Entity generics are easily implemented as module parameters, so make
it so. Give the parameters their default values from the generic declaration.
Array bounds may use values that cannot be evaluated right away, so
put off their evaluation.
Named libraries are similar to the work library, but they are not
written to implicitly, or imported implicitly. They are only brought
in by a "library" clause, the the packages within the library are
brought in by a "use" clause.
Instead of using automatic variables for global
types, I allocate them dynamically. Thanks to it,
all type objects can be treated in the same way,
as all of them are pointers allocated with `new'.
Now we will be able to remove all scopes in the same
manner, no matter if it is a global or local scope,
by deleting all carried pointers.
When a "use" clause tries to pull a package from the work library,
put together a file name and try to find that package in the
work library directory. If found, parse the package file and
try again to find the package.
Build up a work library by writing a VHDL representation of the
package header into a source file. This representation needs to
be accurate enough that later invocations of vhdlpp can read them
with the VHDL parser.
Significant rework of scope management to unify the handling of
types in the ieee library and types/constants/components in packages.
This involved adjusting the parser rules to manage a stack of scopes
and rewriting the IEEE library support to not use global maps for
the loaded types.
This creates the Package class to represent packages, and the
Scope class to represent scopes in general. The library functions
are worked up to support scanning scopes for declarations that are
imported by "use" clauses.
Stephen Williams
Pawel Szostek