RE: [sv-bc] $onehot(), $bits() and $signed() of streaming concatenations

Brad,

For context, it may be helpful to see the threads beginning with

http://www.eda.org/sv-ac/hm/9764.html
http://www.eda.org/sv-ac/hm/9765.html
http://www.eda.org/sv-ac/hm/9791.html
http://www.eda.org/sv-ac/hm/9793.html

It is not clear to me, for example, that

So for $onehot() it's clear that you can legally call

     $onehot({>>{x,y,z}})

Regards,
Shalom

From: owner-sv-bc@eda.org [mailto:owner-sv-bc@eda.org] On Behalf Of Brad Pierce
Sent: Friday, October 21, 2011 1:47 AM
To: sv-bc@eda.org
Subject: RE: [sv-bc] $onehot(), $bits() and $signed() of streaming concatenations

> in such a context

I meant "in an assignment-like context".

---
When 11.4.14 says that a streaming_concatenation, such as, {>>{x,y,z}}, can be used "as the target of an assignment, or as the source of an assignment", I take that to mean that in an assignment-like context it's not "an operand in an expression" and that it can be used without "first casting it to a bit-stream type".
For example, if a streaming_concatenation is the actual input argument of a subroutine call and it's passed by value to a formal input argument of a bit-stream type, then the streaming_concatenation actual is being legally assigned to the formal with no need for a static cast.
     f({>>{x,y,z}}, ...)
What though about calls to LRM-defined $-functions that are polymorphic, such as $onehot(), $bits() and $signed()?
Mantis 2476 (http://www.eda-stds.org/mantis/view.php?id=2476) clarifies that the argument to $onehot() can be anything of bit-stream type, and that, if the argument is "expression", then "For the purpose of calculating the return value, the argument is treated as a vector of equal size assigned from {>>{expression}} (see 11.4.14)."
So for $onehot() it's clear that you can legally call
     $onehot({>>{x,y,z}})
But what about $bits() and $signed()? It seems to me that it should be legal to call them, too, with a streaming_concatenation argument, but that's not so clear in the LRM, as far as I can tell.
-- Brad
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