INTERCAL Select Operator in Swift

INTERCAL Select.swift

// Learn more: http://en.wikipedia.org/wiki/INTERCAL#Operators

infix operator ~ {
    associativity left
    precedence 140
}

// Intercal select
func ~(var lhs: Int, var rhs: Int) -> Int {
    let lsb = 1
    var result = 0
    var foundCount = 0
    
    for i in 0..<sizeof(Int) {
        let search = rhs & lsb
        if lhs & lsb == search {
            result |= search << foundCount++
            rhs >>= 1
        }
        
        lhs >>= 1
    }
    
    return result
}

51 ~ 21 // -> 5
//    lhs: 51; 1  *1*  0  *0*  1  *1*
//    rhs: 21; 0   1   0  *1* *0* *1*
// result:  5; 0   0   0   1   0   1