Merge remote-tracking branch 'origin/development' into development

Author: gjbex

source-code/typing/README.md

@@ -1,42 +1,40 @@
-# Typing
-Python 3.5 introducd optional type annotation for functions, and that
-functionality was extended in Python 3.6.
+# Typing Python 3.5 introducd optional type annotation for functions, and
+that functionality was extended in Python 3.6.
 
-The `mypy` static type checker can use this annotation to detect type
-errors.
+The `mypy` static type checker can use this annotation to detect type errors.
 
 Type checking can be done using [mypy](http://mypy-lang.org/index.html).
 
 ## What is it?
 1. `mypy.ini`: mypy configuration file.
 1. `correct.py`: code that has type annotations, and no type errors.
-1. `incorrect_01.py`: code that has type annotations, and passes a string
-    to a function that expects an `int`.
+1. `incorrect_01.py`: code that has type annotations, and passes a string to
+   a function that expects an `int`.
 1. `incorrect_02.py`: code that has type annotations, and the result of a
-    function that returns an `int` is assigned to a `str` variable.
+   function that returns an `int` is assigned to a `str` variable.
 1. `incorrect_03.py`: code that has type annotations, and the result of a
-    function that returns an `int`, assigns it to a variable that is
-    later used as a `str`.
-1. `dict_correct.py`: code that counts the words in a text read from
-    standard input.
+   function that returns an `int`, assigns it to a variable that is later
+   used as a `str`.
+1. `dict_correct.py`: code that counts the words in a text read from standard
+   input.
 1. `dict_incorrect.py`: code that counts the words in a text read from
-    standard input.  The counts are subsequently normalized to `float`,
-    which is a type error.
-1. `people_incorrect.py`: code that defines a `People` class, stores some
-    in a list with mistakes.
+   standard input.  The counts are subsequently normalized to `float`, which
+   is a type error.
+1. `people_incorrect.py`: code that defines a `People` class, stores some in
+   a list with mistakes.
 1. `duck_typing.py`: example code illustrating duck typing.
-1. `duck_typing_wrong.py`: example code illustrating duck typing, but
+1. `duck_typing_incorrect.py`: example code illustrating duck typing, but
    with an error.
-1. `typed_duck_typing.py`: example code illustrating duck typing
-   using type hints.
-1. `typed_duck_typing_wrong.py`: example code illustrating duck typing
+1. `typed_duck_typing.py`: example code illustrating duck typing using type
+   hints.
+1. `typed_duck_typing_clean.py`: example code illustrating duck typing using
+   type hints with a factory function.
+1. `typed_duck_typing_incorrect.py`: example code illustrating duck typing
    using type hints with an error.
-1. `typed_duck_typing_false_positive.py`: example code illustrating
-   duck typing using type hints for which mypy 0.910 generates a
-   false positive.
+1. `typed_duck_typing_false_positive.py`: example code illustrating duck
+   typing using type hints for which mypy 0.910 generates a false positive.
 1. `numpy_typing.py`: illustration of a script using both numpy and
    matplotlib with type hints.
-1. `classes.py`: illustration of using type hints with a user-defined
-   class.
+1. `classes.py`: illustration of using type hints with a user-defined class.
 1. `classes_incorrect.py`: illustration of using type hints with a
    user-defined class with errors.

source-code/typing/dict_correct.py

@@ -2,22 +2,22 @@
 
 import re
 import sys
-from typing import Dict
 
 
-def word_count(text: str) -> Dict[str, int]:
-    counts = dict() # type: Dict[str, int]
-    words = re.split(r'\W+', text)
+def word_count(text: str) -> dict[str, int]:
+    counts: dict[str, int] = {}
+    words = re.split(r"\W+", text)
     for word in words:
         word = word.lower()
         if word not in counts:
             counts[word] = 0
         counts[word] += 1
     return counts
 
-if __name__ == '__main__':
-    text = ' '.join(sys.stdin.readlines())
+
+if __name__ == "__main__":
+    text = " ".join(sys.stdin.readlines())
     counts = word_count(text)
     for word, count in counts.items():
         if word:
-            print(f'{word}: {count}')
+            print(f"{word}: {count}")

source-code/typing/dict_incorrect_01.py

@@ -2,26 +2,26 @@
 
 import re
 import sys
-from typing import Dict
 
 
-def word_count(text: str) -> Dict[str, int]:
-    counts = dict() # type: Dict[str, int]
-    words = re.split(r'\W+', text)
+def word_count(text: str) -> dict[str, int]:
+    counts: dict[str, int] = {}
+    words = re.split(r"\W+", text)
     nr_words = 0
     for word in words:
         word = word.lower()
         if word not in counts:
             counts[word] = 0
         counts[word] += 1
         nr_words += 1
-    nr_words -= counts.pop('')
+    nr_words -= counts.pop("")
     for word, count in counts.items():
         counts[word] /= nr_words
     return counts
 
-if __name__ == '__main__':
-    text = ' '.join(sys.stdin.readlines())
+
+if __name__ == "__main__":
+    text = " ".join(sys.stdin.readlines())
     counts = word_count(text)
     for word, count in counts.items():
-        print(f'{word}: {count}')
+        print(f"{word}: {count}")

source-code/typing/duck_typing_wrong.py renamed to source-code/typing/duck_typing_incorrect.py

@@ -20,7 +20,7 @@ def make_sound(self) -> None:
         print('ring-ring')
 
 
-def sound_repeater(sound_maker: SoundMaker, nr_repeats: int):
+def sound_repeater(sound_maker: SoundMaker, nr_repeats: int) -> None:
     for _ in range(nr_repeats):
         sound_maker.make_sound()
 

source-code/typing/typed_duck_typing.py

@@ -0,0 +1,46 @@
+#!/usr/bin/env python
+import argparse
+from typing import Protocol
+
+
+class SoundMaker(Protocol):
+
+    def make_sound(self) -> None:
+        pass
+
+
+class Duck:
+
+    def make_sound(self) -> None:
+        print('quack')
+
+
+class AlarmClock:
+
+    def make_sound(self) -> None:
+        print('ring-ring')
+
+
+def sound_maker_factory(sound_type: str) -> SoundMaker:
+    if sound_type == 'duck':
+        return Duck()
+    elif sound_type == 'alarm':
+        return AlarmClock()
+    else:
+        raise ValueError(f'unknown sound type: {sound_type}')
+
+
+def sound_repeater(sound_maker: SoundMaker, nr_repeats: int) -> None:
+    for _ in range(nr_repeats):
+        sound_maker.make_sound()
+
+
+if __name__ == '__main__':
+    arg_parser = argparse.ArgumentParser(description='sound maker')
+    arg_parser.add_argument('--type', choices=['duck', 'alarm'],
+                            help='sound source')
+    arg_parser.add_argument('--n', type=int, default=1,
+                            help='number of sounds to make')
+    options = arg_parser.parse_args()
+    sound_maker: SoundMaker = sound_maker_factory(options.type)
+    sound_repeater(sound_maker, options.n)

source-code/typing/typed_duck_typing_clean.py

@@ -20,7 +20,7 @@ def make_sound(self) -> None:
         print('ring-ring')
 
 
-def sound_repeater(sound_maker: SoundMaker, nr_repeats: int):
+def sound_repeater(sound_maker: SoundMaker, nr_repeats: int) -> None:
     for _ in range(nr_repeats):
         sound_maker.make_sound()
 

source-code/typing/typed_duck_typing_false_positive.py

@@ -20,7 +20,7 @@ def make_sound(self) -> None:
         print('ring-ring')
 
 
-def sound_repeater(sound_maker: SoundMaker, nr_repeats: int):
+def sound_repeater(sound_maker: SoundMaker, nr_repeats: int) -> None:
     for _ in range(nr_repeats):
         sound_maker.make_sound()