Re: Constraint or what?

["Ian Ward" <iward@drawnai.demon.co.uk>]

Dat denk je maar, nieuw Ariel Gaat diep in de vezels...

I have seen this before, I seem to recall that the compiler thought
that, as it was only a subtype of POSITIVE, it did not think that
it was constrained. I demonstrated this on the compiler in question,
by creating a huge range, within a Type

eg. Type x is range 0 .. 2**30-1, or whatever

Then derived the subtype constraint fron the new type,
instead of positive.

    subtype arrayrng is x range 0..30;

 It then worked. I did not investigate
this any further, once I'd got it to work.


Groetjes,
Ian.



Jan Wuyts wrote in message <38A2A395.FD028B73@alcatel.be>...
>Hi guys,
>
>We're doing a port Alsys -> VADS or whatever they are called these
>days.  This maybe a stupid question but I'll take the risk.
>
>The Alsys didn't complain on the construct below but the VADS one does.
>I know about the restrictions on UNCHECKED_CONVERSION and the VADS
>documentation says the target type cannot be an unconstraint array but I
>assumed it was constraint.  So, why does the VADS compiler issue an
>error...
>
>Can anyone help me?
>
>Here is what I do:
>
>--------------------
>...in ADT_ADU...
>   MAX_BINARY_BUFFER_SIZE : constant integer
>      := ADT_ADU_DESCRIPTION.MAX_BINARY_BUFFER_SIZE;
>   subtype T_BINARY_BUFFER_SIZE is
> INTEGER range 0..MAX_BINARY_BUFFER_SIZE;
>   type T_BINARY_BUFFER is array (T_BINARY_BUFFER_SIZE range <>) of
>             NUMERIC_TYPES.UNSIGNED_INTEGER8;
>
>... in NUMERIC_TYPES ...
>  type UNSIGNED_INTEGER8 is range 0 .. 255;
>  for UNSIGNED_INTEGER8'size use 8;
>
>  type UNSIGNED_INTEGER8_ARRAY is
> array (POSITIVE range <>) of UNSIGNED_INTEGER8;
>  pragma PACK (UNSIGNED_INTEGER8_ARRAY);
>
>  subtype BYTE_ARRAY is  UNSIGNED_INTEGER8_ARRAY;
>
>... in the failing procedure...
>DUMP_BIN_BUF:
>declare
>    BUFSIZ : constant ADT_ADU.T_BINARY_BUFFER_SIZE
>              := ADT_ADU.BINARY_BUFFER_SIZE(ADU);
>    BUF : ADT_ADU.T_BINARY_BUFFER(1..BUFSIZ);
>    subtype LIMITED_BYTE_ARRAY_RANGE is
> POSITIVE range 1..BUFSIZ +1;
>
>    subtype LIMITED_BYTE_ARRAY is NUMERIC_TYPES.BYTE_ARRAY
> (LIMITED_BYTE_ARRAY_RANGE);
>    function TO_BYTE_ARRAY is new
> UNCHECKED_CONVERSION (TARGET=> LIMITED_BYTE_ARRAY,
> SOURCE=> ADT_ADU.T_BINARY_BUFFER);
> ---- This is where the VADS compiler says...
> ---- error: RM Appendix F: target type must not be
> ----            unconstrained array or record type
>
>begin
>    ADT_ADU.GET_BINARY_BUFFER(ADU, BUF);
>    return "BUFFER_SIZE=>"& INTEGER'IMAGE(BUFSIZ) & ","
>            & ASCII.LF & "BUFFER=>("
>            & ASCII.LF &
.DUMP_BYTE_ARRAY( 
>                                 TO_BYTE_ARRAY( BUF )
>                                             )
>            & ASCII.LF & ASCII.HT & ")";
>exception
>--------------------
>
>In my opinion LIMITED_BYTE_ARRAY is constraint so...
>
>Thanks for the help
>-- 
>                                        _____________
>      Jan Wuyts (RX)                    \     ^     /
>                                         \ALC/_\TEL/
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