How can I handle different types using generic type in swift?

Question

I\'m trying to write a class which allows me to easily interpolate between two values.

class Interpolation
{
    class func interpolate(from: T, to: T,          


        

Answer 1

It would be nice if you use Protocol to scale your generic type.

protocol Interpolate {
    associatedtype T
    static func interpolate(from: T, to: T, progress: CGFloat) -> T
}

Then let CGRect extension conform to your protocol:

extension CGRect: Interpolate {
    typealias T = CGRect
    static func interpolate(from: T, to: T, progress: CGFloat) -> CGRect.T {
        var returnRect = CGRect()
        returnRect.origin.x     = from.origin.x + (to.origin.x-from.origin.x) * progress
        returnRect.origin.y     = from.origin.y + (to.origin.y-from.origin.y) * progress
        returnRect.size.width   = from.size.width + (to.size.width-from.size.width) * progress
        returnRect.size.height  = from.size.height + (to.size.height-from.size.height) * progress
        return returnRect
    }
}

var from = CGRect(x: 0, y: 0, width: 1, height: 1) // (0, 0, 1, 1)
var to = CGRect(x: 1, y: 1, width: 0, height: 0)   // (1, 1, 0, 0)

CGRect.interpolate(from, to: to, progress: 1)      // (1, 1, 0, 0)

Also, this would make NSString conform to protocol Interpolate easily, like:

extension NSString: Interpolate {
    typealias T = NSString
    static func interpolate(from: T, to: T, progress: CGFloat) -> NSString.T {
        //...
        return "" 
    }
}