Struct Chain Calls

StructChainCalls.swift

// Approach 1 - [https://stackoverflow.com/a/70492824/6576315]

struct Employee {
    
    var name: String?
    var designation: String?
    
    func name(_ name: String) -> Employee {
        .init(name: name, designation: self.designation)
    }
    
    func designation(_ designation: String) -> Employee {
        .init(name: self.name, designation: designation)
    }
}

// Approach 2 - https://stackoverflow.com/a/62350778/6576315

// Approach 3 - Dynamic Member Lookup

@dynamicMemberLookup
struct Setter<Subject> {
    let subject: Subject
    
    subscript<Value>(dynamicMember keyPath: WritableKeyPath<Subject, Value>) -> ((Value) -> Setter<Subject>) {
        
        var subject = self.subject
        
        return { value in
            subject[keyPath: keyPath] = value
            return Setter(subject: subject)
        }
    }
}

struct Employee {
    
    var name: String?
    var designation: String?
}

let emp = Setter(subject: Employee())
    .designation("iOS Engineer")
    .name("Speedy")
    .subject

print(emp.designation)