title: What's the point of one-way channels in Go?
body: <p>I'm learning Go and so far very impressed with it.  I've read all the online docs at golang.org and am halfway through Chrisnall's "The Go Programming Language Phrasebook".  I get the concept of channels and think that they will be extremely useful.  However, I must have missed something important along the way, as I can't see the point to one-way channels.</p>
  
  <p>If I'm interpreting them correctly, a read-only channel can only be received on and a write-only channel can only be transmitted on, so why have a channel that you can send to and never receive on?  Can they be cast from one "direction" to the other?  If so, again, what's the point if there's no actual constraint?  Are they nothing more than a hint to client code of the channel's purpose?</p>