anchor.diff:    /// `withNack` allows client-server protocols that do require the server to be
     /// notified when the client aborts the transaction to be encapsulated as
     /// selective operations.  The negative acknowledgment alternative will be
  -  /// available for picking in case some other instantiated alternative involved
  -  /// in the choice is committed to instead.
  +  /// available in case some other instantiated alternative involved in the
  +  /// choice is committed to instead.
     ///
     /// Like `guard`, `withNack` is typically used to encapsulate the client side
     /// operation of a concurrent protocol.  The client side operation typically
     /// constructs a request, containing the negative acknowledgment alternative,
     /// sends it to a server and then returns an alternative that waits for a
     /// rendezvous with the server.  In case the client later commits to some
  -  /// other alternative, the negative acknowledgment token becomes pickable and
  +  /// other alternative, the negative acknowledgment token becomes available and
     /// the server can also abort the operation.
     ///
     /// Here is a simple example of an operation encapsulated using `withNack`.
  
positive.code: /// infix operators into scope.
  module Infixes =
    /// Creates an alternative that, at instantiation time, offers to give the
    /// given value on the given channel, and becomes available for picking when
    /// another job offers to take the value.  `xCh <-? x` is equivalent to
    /// `Ch.Alt.give xCh x`.
    val inline (<--): Ch<'x> -> 'x -> Alt<unit>
  
    /// Creates a job that sends a value to another job on the given channel.  A
  
negative.code:   /// usage leads to undefined behavior.  See also `fill`.
    val inline fillFailure: IVar<'x> -> exn -> Job<unit>
  
    /// Creates an alternative that becomes available after the write once
    /// variable has been written to.
    val inline read: IVar<'x> -> Alt<'x>
  
  ////////////////////////////////////////////////////////////////////////////////
  