How does defining functions within functions in PHP impact code readability and maintainability?

Defining functions within functions in PHP can impact code readability and maintainability by making the code more complex and harder to follow. It can also lead to potential naming conflicts and make it difficult to reuse or test the inner functions independently. To improve readability and maintainability, it's recommended to define functions outside of other functions and use proper naming conventions.

// Define inner functions outside of the main function for better readability and maintainability

function outerFunction() {
    innerFunction();
}

function innerFunction() {
    // Inner function logic
}

// Call the outer function
outerFunction();