The declare attributes define various program-generator options,
including classname, extends, implements, and imports.
The "import" option is used to insert an import statement in the
program generator file.
The "classname" option is used to explicitly define the class name
of the program generator. In general, you won't ever need to use
the classname option because by default the classname is derived
from the name of the output file on the command line.
The "extends" option is used to define the superclass of the
program generator. The default superclass is Object.
The "implements" option is used to specify an interface class
for the program generator.