Is there no default(T) in Swift?

Question

I'm trying to port the Matrix example from Swift book to be generic.

Here's what I got so far:

struct Matrix<T> {
    let rows: Int, columns: Int
    var grid: T[]

    init(rows: Int, columns: Int, repeatedValue: T) {
        self.rows = rows
        self.columns = columns

        grid = Array(count: rows * columns, repeatedValue: repeatedValue)
    }

    func indexIsValidForRow(row: Int, column: Int) -> Bool {
        return row >= 0 && row < rows && column >= 0 && column < columns
    }

    subscript(row: Int, column: Int) -> T {
        get {
            assert(indexIsValidForRow(row, column: column), "Index out of range")
            return grid[(row * columns) + column]
        }
        set {
            assert(indexIsValidForRow(row, column: column), "Index out of range")
            grid[(row * columns) + column] = newValue
        }
    }
}

Note that I had to pass repeatedValue: T to the constructor.

In C#, I would have just used default(T) which would be 0 for numbers, false for booleans and null for reference types. I understand that Swift doesn't allow nil on non-optional types but I'm still curious if passing an explicit parameter is the only way, or if I there is some equivalent of default(T) there.

Answer 1

There isn't. Swift forces you to specify the default value, just like then you handle variables and fields. The only case where Swift has a concept of default value is for optional types, where it's nil (Optional.None).