Re: [myhdl-list] understanding Signal and intbv

[Thomas H. <th...@ct...>]

Am 12.11.2010 11:18, schrieb Jan Decaluwe:
> Thomas Heller wrote:
>> I cannot find out how to split the bus into single bits (or parts)
>> so that I can connect them to instances.
[...]
>
> Short answer: in 0.7, you can use the Signal call interface
> to construct implicit signals that work as expected in structure.
>
> Longer answer:
>
> This is what I consider to be MyHDL's most important gotcha.
> In MyHDL 0.7, I introduce a solution called ShadowSignals - however
> be warned that it's not as intuitive as with compiled HDLs, where
> the meaning of slicing can be derived from the code context
> by a compiler.
>
> Background info starting point:
>
>      http://www.myhdl.org/doc/dev/whatsnew/0.7.html#shadow-signals
>
Thanks, Jan, for this answer.  0.7 seems to work as expected.
I have to believe you that it is a good decision to make ShadowSignals
readonly, but let me ask one question:

Why can't you use slicing/indexing notation to create a shadow signal?
Performance?  Backwards compatibility?  Education of the programmer?
Or is it simply not possible?

It seems a little error-prone having to use the call interface in one
case and the indexing notation in the other case.

Thanks,
Thomas