Re: [myhdl-list] How to make MyHDL Object-Oriented

[Christopher L. <loz...@fr...>]

Jan Decaluwe wrote:

    Coupling a sensitivity list to a module makes no sense.

Understood.  Here is the source of my confusion.

The manual says:

    Hardware descriptions need to support the concepts of module
    instantiation and hierarchy. In MyHDL, an instance (of a hardware
    module) is recursively defined as being either a sequence of
    instances, or a generator.

There are really two concepts here.   One is a high level module which
is recursively represented by a sequence of submodules.  And the other
is a leaf module which is represented by a generator.  Ports can be
associated with both high and low level modules   The logic,  generator 
and sensitivity lists are only associated with the leaf module.  Or we
could call them atomic and compound hardware modules.

Did I get that correct?   If so, thanks Jan for clearing that up for me. 

Accordingly I have updated split the Hardware Module class definition in
two here:

wiki.myhdlclass.com:8080/OOHDL

But that still does not solve all my problems for these classes. Back to
the Manual.

    The clock driver function ClkDriver() has a clock signal as its
    parameter. This is how a /port/ is modeled in MyHDL.


In the page on Atomic and Compound Hardware modules, I model ports as
public instance variables.  And internal signals as private instance
variables.    It is how experienced python developers expect to see
things.  It is natural for us to think of ports as instance variables. 
Then you can get inheritance of ports for  free as Hardware Modules are
subclassed.  The port methods automatically remove Children and Parents
from the instance variable list.  With this design, one would not have
to list all the ports repeatedly in the generator function for each
subclass.  They just get inherited.  Brings us a step closer towards
rich libraries of hardware modules that can be subclassed.  Cool! 

But there is a problem, as that is not how MyHDL models ports.  It is
not just an implementation problem.  It is a conflict between how
experienced Python developers see the world, and the functional approach
favored by experienced hardware engineers. 

-- 
Regards
Christopher Lozinski

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Expect a paradigm shift.
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