RE: ISAC: minutes from meeting on 07 February 2008

Chuck,

I think you've certainly hit the nail on the head when you say we use the
term "context" rather loosely. A search of the 1076-2002 PDF reveals 70
occurrences of the word "context". Many of them mean innermost complete
context, but many others simply mean "syntactic place." A number of
occurrences also refer to the context clause of a design unit and the
context items in a context clause.

In your proposed changes, I'm not comfortable with the form of words,
"without using any other information from the <whatever>". The <whatever>
isn't an information provider; rather, it is a thing that has properties
that we might consider but want to exclude in certain cases.

I think what we're trying to say is that we want a discrete range or
expression to be considered as a "complete context" for the purposes of
application of the rules of 10.5, modulo some conditions in each case. The
term "complete context" is defined in 10.5.

Perhaps we might say something like the following:

In 3.2.1.1: "For a discrete range used in a constrained array definition
... Otherwise, both bounds must be of the same discrete type, other
than universal_integer; this type must be determined by applying the
rules of Clause 10.5 to each bound considered as a complete context, using
the fact that the type must be discrete and that both bounds must have the
same type...."

In 7.3.5: "The target type of a type conversion is the base type of the type
mark. The type of the operand of a type conversion must be
determinable by applying the rules of Clause 10.5 to the operand
as a complete context. (In particular, the type of the operand must be
determinable independent of the target type)..."

And similarly for the remaining cases. This would require modifying the text
in 10.5 to allow certain constructs specified elsewhere (e.g., in the
abovementioned subclauses) to be considered as a complete construct. A
possible form of words: after "a complete context is either a declaration, a
specification, or a statement", add "In certain cases, a discrete range or
an expression is also considered to be a complete context."

Given the loose usage of the word "context" elsewhere in the LRM, should we
consider clarifying other occurrences?

Cheers,

PA

--
Dr. Peter J. Ashenden         peter@ashenden.com.au
Ashenden Designs Pty. Ltd.    www.ashenden.com.au
PO Box 640                    VoIP: sip://0871270078@sip.internode.on.net
Stirling, SA 5152             Phone: +61 8 7127 0078
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> -----Original Message-----
> From: owner-isac@server.eda.org 
> [mailto:owner-isac@server.eda.org] On Behalf Of Chuck Swart - MTI
> Sent: Friday, 8 February 2008 16:47
> To: isac@server.eda.org
> Subject: ISAC: minutes from meeting on 07 February 2008
> 
> 
> These are also available at the website.
> I am also attaching (a very slightly revised version of) IR 
> 2128 which 
> you need to vote on.
> 
> -- 
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