Async Ports (Dezyne Reference Manual)

10.5.3 Async Ports

An async port is a requires of builtin type dzn.async which is defined in the behavior of a component.

async-port
  ::= "requires" "dzn.async" async-parameter-list? identifier ";"
async-parameter-list
  ::= "(" async-parameter ("," async-parameter)* ")"
async-parameter
  ::= data-type identifier

For example:

requires dzn.async (int i) defer;

The builtin dzn.async interface can be represented like this:

namespace dzn
{
  interface async (formals)
  {
    in void req (formals);
    in void clr ();
    out void ack (formals);

    behavior
    {
      bool idle = true;
      [idle]
        {
          on req: idle = false;
          on clr: {}
        }
      [!idle]
        {
          on clr: idle = true;
          on inevitable: {ack; idle = true;}
        }
    }
  }
}

Note: The use of dzn.async is discouraged for new programs, it will be replaced by defer in version 2.16, see the “wip-defer” branch.