Re: Your wish list for Ada 202X

["björn lundin" <b.f.lundin@gmail.com>]

Den onsdagen den 23:e april 2014 kl. 16:06:55 UTC+2 skrev Dmitry A. Kazakov:
> On Wed, 23 Apr 2014 05:55:00 -0700 (PDT), björn lundin wrote:

> > I'd like V'Img to be standard ada like T'Image(V);
> > As in the gnat implementation
> V means value, not an object? A value could be ambiguous. E.g.

Yes value. Sorry if I was not clear.

> 
> OK, considering no place for the sign as in T'Image(V), the image of a
> modular and of an integer type will be same. But what about floating point
> types:

I stated discrete_types.

> > type T is some_discrete_type
> 

 
> > Also, I'd like to be able to define the string function
> > for a record type to be used for the 'image attribute.
> The only reason why anybody would use an attribute over a [primitive]
> function is that the attribute 'Image is predefined by the
> language/compiler. If record types ought to get 'Img, you should specify
> how to generate it for whatever record type.

No. Not the only reason.
Another reason is when you work on a legacy system, 
that was implemented with Ada83.
The system then turns out to be stubbornly vital, 
so it won't go away for many years. But there are
few or no tagged types. 

So, being able to define an 'Img attribute on eg

  type AD_ASSIGNMENT_RECORD is
    record
      ASSIGNMENT_ID          : ASSIGNMENT_ID_TYPE;
      ASSIGNMENT_MODE        : ASSIGNMENT_MODE_TYPE;
      ASSIGNMENT_TYPE        : ASSIGNMENT_TYPE_TYPE;
      CURRENT_ADDRESS        : ADDRESS_TYPE;
      DESTINATION            : ADDRESS_TYPE;
      PRIORITY               : INTEGER_4;
      LAST_ASSIGNMENT        : YESNO_TYPE;
      LOAD_TYPE              : PALLET_CODE_TYPE;
      LOAD_HEIGHT            : HEIGHT_CODE_TYPE;
      LOAD_WEIGHT            : INTEGER_4;
      ZONE                   : INTEGER_4;
      HANDLER                : ADDRESS_TYPE;
      SEMI_AUTO_SUB_SYSTEM_ID: SUB_SYSTEM_ID_TYPE;
      SEQUENCE_ID            : STRING(1..SEQUENCE_ID_MAX_LENGTH);
      PALLET_ID              : PALLET_ID_TYPE;
      ADDITIONAL_INFO_LENGTH : ADDITIONAL_INFORMATION_LENGTH_TYPE;
      ADDITIONAL_INFO        : ADDITIONAL_INFORMATION_TYPE;
      FILLER_1               : STRING(1..2);		                -- v8.1
      TRANSPORT_TYPE         : INTEGER_4;		                    -- v9.1
      SHIPPING_DATE          : SATTMATE_CALENDAR.TIME_TYPE;		  -- v9.1
      FILLER_2               : STRING(1..2);		                -- v9.1
    end record;

  for AD_ASSIGNMENT_RECORD'alignment use 4;
  for AD_ASSIGNMENT_RECORD use       -- V6.5b
    record
      ASSIGNMENT_ID           at   0 range 0..31;       -- V6.5b
      ASSIGNMENT_MODE         at   4 range 0..31;       -- V6.5b
      ASSIGNMENT_TYPE         at   8 range 0..31;       -- V6.5b
      CURRENT_ADDRESS         at  12 range 0..8*24-1;   -- V6.5b
      DESTINATION             at  36 range 0..8*24-1;   -- V6.5b
      PRIORITY                at  60 range 0..31;       -- V6.5b
      LAST_ASSIGNMENT         at  64 range 0..31;       -- V6.5b
      LOAD_TYPE               at  68 range 0..31;       -- V6.5b
      LOAD_HEIGHT             at  72 range 0..31;       -- V6.5b
      LOAD_WEIGHT             at  76 range 0..31;       -- V6.5b
      ZONE                    at  80 range 0..31;       -- V6.5b
      HANDLER                 at  84 range 0..8*24-1;   -- V6.5b
      SEMI_AUTO_SUB_SYSTEM_ID at 108 range 0..31;       -- V6.5b
      SEQUENCE_ID             at 112 range 0..8*4-1;    -- V6.5b
      PALLET_ID               at 116 range 0..8*16-1;		-- V6.5b, v8.1
      ADDITIONAL_INFO_LENGTH  at 132 range 0..31;       -- V6.5b, v8.1
      ADDITIONAL_INFO         at 136 range 0..8*50-1;   -- V6.5b, v8.1
      FILLER_1                at 186 range 0..8*2-1;    -- v8.1
      TRANSPORT_TYPE          at 188 range 0..31;       -- v9.1
      SHIPPING_DATE           at 192 range 0..16*7-1;   -- v9.1
      FILLER_2                at 206 range 0..8*2-1;    -- v9.1
    end record;								-- V6.5b

  for AD_ASSIGNMENT_RECORD'SIZE use 8*208;			-- V6.5b, v8.1, v9.1


would be really nice.
All types within the record are 2 or 4 bytes integers or strings

(The representation clauses where vital for sending record like this
 with generic functions using ipc on vax/ppc/ and intel boxes.
 They also where importatant when sending BETWEEN ppc and intelboxes.
 This is now rewritten, but not tested without the representation clauses 
 so I do not dear to remove them just yet 
)


/Björn