Is there a way to write this if
/else if
/else
ladder as a switch statement?
let x: Any = "123"
if let s = x as? String {
useString(s)
}
else if let i = x as? Int {
useInt(i)
}
else if let b = x as? Bool {
useBool(b)
}
else {
fatalError()
}
Here's my attempt:
switch x {
case let s where s is String: useString(s)
case let i where i is Int: useInt(i)
case let b where b is Bool: useBool(b)
default: fatalError()
}
It successfully chooses the right path, but s
/i
/b
are still of type Any
. The is
check doesn't have any effect in casting them. This forces me to force cast with as!
before usage.
Is there a way to switch on the type, and bind it to a name, all in one switch
statement?
Sure, you can use the conditional casting pattern case let x as Type
:
let x: Any = "123"
switch x {
case let s as String:
print(s) //use s
case let i as Int:
print(i) //use i
case let b as Bool:
print(b) //use b
default:
fatalError()
}