This example tests the %import directive and working with multiple modules.

Use 'lua runme.lua' to run a test.

Overview:

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The example defines 4 different extension modules--each wrapping

a separate C++ class.

base.i - Base class

foo.i - Foo class derived from Base

bar.i - Bar class derived from Base

spam.i - Spam class derived from Bar

Each module uses %import to refer to another module. For

example, the 'foo.i' module uses '%import base.i' to get

definitions for its base class.