Interface

An interface reveals portions of a module to the outside world so that clients can access functionality of modules. All declarations in an interface are visible to clients of a module.

Each interface usually takes the form of a file with a ".i3" extension, and have the following format:

INTERFACE interface-name;

IMPORT imported-interfaces;

  Declarations;
     ...
  Declarations;

END interface-name.

Generally, interface-name is the same as the name of the module that exports this interface. For example, a CDROM module exports a CDROM interface.

Example

Here is an example of an interface for a module Thing contained in a file called Thing.i3:

INTERFACE Thing;
(* Thing does not need to import any other interfaces, hence no IMPORT clause. *)

CONST MaxEntries = 53;
TYPE T = RECORD name: TEXT; size: INTEGER END;

PROCEDURE Print(r: T);
PROCEDURE Make(n: TEXT; s: INTEGER): T;

END Thing.