CVS difference for ai12s/ai12-0025-1.txt

Differences between 1.4 and version 1.5
Log of other versions for file ai12s/ai12-0025-1.txt

--- ai12s/ai12-0025-1.txt	2013/11/01 04:20:41	1.4
+++ ai12s/ai12-0025-1.txt	2013/11/02 00:05:20	1.5
@@ -2877,6 +2877,15 @@
+From: Tucker Taft
+Sent: Thursday, October 31, 2013  4:34 PM
+Thanks for the interesting set of data.
+Glad to hear that you were able to solve your problem using an existing portable
 From: Randy Brukardt
 Sent: Thursday, October 31, 2013  6:01 PM
@@ -2946,5 +2955,40 @@
 anonymous array of anonymous access-to-subprogram used as an in parameter would
 have the same special semantics. But that's pretty weird - but it might make a
 sensible alternative to 'Unchecked_Access.
+From: Erhard Ploedereder
+Sent: Friday, November  1, 2013  2:29 PM
+> Actually, I hadn't considered this, as I wouldn't have expected that 
+> passing in an in-mode array of anonymous access-to-subprogram 
+> parameter would be different than passing in a bunch of anonymous 
+> access-to-subprogram parameters.
+Big difference, really. As soon as subprogram values or references are
+assignable, all hell breaks loose wrt safety of up-level addressing local
+variables. Only parameter passing is safe in this regard.
+(I trust that there isn't some funny trick around to assign values of
+anonymous subprogram access type, or else Randy's remark does not hold that
+they are equivalent to subprogram parameters.)
+From: Randy Brukardt
+Sent: Friday, November  1, 2013  2:44 PM
+Anonymous access-to-subprogram parameters have infinitely deep accessibility,
+so the accessibility check fails on any attempt to assign them to some other
+kind of access-to-subprogram type (including anonymous access-to-subprogram
+components and objects).
+Since we don't have 'Unchecked_Access for subprograms ("There's a hole in the
+bucket, a hole." :-) the only ways to assign such values involve Chapter
+13 tricks (unchecked conversion, overlays, etc.), and no one ought to expect 
+hose to work portably. So these are safe and we don't have to make an
+accessibility check on the 'Access.

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