[myhdl-list] range object

[Haitao Z. <ha...@gm...>]

Another nice to have :)

In VHDL one could define a range type and define a constant with it,
so that one can associate a symbolic name say CTRL_FIELD with  7
DOWNTO 3, and then one can refer to register(CTRL_FIELD). In Verilog
one can probably get by with macro defines. However in Python the
native slicing is limited to integer arguments (?), so one has to
define two named constants instead of passing an indexing object.

This feature is handy when one needs to define control register
fields. It allows one to define the named constants in one place.

In Matlab one can index any vector with another vector. I don't see
why this shouldn't be doable in Python as well. Maybe just no need for
it, until the hardware designers come along? Is the simplest way to
overload __getslice__ to accept a tuple (defining range)?

I am not a Python expert so I will be happy to know if there is a way
to do it now in Python.

Haitao