RE: [sv-ac] question about classes as local variables in properties and sequences

Yes, I think so. Unless someone thinks that we should allow other types
also.
 
Manisha

________________________________

From: Eduard Cerny [mailto:Eduard.Cerny@synopsys.com] 
Sent: Tuesday, July 11, 2006 2:42 PM
To: Kulshrestha, Manisha
Cc: sv-ac@eda-stds.org
Subject: RE: [sv-ac] question about classes as local variables in
properties and sequences


Manisha,
 
would this fit as a proposal in on of the errata that you filed today?
 
ed
 


________________________________

	From: Kulshrestha, Manisha
[mailto:Manisha_Kulshrestha@mentor.com] 
	Sent: Tuesday, July 11, 2006 4:56 PM
	To: Eduard Cerny; sv-ac@eda-stds.org
	Subject: RE: [sv-ac] question about classes as local variables
in properties and sequences
	
	
	Hi Ed,
	 
	I think it would be fine to state it in the LRM that local
variables can be only of the same type as those that can be used in
boolean expressions.
	 
	Thanks.
	Manisha

________________________________

	From: Eduard Cerny [mailto:Eduard.Cerny@synopsys.com] 
	Sent: Tuesday, July 11, 2006 12:02 PM
	To: Kulshrestha, Manisha; sv-ac@eda-stds.org
	Subject: RE: [sv-ac] question about classes as local variables
in properties and sequences
	
	
	Hi Manisha,
	 
	my understanding woudl be that local variables can be only of
the same type as those that can be sampled in the boolean expressions.
That is, no class types. I suppose that we could extend it, so that a
call to new is implicit anytime an instance is to be created, like for
the integral types of local variables. That to me seems quite feasible.
Is it needed?
	The question is, what if a task in the property copies the
handle to some other global variable. Normally, the instance of a
variable created in a property thread disappears when the thread dies.
Should the instance be preserved in this case? Or would it allow only a
deep copy to a global variable of that class type?  Etc...
	 
	Best regards,
	ed


________________________________

		From: owner-sv-ac@eda-stds.org
[mailto:owner-sv-ac@eda-stds.org] On Behalf Of Kulshrestha, Manisha
		Sent: Tuesday, July 11, 2006 2:41 PM
		To: sv-ac@eda-stds.org
		Subject: [sv-ac] question about classes as local
variables in properties and sequences
		
		
		Hi All,
		 
		I have few questions regarding usage of classes in
assertions:
		 
		1. Currently LRM does not allow the boolean expressions
in assertions to have class as per section 17.4.1. But there is no
restriction on having a local variable as a class. So, is it allowed to
have a local variable of type class in the assertion expression ? 
		 
		2. Currently section 17.4.1 lists all the types which
are not allowed to be in the boolean expressions. What are the main
reasons for this restriction ? Is it mainly driven by sampling issues or
there are other issues ?
		 
		3. Consider the following example with a local variable
of type class (called myClass. myClass has a data member called myData):
		 
		sequence S;
		  myClass lv;
		 
		(a, lv = new()) ##1 ((seq1, lv.myData = 0) or (seq2,
lv.myData = 1)) ##1 (d, $display("value of myData is %b", lv.myData));
		 
		endsequence
		 
		As per LRM section 17.8, each branch of 'or' should have
its own copy of lv and assign to it. But here, there is only one 'new'
on lv so both the branches of 'or' will refer to the same local variable
(because lv behaves like a pointer).
		 
		Currently LRM does not clarify how copies of the
variables should be created in case of branching for classes and other
objects which behave like pointers. 
		 
		Any inputs ?
		 
		Thanks.
		Manisha