good: you can assign None by default to set default position

  • Good: always has to pass both x and y

  • Bad: always has to pass both x and y

  • Bad: you have to know that first is x and second is y

  • Bad: order is important

  • Bad: unpacking

  • Bad: not extensible, position_xy will always be 2D

Problem:

  • pattern = r'[\(\[\d+,\s*\d[\)\]]'

6.8. Option 7

>>> dragon = Dragon('Wawelski', pos={'x':50, 'y':120})
>>> dragon = Dragon('Wawelski', position={'x':50, 'y':120})

  • Good: data is stored together (coordinate)

  • Good: you can assign None by default to set default point

  • Good: order is not important

  • Good: always has to pass both x and y

  • Good: possible to extend to 3D with refactoring

  • Good: easier to refactor than tuple - pattern = r'\{"x":\d+, "y":\d+\}'

  • Bad: always has to pass both x and y

  • Bad: unpacking

  • Bad: not extensible, position will always be 2D

Problem:

  • pattern = r'\{"x":\d+, "y":\d+\}'

6.9. Option 8

>>> from collections import namedtuple
>>>
>>>
>>> Position = namedtuple('Position', ['x', 'y'])
>>>
>>> dragon = Dragon('Wawelski', Position(x=50, y=120))
>>> dragon = Dragon('Wawelski', position=Position(x=50, y=120))

  • Good: data is stored together (coordinate)

  • Good: simple, easy to use

  • Good: always has to pass both x and y

  • Good: relatively easy to extend to 3D

  • Good: keyword argument is not required, class name is verbose enough

  • Bad: always has to pass both x and y

  • Bad: not extensible, position will always be 2D

6.10. Option 9

>>> from typing import NamedTuple
>>>
>>>
>>> class Position(NamedTuple):
...     x: int = 0
...     y: int = 0
>>>
>>>
>>> dragon = Dragon('Wawelski', Position(x=50, y=120))
>>> dragon = Dragon('Wawelski', position=Position(x=50, y=120))

  • Good: data is stored together (coordinate)

  • Good: simple, easy to use

  • Good: verbose

  • Good: you can assign None by default to set default position

  • Good: very easy to extend to 3D

  • Good: keyword argument is not required, class name is verbose enough

6.11. Option 10

>>> from typing import TypedDict
>>>
>>>
>>> class Position(TypedDict):
...     x: int
...     y: int
>>>
>>>
>>> pt1 = Position(x=50, y=120)
>>> pt2: Position = {'x': 50, 'y': 120}
>>>
>>> dragon = Dragon('Wawelski', position=pt1)
>>> dragon = Dragon('Wawelski', position=pt2)

  • Good: data is stored together (coordinate)

  • Good: simple

  • Good: you can assign position=None by default to set default position

  • Good: relatively easy to extend to 3D

  • Good: keyword argument is not required, class name is verbose enough

  • Bad: before Python 3.11 TypeDict does not support default values

Future:

  • API will change in Python 3.11

  • Will include Required and NotRequired

  • Will support default values

  • Re-evaluate then

6.12. Option 11

>>> from dataclasses import dataclass
>>>
>>>
>>> @dataclass
... class Point:
...     x: int = 0
...     y: int = 0
>>>
>>>
>>> dragon = Dragon('Wawelski', Point(50, 120))
>>> dragon = Dragon('Wawelski', position=Point(50, 120))
>>> dragon = Dragon('Wawelski', Point(x=50, y=120))
>>> dragon = Dragon('Wawelski', position=Point(x=50, y=120))

  • Good: data is stored together (coordinate)

  • Good: simple, easy to use

  • Good: verbose

  • Good: you can assign None by default to set default position

  • Good: very easy to extend to 3D

  • Good: keyword argument is not required, class name is verbose enough

6.13. Option 12

>>> from dataclasses import dataclass
>>>
>>>
>>> @dataclass(frozen=True, slots=True)
... class Point:
...     x: int = 0
...     y: int = 0
>>>
>>>
>>> dragon = Dragon('Wawelski', Point(50, 120))
>>> dragon = Dragon('Wawelski', position=Point(50, 120))
>>> dragon = Dragon('Wawelski', Point(x=50, y=120))
>>> dragon = Dragon('Wawelski', position=Point(x=50, y=120))

  • Good: data is stored together (coordinate)

  • Good: simple, easy to use

  • Good: verbose

  • Good: you can assign None by default to set default position

  • Good: very easy to extend to 3D

  • Good: keyword argument is not required, class name is verbose enough

  • Good: is faster and leaner than simple dataclass

  • Bad: more complicated than mutable dataclasses

6.14. Option 13

>>> class Point:
...     x: int
...     y: int
...
...     def __init__(self, x: int = 0, y: int = 0) -> None:
...         self.x = x
...         self.y = y
>>>
>>>
>>> dragon = Dragon('Wawelski', Point(50, 120))
>>> dragon = Dragon('Wawelski', position=Point(50, 120))
>>> dragon = Dragon('Wawelski', Point(x=50, y=120))
>>> dragon = Dragon('Wawelski', position=Point(x=50, y=120))

  • Good: very common

  • Good: easy to use

  • Good: faster than dataclasses

  • Good: more explicit than dataclass

  • Good: easy to extend to 3D

  • Good: can set default values

  • Good: keyword argument is not required, class name is verbose enough

6.15. Option 14

>>> class Point:
...     __slots__ = ('x', 'y')
...     x: int
...     y: int
...
...     def __init__(self, x: int = 0, y: int = 0) -> None:
...         self.x = x
...         self.y = y
>>>
>>>
>>> dragon = Dragon('Wawelski', Point(50, 120))
>>> dragon = Dragon('Wawelski', position=Point(50, 120))
>>> dragon = Dragon('Wawelski', Point(x=50, y=120))
>>> dragon = Dragon('Wawelski', position=Point(x=50, y=120))

  • Good: very common

  • Good: easy to use

  • Good: more explicit than dataclass

  • Good: easy to extend to 3D

  • Good: can set default values

  • Good: keyword argument is not required, class name is verbose enough

  • Bad: too complex for now

6.16. Decision

>>> dragon = Dragon('Wawelski', position_x=50, position_y=120)

  • Good: simple

  • Good: explicit

  • Good: verbose

  • Good: extensible

Alternative - maybe in future:

>>> dragon = Dragon('Wawelski', position=Point(x=50, y=120))

  • Choices: NameTuple, dataclass(frozen=True, slots=True)

  • Good: explicit

  • Good: verbose

  • Good: extensible

  • Bad: to complex for now