!ASIS Issue #079
!topic  Corresponding_Called_Entity and stream oriented attribute references
!reference  ASIS 95-18.25 and 17.29
!from  Alain Le Guennec 97-04-25
!keywords  Corresponding_Called_Entity, Corresponding_Called_Function, stream attribute references
!discussion

As currently specified, Corresponding_Called_Entity and
Corresponding_Called_Function have to return a Nil_Element
for a prefix that denotes an attribute reference.

I think there is a case in Ada95 where these queries could
yield a more usefull result, namely for stream oriented attributes
which have an attribute representation clause.

Please consider the following example:
-------------------------------------
with Ada.Streams;
procedure Sample32 is

   package My_Package is
      type TR  is null record;

      procedure Write_TR (Stream : access Ada.Streams.Root_Stream_Type'Class;
			  Item   : in TR);
      for TR'Write use Write_TR;
   end My_Package;
   
   package body My_Package is
      procedure Write_TR (Stream : access Ada.Streams.Root_Stream_Type'Class;
			  Item   : in TR) is
      begin
	 null;
      end Write_TR;      
   end My_Package;

   use My_Package;

   type SA is access Ada.Streams.Root_Stream_Type'Class;

   R  : TR;
   S  : SA;
begin
   TR'Write (S, R);
end Sample32;

It is determined statically that this call is actually pointing to
My_Package.Write_TR, so why not return this subprogram declaration
instead of a Nil_Element ?

Any comment ?

!resolution  Accept, with Modification.
!date 97-05-28
!Notes

For 18.25, function Corresponding_Called_Entity, add the following
paragraph to the commentary:

-- If procedure_prefix denotes an attribute_reference, and if the
-- corresponding attribute is (re)defined by an attribute definition clause, an
-- implementation is encouraged, but not required, to return the definition of
-- the corresponding subprogram whose name is used after "use" in this
-- attribute definition clause. If an implementation cannot return such a
-- subprogram definition, a Nil_Element should be returned. For an attribute
-- reference which is not (re)defined by attribute definition clause, a
-- Nil_Element should be returned.

For 17.29, function Corresponding_Called_Function, add the following
paragraph to the commentary:

-- If function_prefix denotes an attribute_reference, and if the
-- corresponding attribute is (re)defined by an attribute definition clause, an
-- implementation is encouraged, but not required, to return the definition of
-- the corresponding subprogram whose name is used after "use" in this
-- attribute definition clause. If an implementation cannot return such a
-- subprogram definition, a Nil_Element should be returned. For an attribute
-- reference which is not (re)defined by attribute definition clause, a
-- Nil_Element should be returned.

Changes were made to ASIS version 2.0.N.