Channel types

Channels are similar to data types. Instead of relating a user-defined channel to built-in data, we relate them to a built-in channel types instead. The methods required for supporting the full functionality of a channel are operations necessary to send and receive data on the channel, rather than a read and write operation on a data value.

defchan e1of2 <: chan(bool) (bool d0,d1,e)
{
   spec {
    exclhi(d0,d1)
   }
}

Port lists for channel types can be data types (built-in or user-defined) or channels. Processes are not valid types for ports of a channel type.