!ASIS Issue #078
!topic  Corresponding_Base_Entity
!reference  ASIS 95-15.35
!from  Sergey Rybin 97-05-11
!keywords  Corresponding_Base_Entity
!discussion

How, do you think, what should be returned by
Asis.Declarations.Coresponding_Base_Entity in the following
situation:

procedure Renaming is
   type Rec1 is record
      I : Integer;
   end record;
   type Rec2 is record
      C : Rec1;
   end record;
   type Rec3 is record
      Comp : Rec2;
   end record;
   X : Rec3;
   Y : Rec3 renames X;
   Var1 : Rec2 renames Y.Comp;
   Var2 : Rec1 renames Var1.C;
   Var3 : Integer renames Var2.I;  -- << this is the declaration of interst
begin
   Var3 := 13;
end Renaming;

ASIS definition defines this query as follows:

--------------------------------------------
-- Section 15.35 function Coresponding_Base_Entity
--------------------------------------------

   function Coresponding_Base_Entity (Declaration : in Asis.Declaration)
                 return Asis.Expresion;

--------------------------------------------
-- Declaration - Specifies the rename declaration to query
--
-- Unwinds recursive renamings to return the expresion used to name
-- the first renamed entity that is not itself a renamed entity. This
-- expresion is the name expresion found in the last RENAME declaration
-- when folowing a chain of sucesive renaming declarations.
--
-- ...

But for the example above no name corresponding to the last renaming of
Var2.I can be found in any of the previous renamings. So, as we can
see, if in a renaming chain is some renaming of a *component* of some
*previously renamed* (record) object, we have a hole in the ASIS semantics.

Any comments?

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

    function Corresponding_Base_Entity (Declaration : in Asis.Declaration)
                                 return Asis.Expression;

---------------------------------------------------------------------------------------
-- Declaration - Specifies the rename declaration to query
--
-- The base entity is defined to be the renamed entity that is not itself 
-- defined by another renaming declaration.
--  
-- If the name following the reserved word "renames" is itself declared by a
-- previous renaming_declaration, then this query unwinds the renamings by
-- recursively operating on the previous renaming_declaration.
-- 
-- Otherwise, the name following the reserved word "renames" is returned.
--
-- Appropriate Declaration_Kinds:
--      An_Object_Renaming_Declaration
--      An_Exception_Renaming_Declaration
--      A_Procedure_Renaming_Declaration
--      A_Function_Renaming_Declaration
--      A_Package_Renaming_Declaration
--      A_Generic_Package_Renaming_Declaration
--      A_Generic_Procedure_Renaming_Declaration
--      A_Generic_Function_Renaming_Declaration
--
-- Returns Element_Kinds:
--      An_Expression

Changes were made to ASIS version 2.0.N.