Re: [Sbcl-help] Array of structures

[Paul K. <pv...@pv...>]

In article <2AD...@se...>,
 james anderson <jam...@se...> wrote:
> On 2010-04-26, at 21:45 , Paul Khuong wrote:
> 
> > In article <326...@se...>,
> >  james anderson <jam...@se...> wrote:
> >> On 2010-04-25, at 22:56 , Paul Khuong wrote:
> >>> The problem is that this breaks object identity. The semantics of CL
> >>> dictate that, given A an array of TEST, I can do
> >>>  (setf (aref A 0) (aref A 1))
> >>> and both indices should point to the same (wrt object identity)
> >>> object.
> >>> For instance, side-effects to the structure in either index will be
> >>> reflected in the other.
> > [...]
> >> Where is this constraint specified?
> >
> > What constraint? That the implementation won't copy objects behind  
> > your
> > back?
> 
> i'm more concerned with "before your very eyes."
> that is, is it anywhere specified that a conforming implementation  
> could not define the behavior of simple-array to include structures.  
> with the same consequences as for floating point numbers.

EQ is defined to work on structures, unlike numbers.