etcetc

let d1 = ["a":"foo","b":"bar"]
let d2 = ["c":"car","d":"door"]

let d3 = d1.reduce(d2) { (var d, p) in
    d[p.0] = p.1
    return d
}

/* Result is ["b": "bar", "a": "foo", "d": "door", "c": "car"] */

etcetc

<!-- 
  This gist is just an exploration of various types of scopes on a directive.  I had mistakenly thought that 
  an isolate scope is a mechanism for selectively passing elements in the directive scope to the scope.  So for example
  if a parameter "p1" was defined in the outer scope of a directive, you could name it in the isolated scope and it 
  would be incorporated into the directive scope.  However, this only applies to attributes that are on the directive itself
  and not parameters that are in the scope at large.

  If we use the "@", we are just bringing in the string assocaited with the attribute
  If we use the "=", we are using the attribute value as a reference, and essentially evaluating it.  This enables us 
  to watch that parameter for changes.  It doesn't make any sense to "watch" a parameter that was brought in using "2" because it's value will never change - it's just a string