title: What language is Swift written in?
body: <p>Well, like the title says, what language is <a href="https://en.wikipedia.org/wiki/Swift_(programming_language)">Swift</a> (<a href="https://en.wikipedia.org/wiki/Apple_Inc.">Apple</a>'s language, not the other Swift thing) written in?  More specifically, what is the compiler written in.  Is it written in <a href="https://en.wikipedia.org/wiki/C_(programming_language)">C</a> (like every other language) or some other magical, unknown-til-now Super Language?  Or is it some strange recursive, boot-strapped version of Swift?  The web is strangely quiet on this issue.</p>