From mboxrd@z Thu Jan 1 00:00:00 1970 Path: news.gmane.org!not-for-mail From: John Mastro Newsgroups: gmane.emacs.help Subject: Re: Canonical way of marking a buf local var to be safe if nil/t? Date: Thu, 12 May 2016 10:39:04 -0700 Message-ID: References: NNTP-Posting-Host: plane.gmane.org Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: quoted-printable X-Trace: ger.gmane.org 1463074780 9228 80.91.229.3 (12 May 2016 17:39:40 GMT) X-Complaints-To: usenet@ger.gmane.org NNTP-Posting-Date: Thu, 12 May 2016 17:39:40 +0000 (UTC) Cc: Kaushal Modi To: Help Gnu Emacs mailing list Original-X-From: help-gnu-emacs-bounces+geh-help-gnu-emacs=m.gmane.org@gnu.org Thu May 12 19:39:39 2016 Return-path: Envelope-to: geh-help-gnu-emacs@m.gmane.org Original-Received: from lists.gnu.org ([208.118.235.17]) by plane.gmane.org with esmtp (Exim 4.69) (envelope-from ) id 1b0uaJ-0005Da-CS for geh-help-gnu-emacs@m.gmane.org; Thu, 12 May 2016 19:39:39 +0200 Original-Received: from localhost ([::1]:59025 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1b0uaI-0000P9-Q5 for geh-help-gnu-emacs@m.gmane.org; Thu, 12 May 2016 13:39:38 -0400 Original-Received: from eggs.gnu.org ([2001:4830:134:3::10]:45620) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1b0ua5-0000KD-QT for help-gnu-emacs@gnu.org; Thu, 12 May 2016 13:39:26 -0400 Original-Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1b0ua4-0000oE-S2 for help-gnu-emacs@gnu.org; Thu, 12 May 2016 13:39:25 -0400 Original-Received: from mail-yw0-x22d.google.com ([2607:f8b0:4002:c05::22d]:36242) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1b0ua4-0000nr-P3 for help-gnu-emacs@gnu.org; Thu, 12 May 2016 13:39:24 -0400 Original-Received: by mail-yw0-x22d.google.com with SMTP id o66so90033068ywc.3 for ; Thu, 12 May 2016 10:39:24 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20120113; h=mime-version:in-reply-to:references:from:date:message-id:subject:to :cc:content-transfer-encoding; bh=1O4O4S5tVDuxiJTNtq6Q71rf0uf+mtM1Ayp85rsiHZ8=; b=aMcvjzTh+rDU3BzOYuSR6Homc/ZbiEdZcUDMHAxHASu1d8Ka7SdpxcXv2qEQz4LkBK 9HfeJk0/IS+ayGWW8y9dmEs21dkHxDrMENvXN3BEeqOf5SZBSw9jCXmZYilcdChtRwpo jit8uACArZ4doGs06u0XjdKrBqT4d02SCm7xpT/BHzi98/bySspIOgN/8gWKAc5QKNaX LlKU1AgRvnB/98jwa/EyfJa9z+FAN7aqIsDioIXlVXV2i5GYAixJw5SSO9T8f+cZjlu4 1htL+OhsZlU+G/EDrhTG+JPcyHVKGKqIZI7Uld3eWCPlYU3DB5T5je3AaepRGqSMqcpl 1Jiw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20130820; h=x-gm-message-state:mime-version:in-reply-to:references:from:date :message-id:subject:to:cc:content-transfer-encoding; bh=1O4O4S5tVDuxiJTNtq6Q71rf0uf+mtM1Ayp85rsiHZ8=; b=R4P69c10yOWKgkiLGwr0s17DVAMBuj/uY6P6V8Buj0ItflOrOWWBz02PFFt4hcf/ty OzeMn6LYmXHgWkKXP1/8LtchaqJuAbKvpzSDxxBjOVyiPbJIWKchMA74fMvxUYCt4203 htpZA2bJG+3PELP3/MXGYxoq4PbBHNEJ7lgt3vP4QSk/f9UFkr0e+p1VXw3WPZV4eV7T 72hfvJydgGc/xGSA78FxiujpdCrjP2M0e6ukzCyxcK5q947Sc7vDlw2yUc/V2NKPMHU2 e2AvHE+azCglr3EK1Xsy80Vg1Bv+3mnlLGbQdaz3L2AwGNtFW7orAauTHYu4opjD2O+h FjoQ== X-Gm-Message-State: AOPr4FVO9WzvFMZFJpc3oHdjndPVNZ2o20XZI7A2bPzV6XdPOtoQmeDXd2wC4J7VLrhgttZPHXtrGxMXW0W4Qw== X-Received: by 10.129.51.140 with SMTP id z134mr5023634ywz.322.1463074764217; Thu, 12 May 2016 10:39:24 -0700 (PDT) Original-Received: by 10.37.98.81 with HTTP; Thu, 12 May 2016 10:39:04 -0700 (PDT) In-Reply-To: X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.2.x-3.x [generic] X-Received-From: 2607:f8b0:4002:c05::22d X-BeenThere: help-gnu-emacs@gnu.org X-Mailman-Version: 2.1.21 Precedence: list List-Id: Users list for the GNU Emacs text editor List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: help-gnu-emacs-bounces+geh-help-gnu-emacs=m.gmane.org@gnu.org Original-Sender: "help-gnu-emacs" Xref: news.gmane.org gmane.emacs.help:109936 Archived-At: Kaushal Modi wrote: > What would be a canonical way (if any) of setting a var to be a safe buff= er > local variable as long as its value is either nil or t? > > I use > > (put 'my-foo-var 'safe-local-variable (lambda (val) (or (equal val nil) > (equal val t)))) Use `booleanp': booleanp is a compiled Lisp function in =E2=80=98subr.el=E2=80=99. (booleanp OBJECT) Return t if OBJECT is one of the two canonical boolean values: t or nil. Otherwise, return nil. --=20 john