Re: Retrieving Rep Spec'ed Enumeration Values

[scf16!bashford@ford-wdl1.arpa (Dave Bashford)]

In article ... wise@cs.umass.edu writes:
>In article ... mab@dst17.wdl.loral.com (Mark A Biggar) writes:
>   In article I write:
>   >Suppose you had a type like so:
>   >  type Color is ( Red, Green, Blue );
>   >  for Color use ( Red   => 4, Green => 8, Blue  => 16 );
>   >I cannot seem to find a portable way to retrieve the values assigned
>   >in the rep-spec.  Color'Pos is explicitly defined to be unaffected by
>   >the rep spec (LRM 13.3 paragraph 6).
>
>   [suggestion for using unchecked_conversion, ...]
>
>I need to be able to communicate enumeration types over a network
>link.  Transmitting them a string rep ('image) is expensive at both
>ends of the link -- so the rational thing to do seemed to be set the
>numeric representation (they are called ENUMERATION types, you know
>:-) and send that!
>
>   But, if you really really need it just declare an anonymous array to be
>   used for conversions:
>
>   internal_colors: array (Color) of integer := (4,8,16);
>
Am I missing something here ?  Given the following procedures and the
above declarations, and ignoring the storage size problem, both
procedure calls will send exactly the same thing (4), won't they ?

	procedure Send( Value: in Color );
	procedure Send( Value: in integer );
	...
	Send(Red);
	Send(internal_colors(Red));

The reason that there isn't an explicit attribute for retrieving the
value of an enumeration-type object is the same reason that there isn't
one for retrieving the value of an integer-type object - it isn't
necessary.
-- 

db
bashford@srs.loral.com (Dave Bashford, Sunnyvale, CA)