[Gcl-devel] Re: subtypep issues

[Christophe Rhodes]

Camm Maguire <address@hidden> writes:

> Greetimgs!  Just another followup here:
>
> "Paul F. Dietz" <address@hidden> writes:
>
>> > Whoops, I made a mistake reading the page for simple-array.  Yes,
>> > you're right, you can do that.
>> 
>> I want to add that you may not *want* to do it, if it forces
>> array operations to be slow even if the program has a simple-array
>> declaration.
>> 
>
> I think the spec indicates that simple-vector should be (simple-array
> * ...), not (simple-array t ...).

No.

SIMPLE-VECTOR is "The type of a vector that is not displaced to
another array, has no fill pointer, is not expressly adjustable and is
able to hold elements of any type is a subtype of type simple-vector."

The type (SIMPLE-ARRAY * (*)) is the type of all vectors, irrespective
of whether those vectors can hold objects of any type or not.

So SIMPLE-VECTOR is (SIMPLE-ARRAY T (*)) -- vectors which can hold any
object -- not (SIMPLE-ARRAY * (*)) -- vectors of any type.

Christophe