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• Summary

Introduction

Aspectlib is a Python library for aspect-oriented programming (AOP) that provides a clean and easy way to separate cross-cutting concerns from the core logic of a program. AOP is a programming paradigm that aims to increase modularity and reduce code duplication by allowing for the separation of concerns.

Features

Aspectlib provides several key features for implementing AOP in Python:

• Support for function and method interception
• Support for context managers and decorators
• A flexible aspect composition system
• The ability to apply aspects selectively based on criteria such as function signature or module name

Examples

Here are some simple examples of using Aspectlib:

Logging

from aspectlib import Aspect, weave

def log_aspect(func):
    def wrapper(*args, **kwargs):
        print(f"Calling {func.__name__} with {args} and {kwargs}")
        result = func(*args, **kwargs)
        print(f"{func.__name__} returned {result}")
        return result
    return wrapper

class MyClass:
    @log_aspect
    def my_method(self, arg1, arg2):
        return arg1 + arg2

weave(aspects=[Aspect(log_aspect)], modules=[MyClass])
MyClass().my_method(1, 2) # Will print "Calling my_method with (1, 2) and {}" and "my_method returned 3"

Timing

from aspectlib import Aspect, weave
import time

def time_aspect(func):
    def wrapper(*args, **kwargs):
        start_time = time.time()
        result = func(*args, **kwargs)
        end_time = time.time()
        print(f"{func.__name__} took {end_time - start_time} seconds to run")
        return result
    return wrapper

@time_aspect
def my_function():
    time.sleep(1)

weave(aspects=[Aspect(time_aspect)], modules=[__name__])
my_function() # Will print "my_function took 1.000123 seconds to run"

This Python code demonstrates the use of the aspectlib library to time a function's execution.

First, the time_aspect function is defined as an aspect that takes a function as an argument and wraps it with additional timing functionality. The wrapper function is defined inside time_aspect, which records the start time, calls the original function, records the end time, and prints the elapsed time. The wrapper function then returns the result of the original function.