These go into the architecture/block of their scope and will be
used by component instantiations to make sure the bindings are
correct and complete.
Also handle signal declarations. The elaborator will use these
to generate module local variables that are used by the architecture.
Separate elaboration from code generation in the Entity, and add
to Architectures a code generator to handle some simple cases. At
this point we have the basic structure for the VHDL compiler.
Elaboration will need a parse tree for expressions. Create one for
the expression types that are currently supported. Also add rules
and the keywords for all the remaining binary logical operators.
Stephen Williams