153 lines
3.0 KiB
Markdown
153 lines
3.0 KiB
Markdown
---
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marp: true
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paginate: true
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# class: invert
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theme: rose-pine
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footer: Tutorium 14 - 02.02.2024 - Nils Pukropp - https://s.narl.io/s/tutorium-14
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header:
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math: mathjax
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---
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# Tutorium 14 - 02.02.2024
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Decorator, Testing
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---
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# Decorator
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- **Design-Pattern**, oft auch **Wrapper** genannt
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- Verpackt ein Objekt um **zusätzliche Funktionalität** zu bieten
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- Funktionen sind auch Objekte
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- eine Klasse ist ein Objekt
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- Oft einfach **syntax sugar**
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---
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## Beispiel - execute_two_times
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```python
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def execute_two_times(fn: Callable[..., Any]) -> Callable[..., Any]:
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def wrapper(*args, **kwargs)
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fn(*args, **kwargs)
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fn(*args, **kwargs)
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return wrapper
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return wrapper
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@execute_two_times()
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def print_two_times(msg: str):
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print(msg)
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print_two_times("hello") # hello
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# hello
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```
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---
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## Beispiel - execute_by
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```python
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def execute_by(n: int):
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def wrapper(fn):
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def wrapped_fn(*args, **kwargs):
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for _ in range(0, n):
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fn(*args, **kwargs)
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return wrapped_fn
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return wrapped_fn
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return wrapper
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@execute_by(10)
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def print_ten_times(msg: str):
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print(msg)
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print_ten_times("hello") # hello
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# hello
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# ... (10 mal)
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```
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---
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## Beispiel - CommandExecutor
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```python
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class CommandExecutor[R]:
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def __init__(self):
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self.__commands: dict[str, Callable[..., R]] = {}
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```
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---
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## Beispiel - run
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```python
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def run(self, name: str, *args, **kwargs) -> list[R]:
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results : list[R] = []
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for command_name, command in self.__commands.items():
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if command_name == name:
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results += [command(*args, **kwargs)]
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return results
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```
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---
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## Beispiel - register
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```python
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def register(self, cmd: Callable[..., R]) -> Callable[..., R]:
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self.__commands[cmd.__name__] = cmd
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return cmd
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```
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---
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## Beispiel - CommandExecutor
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```python
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class CommandExecutor[R]:
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def __init__(self):
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self.__commands: dict[str, Callable[..., R]] = {}
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def run(self, name: str, *args, **kwargs) -> list[R]:
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results : list[R] = []
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for command_name, command in self.__commands.items():
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if command_name == name:
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results += [command(*args, **kwargs)]
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return results
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def register(self, cmd: Callable[..., R]) -> Callable[..., R]:
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self.__commands[cmd.__name__] = cmd
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return cmd
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```
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---
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## Beispiel - How to use
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```python
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app = CommandExecutor[str]()
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@app.register
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def hello_world() -> str:
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return 'hello_world'
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@app.register
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def divide(a: int, b: int) -> str:
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if b == 0:
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return "tried to divide by zero"
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return str(a / b)
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print(app.run('hello_world'))
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print(app.run('divide', 5, 0))
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print(app.run('divide', 10, 2))
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```
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---
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## Decorator in der Klausur
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- Waren noch nie Bestandteil der Klausur
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- Mut zur Lücke
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- Kann euch natürlich nichts versprechen
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---
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# Testing mit `pytest` |