X'inhu d-decorators u kif tikteb wieħed?

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Accepted Answer

A **decorator** huwa funzjoni li **tħawwad funzjoni oħra** biex iżżid komportament, mingħajr ma tbiddel il-kowd tal-oriġinali. Tiġi applikata bil-sintassi `@decorator` fuq funzjoni — mod nadif biex iżżid cross-cutting concerns bħal logging, timing, caching, jew access control.

## Kif jaħdmu d-decorators

```python
def my_decorator(func):
    def wrapper(*args, **kwargs):       # wraps the original function
        print("before")
        result = func(*args, **kwargs)  # call the original
        print("after")
        return result
    return wrapper                       # return the wrapped version

@my_decorator
def greet(name):
    print(f"Hello {name}")

greet("Ann")
# Output: before / Hello Ann / after
```

Is-sintassi `@my_decorator` hija shorthand għal `greet = my_decorator(greet)` — tirrimpiazza `greet` bil-`wrapper`, li jrun kowd extra madwar il-qari oriġinali. Il-`*args, **kwargs` jagħmlu l-wrapper jaħdem għal kwalunkwe firma ta' funzjoni.

## Eżempju pratiku: timing

```python
import time, functools

def timed(func):
    @functools.wraps(func)        # preserves func's name/docstring (important!)
    def wrapper(*args, **kwargs):
        start = time.perf_counter()
        result = func(*args, **kwargs)
        print(f"{func.__name__} took {time.perf_counter() - start:.3f}s")
        return result
    return wrapper

@timed
def slow_task():
    time.sleep(1)
```

`@functools.wraps(func)` huwa importanti — mingħajr, il-funzjoni wrapped tieqaf il-ism u docstring oriġinali.

## Decorators b'argumenti

```python
def repeat(times):               # outer takes the decorator's argument
    def decorator(func):
        @functools.wraps(func)
        def wrapper(*args, **kwargs):
            for _ in range(times):
                func(*args, **kwargs)
        return wrapper
    return decorator

@repeat(times=3)
def hello(): print("hi")  # prints "hi" three times
```

A parameterized decorator jeħtieġ saff addizzjonali (funzjoni li tirrituri decorator).

## Decorators integrati / minn library

```text
@property            → turn a method into a computed attribute
@staticmethod / @classmethod → method types
@functools.lru_cache → memoize results
@app.route("/")      → web framework routing (Flask)
@pytest.fixture      → test fixtures
```

## Għaliex dan huwa importanti

Decorators huma feature b'enerġija u distinktivament-Pythonic għal **iżżid komportament riusabbli** (logging, timing, caching, authentication, validation, routing) għal funzjonijiet b'mod nadif u deklarattiv — separazzjoni ta' cross-cutting concerns mill-logika ewlenija.

Huma kif kullimkien fil-Python real: web frameworks (`@app.route`), caching (`@lru_cache`), klassijiet (`@property`), u testing.

L-għarfien kif tikteb (funzjoni wrapper, `*args/**kwargs`, `functools.wraps`) u l-forma parameterized tħallielek tużża d-decorators tal-ecosystem b'mod korrett u taqrx l-astrazzjonijiet ta' reusability tiegħek.