🎁 Decorators

Decorators are functions that wrap other functions to extend or modify their behavior. They are built on higher-order functions and closures.

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✅ Basic Idea

def logger(func):
    def wrapper(*args, **kwargs):
        print(f"Calling {func.__name__}")
        return func(*args, **kwargs)
    return wrapper

@logger
def greet(name):
    return f"Hello, {name}!"

Calling greet("Alice") now prints a log and returns the greeting.

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✅ Why Decorators?

• Add logging or timing
• Validate inputs
• Cache results
• Enforce permissions

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✅ Using functools.wraps

To preserve the original function’s metadata (like __name__ and docstring):

from functools import wraps

def logger(func):
    @wraps(func)
    def wrapper(*args, **kwargs):
        print(f"Calling {func.__name__}")
        return func(*args, **kwargs)
    return wrapper

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🔍 Key Takeaways

• Decorators wrap functions to add behavior.
• They use higher-order functions and closures.
• @decorator is syntax sugar for func = decorator(func).

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Back to Closures