title: initialize string pointer in struct
body: <p>Go Newbie question: I am trying to init the following struct, with a default value. I know that it works if "Uri" is a string and not pointer to a string (*string). But i need this pointer for comparing two  instances of the struct, where Uri would be nil if not set, e.g. when i demarshal content from a json file. But how can I initialize such a struct  properly as a "static default"?</p>
  
  <pre><code>type Config struct {
    Uri       *string
  }
  
  func init() {
    var config = Config{ Uri: "my:default" }
  }
  </code></pre>
  
  <p>The code above fails with</p>
  
  <pre><code>cannot use "string" (type string) as type *string in field value
  </code></pre>