Revised analysis of IR1070

Folks,

I had an action from months ago to revise my analysis of IR2070. Please find
the revised analysis attached. To refresh your memory, the notes from the
telecon where we discussed it are:

TOPIC: IR 1070 VPI Issue 14 -- Prefixes in USE clauses

The issue concerns legality of a package, pkg, that contains a type
named "work" along with

use work.pkg.all,work.definework;

The issue is whether work.definework is legal here because of the
possibility that "work" now refers to the type in the package.

Peter's initial analysis was that the example is legal because the
visibility associated with the use clause takes effect at the end of
the use clause.  However, this analysis implies that

use work.pkg.all;
use work.definework;

would be illegal. Chuck argued that the second example is also
legal. The clause use.work.pkg.all makes the type "work" potentially
visible. However, it does not become directly visible because the type
"work" is a homograph of the visible library name "work".

Discussion also revealed some issues with clause 11.2, Design libraries.

The LRM states: "...each logical name defined by the library clause is
directly visible, except where hidden in an inner declarative region
by a homograph of the logical name according the the rules of 10.3"

10.3 defines "homograph", but 10.4 gives the rules for USE clauses, so
it probably makes sense to refer to both 10.3 and 10.4.

Also, homographs apply only to declarations and library names are not
(technically) declarations. Wording should be added to treat library
logical names as declarations for purposes of overload resolution.

ACTION: Peter to revise his analysis.

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
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