RE: [sv-bc] Serious issue with default expressions for task and function arguments

From: Mark Hartoog <Mark.Hartoog_at_.....>
Date: Fri Mar 04 2005 - 13:10:52 PST
Gordon Vreugdenhil wrote:
> Mark Hartoog wrote:
> [...]
> > My opinion is that engineers are not language experts, and giving an 
> > error when there is any ambiguity in what the default value expression
> > means is ok. I would just like to point out that the other languages
> > with this feature do not have things like hierarchical functional calls
> > or interface function calls, which make this issue more complicated. 
> 
> 
> Mark, the problem with this approach is that we're defining
> a *standard*.  If you really want to permit ambiguity and room
> for interpretation, fine, define the minimal required situations
> in which something is guaranteed to have known behavior and
> then add language for the remainder to the effect that "implementations
> may choose....".  Then it is clear to the users AND the implementors
> what the base standard behavior is that one can rely on.

That is not what I meant at all. 

Some knowledgeable people seem to expect default value expressions to be
evaluated in caller context. Other knowledgeable people expect default
value expressions to be evaluated in the function/task declaration 
context. 

Given this disagreement between knowledgeable people, we could simple vote
and pick one by majority vote on the committee, or we could say that if 
it is not obvious to us, then it will not be obvious to users either, and
change the *standard* to say that any case were these two interpretations 
might give different answers is illegal. 

Mark Hartoog
700 E. Middlefield Road
Mountain View, CA 94043
650 584-5404
markh@synopsys.com 
Received on Fri Mar 4 13:10:57 2005

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