Swift Style

Using If/Guard-Case

Both if-case and guard-case are most valuable when used to bind associated values to variables. They allow you to reach inside an enumeration and access those values based on an enumeration’s specific cases:

enum Result<T> { case success(T), error(Error) }
guard case .success(let value) = result else { return } // yes
print(value)

When pattern matching, prefer the ~= operator to if-case and guard-case. The following statements perform identical tests, checking whether myValue falls within a range:

if range ~= myValue { print("success") } // yes
if case range = myValue { print("success") } // no

Of these, the first is readable and simple. The second, while logically identical, is ...