VHDL does not allow to specify the size of returned std_logic_vector,
whereas Verilog requires the size to be known in advance. The size of
the vector is determined by checking the type of expression used in the
return statement.
We need to elaborate expressions so that function calls in
expressions (i.e. ranges) get bound to their proper scope.
This binding is in turn used to emit package scopes. This
is particularly interesting for ports of entities.
Maciej Suminski
Cary R
Stephen Williams