Function Block binding in Swift

Block binding in Swift is used to declare a constant or a variable in a specific scope. It allows you to limit the scope of a constant or variable so that it can only be accessed within a particular section of code.

Here is an example of using block binding with a constant:

func printMessage() {
    let message = "Hello World!"
    print(message)
}
printMessage()   // Output: "Hello World!"
print(message)    // Throws an error since message cannot be accessed outside of the function's scope

In this example, the constant message is only accessible within the printMessage() function.

Here is an example of using block binding with a variable:

func increaseCount() {
    var count = 0
    count += 1
    print("Count: \(count)")
}
increaseCount()   // Output: "Count: 1"
increaseCount()   // Output: "Count: 1"

In this example, the variable count is only accessible within the increaseCount() function. Every time the function is called, a new instance of the variable count is created and initialized to 0.

Block binding can also be used with control flow statements in Swift such as if, for, and while loops. Here is an example using block binding with a for loop:

let numbers = [1, 2, 3, 4, 5]
var sum = 0
for num in numbers {
    sum += num
}
print("Sum: \(sum)")   // Output: "Sum: 15"

In this example, the variable num is only accessible within the scope of the for loop. It is initialized to the value of the current element in the numbers array during each iteration of the loop.