updated from Atlas

11-pythonic-obj/mem_test.py

@@ -4,20 +4,25 @@ import resource
 
 NUM_VECTORS = 10**7
 
+module = None
 if len(sys.argv) == 2:
     module_name = sys.argv[1].replace('.py', '')
     module = importlib.import_module(module_name)
 else:
     print(f'Usage: {sys.argv[0]} <vector-module-to-test>')
-    sys.exit(2)  # command line usage error
 
-fmt = 'Selected Vector2d type: {.__name__}.{.__name__}'
-print(fmt.format(module, module.Vector2d))
+if module is None:
+    print('Running test with built-in `complex`')
+    cls = complex
+else:
+    fmt = 'Selected Vector2d type: {.__name__}.{.__name__}'
+    print(fmt.format(module, module.Vector2d))
+    cls = module.Vector2d
 
 mem_init = resource.getrusage(resource.RUSAGE_SELF).ru_maxrss
-print(f'Creating {NUM_VECTORS:,} Vector2d instances')
+print(f'Creating {NUM_VECTORS:,} {cls.__qualname__!r} instances')
 
-vectors = [module.Vector2d(3.0, 4.0) for i in range(NUM_VECTORS)]
+vectors = [cls(3.0, 4.0) for i in range(NUM_VECTORS)]
 
 mem_final = resource.getrusage(resource.RUSAGE_SELF).ru_maxrss
 print(f'Initial RAM usage: {mem_init:14,}')

11-pythonic-obj/patterns.py

@@ -0,0 +1,53 @@
+from vector2d_v3 import Vector2d
+
+# tag::KEYWORD_PATTERNS[]
+def keyword_pattern_demo(v: Vector2d) -> None:
+    match v:
+        case Vector2d(x=0, y=0):
+            print(f'{v!r} is null')
+        case Vector2d(x=0):
+            print(f'{v!r} is vertical')
+        case Vector2d(y=0):
+            print(f'{v!r} is horizontal')
+        case Vector2d(x=x, y=y) if x==y:
+            print(f'{v!r} is diagonal')
+        case _:
+            print(f'{v!r} is awesome')
+# end::KEYWORD_PATTERNS[]
+
+# tag::POSITIONAL_PATTERNS[]
+def positional_pattern_demo(v: Vector2d) -> None:
+    match v:
+        case Vector2d(0, 0):
+            print(f'{v!r} is null')
+        case Vector2d(0):
+            print(f'{v!r} is vertical')
+        case Vector2d(_, 0):
+            print(f'{v!r} is horizontal')
+        case Vector2d(x, y) if x==y:
+            print(f'{v!r} is diagonal')
+        case _:
+            print(f'{v!r} is awesome')
+# end::POSITIONAL_PATTERNS[]
+
+
+def main():
+    vectors = (
+        Vector2d(1, 1),
+        Vector2d(0, 1),
+        Vector2d(1, 0),
+        Vector2d(1, 2),
+        Vector2d(0, 0),
+    )
+    print('KEYWORD PATTERNS:')
+    for vector in vectors:
+        keyword_pattern_demo(vector)
+
+    print('POSITIONAL PATTERNS:')
+    for vector in vectors:
+        positional_pattern_demo(vector)
+
+
+
+if __name__ == '__main__':
+    main()

11-pythonic-obj/slots.rst

@@ -0,0 +1,52 @@
+# tag::PIXEL[]
+>>> class Pixel:
+...     __slots__ = ('x', 'y')  # <1>
+...
+>>> p = Pixel()  # <2>
+>>> p.__dict__  # <3>
+Traceback (most recent call last):
+  ...
+AttributeError: 'Pixel' object has no attribute '__dict__'
+>>> p.x = 10  # <4>
+>>> p.y = 20
+>>> p.color = 'red'  # <5>
+Traceback (most recent call last):
+  ...
+AttributeError: 'Pixel' object has no attribute 'color'
+
+# end::PIXEL[]
+
+# tag::OPEN_PIXEL[]
+>>> class OpenPixel(Pixel):  # <1>
+...     pass
+...
+>>> op = OpenPixel()
+>>> op.__dict__  # <2>
+{}
+>>> op.x = 8  # <3>
+>>> op.__dict__  # <4>
+{}
+>>> op.x  # <5>
+8
+>>> op.color = 'green'  # <6>
+>>> op.__dict__  # <7>
+{'color': 'green'}
+
+# end::OPEN_PIXEL[]
+
+# tag::COLOR_PIXEL[]
+>>> class ColorPixel(Pixel):
+...    __slots__ = ('color',)  # <1>
+>>> cp = ColorPixel()
+>>> cp.__dict__  # <2>
+Traceback (most recent call last):
+  ...
+AttributeError: 'ColorPixel' object has no attribute '__dict__'
+>>> cp.x = 2
+>>> cp.color = 'blue'  # <3>
+>>> cp.flavor = 'banana'
+Traceback (most recent call last):
+  ...
+AttributeError: 'ColorPixel' object has no attribute 'flavor'
+
+# end::COLOR_PIXEL[]

11-pythonic-obj/vector2d_v3.py

@@ -72,7 +72,7 @@ Tests of `x` and `y` read-only properties:
     >>> v1.x = 123
     Traceback (most recent call last):
       ...
-    AttributeError: can't set attribute
+    AttributeError: can't set attribute 'x'
 
 
 Tests of hashing:
@@ -90,6 +90,8 @@ from array import array
 import math
 
 class Vector2d:
+    __match_args__ = ('x', 'y')
+
     typecode = 'd'
 
     def __init__(self, x, y):

11-pythonic-obj/vector2d_v3_prophash.py

@@ -72,7 +72,7 @@ Tests of `x` and `y` read-only properties:
     >>> v1.x = 123
     Traceback (most recent call last):
       ...
-    AttributeError: can't set attribute
+    AttributeError: can't set attribute 'x'
 
 # end::VECTOR2D_V3_HASH_DEMO[]
 
@@ -112,7 +112,7 @@ class Vector2d:
     def __iter__(self):
         return (i for i in (self.x, self.y))  # <6>
 
-    # remaining methods follow (omitted in book listing)
+    # remaining methods: same as previous Vector2d
 # end::VECTOR2D_V3_PROP[]
 
     def __repr__(self):

11-pythonic-obj/vector2d_v3_slots.py

@@ -72,7 +72,7 @@ Tests of `x` and `y` read-only properties:
     >>> v1.x = 123
     Traceback (most recent call last):
       ...
-    AttributeError: can't set attribute
+    AttributeError: can't set attribute 'x'
 
 Tests of hashing:
 
@@ -90,11 +90,10 @@ import math
 
 # tag::VECTOR2D_V3_SLOTS[]
 class Vector2d:
-    __slots__ = ('__x', '__y')
+    __match_args__ = ('x', 'y')  # <1>
+    __slots__ = ('__x', '__y')  # <2>
 
     typecode = 'd'
-
-    # methods follow (omitted in book listing)
 # end::VECTOR2D_V3_SLOTS[]
 
     def __init__(self, x, y):