Swift 5.6: Combining Logical Operators

Let’s define some booleans first:

let enteredDoorCode = true
let passedRetinaScan = false
let hasDoorKey = false
let knowsOverridePassword = true

You can combine multiple logical operators to create longer compound expressions:

if enteredDoorCode && passedRetinaScan || hasDoorKey || knowsOverridePassword {
print(“Welcome!”)
} else {
print(“ACCESS DENIED”)
}

What do you think it would print? Keep you answer in mind

“Readability is always preferred over brevity; use parentheses where they help to make your intentions clear.”

Explicit Parentheses — for Clean Code
It’s sometimes useful to include parentheses when they’re not strictly needed, to make the intention of a complex expression easier to read. In the door access example above, it’s useful to add parentheses around the first part of the compound expression to make its intent explicit:

if (enteredDoorCode && passedRetinaScan) || hasDoorKey || knowsOverridePassword {
print(“Welcome!”)
} else {
print(“ACCESS DENIED”)
}

What do you think now that it would print?

Note
The Swift logical operators && and || are left-associative, meaning that compound expressions with multiple logical operators evaluate the leftmost subexpression first.

And … it prints “Welcome!”

Excerpts From
The Swift Programming Language (Swift 5.6)
Apple Inc.
https://books.apple.com/ro/book/the-swift-programming-language-swift-5-6/id881256329
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