# 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 enough

• 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, or gold and hit points)

• Verdict: rejected, not explicit

Problems:

>>> dragon = Dragon('Wawelski', 0, 0)
>>> dragon = Dragon('Wawelski', None, None)
>>> dragon = Dragon('Wawelski', 'img/dragon/alive.png', 50, 120)

>>> pt = Point(1, 2)                # maybe
>>> pt = PointXY(1, 2)              # ok, but the name is overkill
>>> pt = CartesianAxisPoint(1, 2)   # ok
>>> pt = GPSPoint(1, 2)             # bad


## 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)

• Verdict: rejected, not explicit enough

Problems:

>>> dragon = Dragon('Wawelski', x=0, y=0)
>>> dragon = Dragon('Wawelski', x=None, y=None)
>>> dragon = Dragon('Wawelski', 'img/dragon/alive.png', x=50, y=120)

>>> pt = Point(x=1, y=2)                        # ok
>>> pt = PointXY(x=1, y=2)                      # ok, but the name is overkill
>>> pt = CartesianAxisPoint(x=1, y=2)           # ok
>>> pt = GPSPoint(x=1, y=2)                     # bad, GPS uses lon, lat

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


## 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

• Verdict: rejected, not explicit enough

Problem:

>>> dragon = Dragon('Wawelski', posx=0, posy=0)         # maybe, bad
>>> dragon = Dragon('Wawelski', pos_x=None, pos_y=None) # maybe, bad
>>> knn = KNearestNeighbors(k=3, wgt=[1,2,3])           # bad

>>> pt = GPSPoint(lo=1, la=2)       # bad
>>> pt = GPSPoint(lon=1, lat=2)     # ok


## 6.5. Option 4¶

>>> dragon = Dragon('Wawelski', positionx=50, positiony=120)
>>> dragon = Dragon('Wawelski', positionX=50, positionY=120)

• Good: simple, easy to use

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

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

• Verdict: candidate, but names could be better

Problem:

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


## 6.6. Option 5¶

>>> 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

• Verdict: candidate

Problem:

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


Solution:

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


## 6.7. Option 6¶

>>> 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 to set default position

• Good: always has to pass both x and y coordinates together

• Bad: always has to pass both x and y coordinates together

• Bad: cannot set only one axis to None

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

• Bad: order is important, you cannot change it

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

• Verdict: rejected, not extensible

Problem:

>>> dragon = Dragon('Wawelski', pos=[0, 0])         # ok
>>> dragon = Dragon('Wawelski', pos=[None, None])   # maybe

• pattern = r'[$$$\d+,\s*\d[$$$]'

## 6.8. Option 7¶

>>> 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: not extensible, position_xy will always be 2D

• Verdict: rejected, not extensible

Problem:

• pattern = r'[$$$\d+,\s*\d[$$$]'

## 6.9. Option 8¶

>>> 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: not extensible, position will always be 2D

• Verdict: rejected, not extensible

Problem:

• pattern = r'\{"x":\d+, "y":\d+\}'

## 6.10. Option 9¶

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

• Good: lightweight, in the end this is a tuple

• Bad: always has to pass both x and y

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

• Verdict: rejected, could be done better

## 6.11. Option 10¶

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

• Good: lightweight, in the end this is a tuple

• Verdict: candidate

## 6.12. Option 11¶

>>> 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

• Verdict: rejected, re-evaluate in future

Future:

• API will change in Python 3.11

• Will include Required and NotRequired

• Will support default values

• Re-evaluate then

## 6.13. Option 12¶

>>> 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

• Verdict: maybe, has some limitation

>>> pt = Point(x=1, y=2)
>>> pt.x = 1             # will pass
>>> pt.y = 2             # will pass
>>> pt.notexisting = 10  # will pass


## 6.14. Option 13¶

>>> 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

• Verdict: maybe, too complex for now

>>> pt = Point(x=1, y=2)
>>> pt.x = 1             # will pass
>>> pt.y = 2             # will pass
>>> pt.notexisting = 10  # will throw error


## 6.15. Option 14¶

>>> 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 to set default position

• Good: very easy to extend to 3D

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

• Verdict: maybe, has some limitation

>>> pt = Point(x=1, y=2)
>>> pt.x = 1             # will pass
>>> pt.y = 2             # will pass
>>> pt.notexisting = 10  # will pass


## 6.16. Option 15¶

>>> 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

• Verdict: candidate

Good:

>>> pt = Point(x=1, y=2)
>>> pt.x = 1             # will throw error
>>> pt.y = 2             # will throw error
>>> pt.notexisting = 10  # will throw error


## 6.17. Decision¶

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

• Good: simple

• Good: explicit

• Good: verbose

• Good: extensible

Re-evaluate 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 complicated for now