GNU bug report logs - #16963
A patch to create a list-with-tail primitive.

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From: Demetrios Obenour <demetriobenour <at> gmail.com>
To: Daniel Colascione <dancol <at> dancol.org>
Cc: 16963 <at> debbugs.gnu.org, Stefan <monnier <at> IRO.UMontreal.CA>
Subject: bug#16963: A patch to create a list-with-tail primitive.
Date: Thu, 27 Mar 2014 20:43:47 -0400

On Thu, 2014-03-27 at 16:38 -0700, Daniel Colascione wrote:
> On 03/27/2014 04:37 PM, Demetrios Obenour wrote:
> > On Mon, 2014-03-24 at 19:45 -0700, Daniel Colascione wrote:
> >> On 03/24/2014 07:10 PM, Stefan wrote:
> >>>> Since a comment in backquote.el said that backquote-list* needed to be a
> >>>> primitive, here is an implementation of it as one, under the name
> >>>> list-with-tail.
> >>>
> >>> I think it would make more sense to call it `list*'.  Also it might make
> >>> sense to change backquote.el so it uses this `list*' (tho probably only
> >>> when passed with enough arguments).
> >>
> >> Agreed. On more that one occasion, I've wished we had a CL-less `list*'.
> >> If you do add this feature, please make sure the existing list* compiler
> >> macros keep working.
> >>
> > What about just deleting these compiler macros, and making cl-list* an
> > alias for list*?
> > 
> > There seems to be little point in keeping them if list* is a primitive.
> 
> The new list* doesn't have an opcode, but cons does.
> 

Ah I see -- there might be a speed advantage in repeated cons calls, up
to a point. At what point would the function look-up be slower than
repeated function calls (I thought that function calls in Emacs Lisp are
slow)?

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