root/trunk/tendra/src/producers/ada/spec/SI99-0006-1.TXT

!standard 3.9.10                                  06-12-14  SI99-0006-1/03
!standard 3.9.11
!standard 3.9.15
!standard 15.51
!standard 16.19
!class binding interpretation 06-04-10
!status ARG Approved  8-0-1  06-06-09
!status work item 06-04-10
!status received 06-02-13
!priority High
!difficulty Easy
!qualifier Omission
!subject Add new An_Interface_Type_Definition to Type_Kinds.

!summary

Interface Types, their various kinds and access to their kinds needs to
be added to ASIS.

!question

The Amendment (Ada 2005) defines new Interface types, should these be
Asis.Type_Kinds? (Yes)

!recommendation

(See summary.)

!wording

In clause 3.9.10, add An_Interface_Type_Definition after A_Tagged_Record_Type_Definition
in Type_Kinds:

  An_Interface_Type_Definition,  -- 3.9.4 (2)

In clause 3.9.11, add A_Formal_Interface_Type_Definition to the end of Formal_Type_Kinds:

  A_Formal_Interface_Type_Definition, -- 12.5.5 (2)

    Correct the section references for A_Formal_Access_Type_Definition to 12.5.4(2);
    A_Formal_Unconstrained_Array_Definition to 12.5.3(2), 3.6(3); and
    A_Formal_Constrained_Array_Definition to 12.5.3(2), 3.6(5).

Add a new clause after 3.9.15:

3.9.xx type Interface_Types

   type Interface_Kinds is (  -- 3.9.4 (2)

      Not_An_Interface,                 -- An unexpected element
      An_Ordinary_Interface,            -- 3.9.4(2) interface ...
      A_Limited_Interface,              -- 3.9.4(2) limited interface ...
      A_Task_Interface,                 -- 3.9.4(2) task interface ...
      A_Protected_Interface,            -- 3.9.4(2) protected interface ...
      A_Synchronized_Interface);        -- 3.9.4(2) synchronized interface ...

Add a new clause after 13.17 (in ASIS.Elements):

13.xx function Interface_Kind

   function Interface_Kind
     (Definition : Asis.Definition)
      return Asis.Interface_Kinds;

   Definition specifies the Definition to query.

   Returns the Interface_Kinds value of the Definition.

   Returns Not_An_Interface for any unexpected element such as a
   Nil_Element, A_Statement, or A_Declaration.

   Expected Definition_Kinds:
      A_Type_Definition
      A_Formal_Type_Definition

   Expected Type_Kinds:
      An_Interface_Type_Definition

   Expected Formal_Type_Kinds:
      A_Formal_Interface_Type_Definition

Add new clause at the end of section 15 (Asis.Declarations):

15.xx function Progenitor_List (Declaration)

     function Progenitor_List
     (Declaration : Asis.Definition)
      return Asis.Name_List;

   Declaration specifies the declaration to query.

   Returns a list of subtype marks making up the interface_list in the
   argument declaration, in their order of appearance.

   Appropriate Declaration_Kinds:
      A_Private_Extension_Declaration
      A_Private_Type_Declaration
      A_Task_Type_Declaration
      A_Protected_Type_Declaration
      A_Single_Task_Declaration
      A_Single_Protected_Declaration

   Returns Expression_Kinds:
      An_Identifier
      A_Selected_Component

Add new clause at the end of section 16 (Asis.Definitions):

16.xx function Progenitor_List (Definition)

    function Progenitor_List
      (Type_Definition : Asis.Definition)
       return Asis.Name_List;

   Type_Definition specifies the definition to query.

   Returns a list of subtype marks making up the interface_list in the
   argument definition, in their order of appearance.

   Appropriate Type_Kinds:
      A_Derived_Record_Extension_Definition
      An_Interface_Type_Definition

   Appropriate Formal_Type_Kinds:
      A_Formal_Derived_Type_Definition
      A_Formal_Interface_Type_Definition

   Returns Expression_Kinds:
      An_Identifier
      A_Selected_Component

!discussion

!appendix

Subject: Summary of the proposals for updating the ASIS Standard for Ada 2005
From: Sergey I. Rybin
Date: Mon, 13 Feb 2006 13:55:06 +0300

Formally the ASIS revision process is supposed to be started only after
finishing all the technical work with the new revision of the Ada Standard,
but I think we can start some preliminary technical work with new ASIS
definition already now (all the changes in Ada definition are stable
enough to start the ASIS revision).

At AdaCore we have developed a draft version of the new ASIS specification
and most of the proposed changes are already implemented in the latest
version of GNAT/ASIS technology. The attached file contains the summary
of the changes in the ASIS Standard we have made to adopt the new Ada
features. The interesting thing I've realized when working on
our draft of the new ASIS specification is that if we would like
to keep the upward compatibility as much as possible and if we
would like to keep changes as small as possible,
the new Ada definition gives us very limited freedom in making changes
in the ASIS spec. It does not mean that we think that our proposals
are the only possible solution for ASIS 2005, but it gives us some
hope that we can do ASIS revision for Ada 2005 fast enough.

There is quite a natural mapping of the proposed changes in the ASIS
specification onto the existing set of Ada Issues used for Ada revision,
and the attached file is structured and ordered by AIs. The only
exception is the new values in the ASIS Element Classification needed
to represent the new Ada 2005 predefined attributes and pragmas (of course,
this could be also mapped onto AIs, but I do not think that it would make
sense, because this is the easiest and completely straightforward part
of the ASIS revision).

My main goal of sending this ASIS 2005 Draft summary is to start
the ASIS 2005 discussion. The document itself would hardly be a convenient
background for this discussion - we will have at least split it on
changes related to different language issues, we will also have to
find a way for documenting the revision discussion, probably we
may need a separate mailing list for it. But let's get started!

Sergey Rybin

.....

----------------------------
-- AI-251 Interface Types --
----------------------------
RM-06 3.9.4

* Extend existing element classification:
  - add An_Interface_Type_Definition to Type_Kinds;

  - add A_Formal_Interface_Type_Definition to Formal_Type_Kinds;

  - add to the package Asis the new Interface_Kinds type to classify interface
    definitions:

   type Interface_Kinds is (  -- 3.9.4

      Not_An_Interface,                 -- An unexpected element
      An_Ordinary_Interface,            -- interface ...
      A_Limited_Interface,              -- limited interface ...
      A_Task_Interface,                 -- task interface ...
      A_Protected_Interface,            -- protected interface ...
      A_Synchronized_Interface);        -- synchronized interface ...

  - add new corresponding classification query to Asis.Elements:

   function Interface_Kind
     (Definition : Asis.Definition)
      return       Asis.Interface_Kinds;
------------------------------------------------------------------------------
--  Definition   - Specifies the Definition to query
--
--  Returns the Interface_Kinds value of the Definition.
--
--  Returns Not_An_Interface for any unexpected element such as a
--  Nil_Element, A_Statement, or A_Declaration.
--
--  Expected Definition_Kinds:
--       A_Type_Definition
--       A_Formal_Type_Definition
--
--  Expected Type_Kinds:
--       An_Interface_Type_Definition
--
--  Expected Formal_Type_Kinds:
--       A_Formal_Interface_Type_Definition

* Add two new structural queries - one to Asis.Declarations and another to
  Asis.Definitions for obtaining interface_list

  - Query to be added to Asis.Declarations:

     function Declaration_Interface_List
     (Declaration : Asis.Definition)
      return        Asis.Expression_List;

------------------------------------------------------------------------------
--  Declaration - Specifies the declaration to query
--
--  Returns a list of subtype mark names making up the interface_list in the
--  argument declaration, in their order of appearance.
--
--  Appropriate Declaration_Kinds:
--       A_Private_Extension_Declaration
--       A_Private_Type_Declaration
--       A_Task_Type_Declaration
--       A_Protected_Type_Declaration
--       A_Single_Task_Declaration
--       A_Single_Protected_Declaration
--
--  Returns Expression_Kinds:
--       An_Identifier
--       A_Selected_Component

 - Query to be added to Asis.Definitions:

    function Definition_Interface_List
      (Type_Definition : Asis.Definition)
       return            Asis.Expression_List;

------------------------------------------------------------------------------
--  Type_Definition - Specifies the definition to query
--
--  Returns a list of subtype mark names making up the interface_list in the
--  argument definition, in their order of appearance.
--
--  Appropriate Type_Kinds:
--       A_Derived_Record_Extension_Definition
--       An_Interface_Type_Definition
--
--  Appropriate Formal_Type_Kinds:
--       A_Formal_Derived_Type_Definition
--       A_Formal_Interface_Type_Definition
--
--  Returns Expression_Kinds:
--       An_Identifier
--       A_Selected_Component

****************************************************************