Re: Record initialisation question

[Shark8 <onewingedshark@gmail.com>]

On Tuesday, January 12, 2021 at 4:38:24 AM UTC-7, Simon Wright wrote:
> Shark8 writes: 
> 
> >> I'll try it but I've just faced another problem where a component of 
> >> another record is the address of the record itself. 
> > 
> > Type Example; 
> > Function To_Address( Input : Access Example ) return System.Address 
> > with Inline; 
> > 
> > Type Example is limited record 
> > Addr : System.Address := To_Address(Example'Access); 
> > End record; 
> > 
> > Package Cvt is new System.Address_To_Access_Conversions(Example); 
> > Function To_Address( Input : Access Example ) return System.Address is 
> > ( Cvt.To_Address( Input.all'Access ) );
> OP wanted to place the data structures in ROM, the chance of this 
> working looks pretty remote 
Yeah, it does, if ROM's the target... but it might work.
The "right way" would be to have an Address-typed parameter on the record, defaulting with Record_Type'Address (using the same Name_in_Definition'Access trick to get the address of the component being created), but we cannot declare discriminants which are not non-scalar or non-access. The other way to do this might be a bit-vector sized as an address, then using Unchecked conversion as the default value.

> (what is it with this weird casing "convention" you use? makes the code 
> quite hard to read ...)
Really?
How so?