Some extremely contrived examples using Swift 1.2 if-let bindings

OptionalBinding.swift

// OptionalBinding.swift
// as seen in http://nshipster.com/swift-1.2/
//
// (c) 2015 Nate Cook, licensed under the MIT license

let a: Int? = 10
let b: Int? = 5
let c: Int? = 3
let d: Int? = -2
let e: Int? = 0


// ----------------------------------------------------------
// Example 1: add a + b if both are greater than zero

// original
if let a = a {
    if a > 0 {
        if let b = b {
            if b > 0 {
                println("a + b = \(a + b)")
            }
        }
    }
}

// swift 1.2
if let a = a where a > 0, let b = b where b > 0 {
    println("a + b = \(a + b)")
}


// ----------------------------------------------------------
// Example 2: compute (a + b) / c if c does not equal zero

// original
if let a = a {
    if let b = b {
        if let c = c {
            if c != 0 {
                println("(a + b) / c = \((a + b) / c)")
            }
        }
    }
}

// swift 1.2
if let a = a, b = b, c = c where c != 0 {
    println("(a + b) / c = \((a + b) / c)")
}


// ----------------------------------------------------------
// Example 3: compute (a + b) / (c + d) if a > b and
// (c + d) does not equal zero

// original
if let a = a {
    if let b = b {
        if a > b {
            if let c = c {
                if let d = d {
                    if c + d != 0 {
                        println("(a + b) / (c + d) = \((a + b) / (c + d))")
                    }
                }
            }
        }
    }
}

// swift 1.2
if let a = a, b = b where a > b,
   let c = c, d = d where c + d != 0
{
    println("(a + b) / (c + d) = \((a + b) / (c + d))")
}