CVS difference for ai12s/ai12-0221-1.txt

Differences between 1.1 and version 1.2
Log of other versions for file ai12s/ai12-0221-1.txt

--- ai12s/ai12-0221-1.txt	2017/04/11 05:21:54	1.1
+++ ai12s/ai12-0221-1.txt	2017/04/21 05:43:53	1.2
@@ -193,3 +193,67 @@
 message. ;-)
 
 ****************************************************************
+
+From: John Barnes
+Sent: Tuesday, April 11, 2017  4:17 AM
+
+Looking in my attic I find:
+
+Preliminary Green (April 78) says (page 37)
+
+For in parameters, the parameter definition  may also include a specification
+of an expression that is implicitly assigned to the parameter if no explicit
+value is given in the call.
+
+
+Green (March 79) says (page 6-3)
+
+Exactly same as for Preliminary Green
+
+
+Preliminary Ada (June 1979) says (page 6-3)
+
+For in parameters, the parameter declaration  may also include a specification
+of a default expression, whose value is implicitly assigned to the parameter
+if no explicit value is given in the call.
+
+
+Ada (July 1980) says (page 6-3) nothing about defaults at all. That section
+was rewritten to rant about passing mechanisms. However, a new section 6.4.2
+on page 6-7 says
+
+If a subprogram declaration specifies a default value for an in parameter,
+then the corresponding parameter may be omitted from a call.
+
+====
+
+So it looks as if in out parameters could never have defaults.
+
+****************************************************************
+
+From: Bob Duff
+Sent: Tuesday, April 11, 2017  9:28 AM
+
+> So it looks as if in out parameters could never have defaults.
+
+I remember being disappointed when that feature was removed.
+I suppose I must be imagining things.
+
+****************************************************************
+
+From: Randy Brukardt
+Sent: Tuesday, April 11, 2017  2:46 PM
+
+...
+> Ada (July 1980) says (page 6-3) nothing about defaults at all. That 
+> section was rewritten to rant about passing mechanisms.
+
+The second paragraph on page 6-2 includes If the parameter declaration has
+mode in, and only then, it may include an initialization.
+
+Unless there is a difference between the first and second printing (the
+copy I have says it is from a second printing of November 1980), I'd expect
+that you'd find the rule there in your copy as well. Probably it moved to 6.1
+(where it remains today) between Preliminary Ada and original Ada.
+
+****************************************************************

Questions? Ask the ACAA Technical Agent