if-let operator syntax using flatmap

if let quickER.md

infix operator ?= {  precedence 90 }

func ?= <T> (inout f: T, optional:T?){
    let _  = optional.flatMap{f = $0}
}

Usage looks like:

store.name ?= json["name"]?.string

Replaces this:

if let name = json["name"]?.string{
    store.name = name
}