# Interfaces

An interface has the form:

        INTERFACE id;
          Imports;
          Decls
        END id.

where `id` is an identifier that names the interface, `Imports` is a sequence of import statements, and `Decls` is a sequence of declarations that contains no procedure bodies or non-constant variable initializations. The names declared in `Decls` and the visible imported names must be distinct. It is a static error for two or more interfaces to form an import cycle.

    Last modified on Wed Apr  3 09:39:04 PST 1996 by heydon
         modified on Mon Apr 18 14:04:10 PDT 1994 by kalsow