[Top][All Lists]

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

Re: [RFC] caar/cadr/cdar/cddr

From: Samuel Bronson
Subject: Re: [RFC] caar/cadr/cdar/cddr
Date: Thu, 12 Jul 2012 17:46:18 -0400

On Jul 12, 2012, at 1:44 PM, Dmitry Antipov wrote:

On 07/12/2012 08:53 PM, Paul Eggert wrote:

How widely?  I've always been leery about those
functions, myself.

$ grep -nHR "(car (car (" lisp | wc -l
$ grep -nHR "(car (cdr (" lisp | wc -l
$ grep -nHR "(cdr (car (" lisp | wc -l
$ grep -nHR "(cdr (cdr (" lisp | wc -l

Since this is a performance
improvement, how much does performance improve?

Not yet because byte-opt.el should be able to optimize
(car (cdr X)) -> (cadr X) etc. Or, all Lisp sources
should be converted manually :-).

Quite possibly they're a win in the C implementation,
but I'm not sure they're worth adding bytecodes for.

Calling them via Funcall is too slow.

What Funcall? The byte compiler uses the appropriate sequence of Bcar/ Bcdr ...

reply via email to

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