[Top][All Lists]

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

[Gcl-devel] Re: subtypep issues

From: Christophe Rhodes
Subject: [Gcl-devel] Re: subtypep issues
Date: Wed, 31 Aug 2005 21:37:04 +0100
User-agent: Gnus/5.110004 (No Gnus v0.4) Emacs/21.4 (gnu/linux)

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 ...).


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.


reply via email to

[Prev in Thread] Current Thread [Next in Thread]