Re: Two 'Output questions

[Matthew Heaney <mheaney@on2.com>]

Alex R. Mosteo wrote:
> Hello everybody,
> 
> a) Is there any guarantee that 'Output is implemented like...?
> 
>    1. Write bounds/Tag
>    2. Call to 'Write
> 
> I see that the containers provided with gnat gap 2005 have 'write 
> redefined but not 'output.

Yes, because there's no dope for the container types (as there would be 
for an unconstrained array, for example), and hence only 'Write need to 
defined.

(But do note that I do use ET'Output in the implementation of the 'Write 
for the indefinite containers, since there you really do need to write 
out dope.)


> While I don't see reasons to use 'output on 
> definite types (?), I'm guessing gnat does so because of a). I don't see 
> any explanation in the RM, so if I'm right it may be still 
> gnat-dependent. I suppose it's handy too to not have to redefine both 
> 'Output and 'Write when the latter is enough.

There's nothing gnat-specific about what I did for the containers.  I'm 
assuming that the default 'Output is implemented in terms of the 'Write 
defined for the type (but I would have to look this up to be sure).