Re: [myhdl-list] Small buglet

[Jan D. <ja...@ja...>]

Thomas Heller wrote:
> While working with Python generators in a testbench to supply test data to my instances,
> I found that the myhdl.instances() function not only returns MyHDL instances but also
> these generators.

Right. Sometimes I think that myhdl.instances() is a result
of me trying to be too clever, and therefore not really a good
idea. Suppose it would be required to always return instances
explicitly, would anyone have missed it?

Anyway. I think that you expect that the function only finds
instances created by the MyHDL decorators @instance, @always
and @always_comb (and also the "hierarchical" instances of
course.) Those decorators could return special objects that
can be easily be looked up by type. That's indeed what currently
happens with @always and @always_comb - but not with
@instance, which creates a generator directly.

Before 0.5, MyHDL had no decorators and the only option was
to use generators directly. Therefore, it was not possible
to differentiate between "MyHDL" generators and other ones.
At this point, myhdl.instances() is still compatible with
that behavior.

In the future, I believe the function should be modified
so that it works like you expect. It's a good idea to
require using MyHDL decorators for instances. The code
becomes clearer, and as you say, plain generators have
other uses, also in MyHDL code.

In the mean time, returning instances explicitly is a good
workaround. Perhaps better than the "feature" :-)

Feedback welcome.

Jan

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