Templates are multiplexed such that at least a part of a content description
of a higher order parent template is represented by a lower order child template,
and a desired source code is generated by performing instantiation from the lower
order child template, and by inputting the generated lower order child instance
into the higher order parent template to perform further instantiation. Accordingly,
the pattern of the content description that is being expanded as a source code
is made flexible, and it becomes possible to easily generate different source codes
by merely changing the lower order child template without a need of changing the
engine program used for instantiation.
