where.swift

import UIKit


enum MyError: ErrorType {
    case Oooggh(String)
}

func errorProne() throws {
    throw MyError.Oooggh("nope")
}

do {
    try errorProne()
} catch MyError.Oooggh("agree") {
    // not match "agree" != "nope"
} catch MyError.Oooggh("nope") {
    print("nope")
}

var value = (1,2)
switch value {
case let (1, y):
    // match 1
    break
case let (x, y) where x / 5 == 1:
    // not-match
    break
default:
    break
}