all messages for Emacs-related lists mirrored at yhetil.org
 help / color / mirror / code / Atom feed
From: Barry Margolin <barmar@alum.mit.edu>
To: help-gnu-emacs@gnu.org
Subject: Re: empty-line-p
Date: Fri, 30 Mar 2007 01:46:53 -0400	[thread overview]
Message-ID: <barmar-D73634.01465330032007@comcast.dca.giganews.com> (raw)
In-Reply-To: jwv648j70t5.fsf-monnier+gnu.emacs.help@gnu.org

In article <jwv648j70t5.fsf-monnier+gnu.emacs.help@gnu.org>,
 Stefan Monnier <monnier@iro.umontreal.ca> wrote:

> >  (if (looking-at "^[ \t\f\r]*$")
> >      t
> >    nil)))
> 
>   (if <foo> t nil)
> 
> is an eta-regexp, which can be advantageously reduced to just <foo>.
> 
> 
>         Stefan
> 
> 
> PS: The classical eta-regexp is (lambda (x) (<foo> x)), which is equivalent to
> just <foo>.  Another variant is (cons (car <foo>) (cdr <foo>)), which
> eta-reduces to just <foo>.

That last one is different, because the new cons is not eq to the 
original <foo>.

-- 
Barry Margolin, barmar@alum.mit.edu
Arlington, MA
*** PLEASE post questions in newsgroups, not directly to me ***
*** PLEASE don't copy me on replies, I'll read them in the group ***

  reply	other threads:[~2007-03-30  5:46 UTC|newest]

Thread overview: 11+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
     [not found] <mailman.1577.1175177310.7795.help-gnu-emacs@gnu.org>
2007-03-29 14:32 ` empty-line-p Joost Kremers
2007-03-30  8:56   ` empty-line-p David Hansen
2007-03-31  5:49     ` empty-line-p Andreas Roehler
2007-03-31 15:17       ` empty-line-p Xavier Maillard
2007-04-06 14:44         ` empty-line-p Andreas Roehler
     [not found]   ` <mailman.1621.1175289074.7795.help-gnu-emacs@gnu.org>
2007-04-01 20:57     ` empty-line-p Stefan Monnier
2007-03-30  5:36 ` empty-line-p Stefan Monnier
2007-03-30  5:46   ` Barry Margolin [this message]
2007-04-01 20:54     ` empty-line-p Stefan Monnier
2007-03-30  6:14   ` empty-line-p Andreas Roehler
2007-03-29 13:06 empty-line-p Andreas Roehler

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=barmar-D73634.01465330032007@comcast.dca.giganews.com \
    --to=barmar@alum.mit.edu \
    --cc=help-gnu-emacs@gnu.org \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line before the message body.
Code repositories for project(s) associated with this external index

	https://git.savannah.gnu.org/cgit/emacs.git
	https://git.savannah.gnu.org/cgit/emacs/org-mode.git

This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.