## 9.6 Ports

The module `Port` contains procedures operating on ports.

`IsPort`

  > `{Port.is` `+X``` `?B``}`

  tests whether `X` is a port.

`NewPort`

  > `{Port.new` `Xs``` `?Port``}`

  returns a new port pointing to the stream `Xs`.

`Send`

  > `{Port.send` `+Port``` `X``}`

  sends `X` to the port `Port`: The stream pointed to by `Port` is unified with `X``|_` (in a newly created thread), and the pointer advances to the stream's new tail.

`SendRecv`

  > `{Port.sendRecv` `+Port``` `X``` `Y``}`

  sends the pair `X``#``Y` to the port `Port`: The stream pointed to by `Port` is unified with `X``#``Y``|_` (in a newly created thread), and the pointer advances to the stream's new tail.

  The argument `X` is commonly used as message to be sent, while `Y` serves as reply to that message.