#### 14.9.2 Constructors and Accessors for Ports

The procedures in this section provide means for constructing ports, accessing the type of a port, and manipulating the state of a port.

procedure: make-port port-type state

  Returns a new port with type port-type and the given state. The port will be an input, output, or I/O port according to port-type.

procedure: port/type port

  Returns the port type of port.

procedure: port/state port

  Returns the state component of port.

procedure: set-port/state! port object

  Changes the state component of port to be object. Returns an unspecified value.

procedure: port/operation port symbol

  Equivalent to

      (port-type/operation (port/type port) symbol)

procedure: port/operation-names port

  Equivalent to

      (port-type/operation-names (port/type port))

procedure: make-eof-object input-port

  Returns an object that satisfies the predicate `eof-object?`. This is sometimes useful when building input ports.