A module may refer to names defined in other modules with the aid of
use
and
import
declarations.
If a module is compiled before one or more of the modules to which it
refers, the resulting module object will be
incomplete.
An incomplete module is analogous to a object module (a
``.o file'' )
with undefined external references.
The
SDL linker
takes a set of incomplete modules that contain only references to each
other and to complete modules, and resolves the references.