From: Stefan Monnier <monnier@iro.umontreal.ca>
To: help-gnu-emacs@gnu.org
Subject: Re: Concern around use of eval
Date: Thu, 19 Mar 2015 10:07:55 -0400 [thread overview]
Message-ID: <jwv619x6q30.fsf-monnier+gmane.emacs.help@gnu.org> (raw)
In-Reply-To: medrpv$a2h$1@ger.gmane.org
> | (defvar lh/labels '("label1" "label2" "label3"))
> |
> | (defmacro lh/gen-predicate (label)
> | `(defun ,(intern (concat "lh/" label "-p")) ()
> | (member ,label *lh/system-label-store*)))
> |
> | (defun lh/define-predicates ()
> | (dolist (label lh/labels)
> | (eval `(lh/gen-predicate ,label))))
> | (lh/define-predicates)
; -*- lexical-binding:t -*-
(defvar lh/labels '("label1" "label2" "label3"))
(defun lh/gen-predicate (label)
(defalias (intern (concat "lh/" label "-p"))
(lambda () (member label *lh/system-label-store*))))
(defun lh/define-predicates ()
(mapc #'lh/gen-predicate lh/labels))
(lh/define-predicates)
> Stylistically, is there a better way to do this or am I just being
> weird about (eval) and should just get over it?
You're not weird about `eval'. It's kind of like self-modifying code:
there are cases where you *really* need it, but they're extremely rare
and every time you use it when it's not *really* indispensable,
kittens die.
Stefan
next prev parent reply other threads:[~2015-03-19 14:07 UTC|newest]
Thread overview: 17+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-03-19 6:53 Concern around use of eval Les Harris
2015-03-19 8:00 ` Tassilo Horn
[not found] ` <mailman.2302.1426752018.31049.help-gnu-emacs@gnu.org>
2015-03-19 8:12 ` Joost Kremers
2015-03-19 8:31 ` Tassilo Horn
[not found] ` <mailman.2305.1426753885.31049.help-gnu-emacs@gnu.org>
2015-03-20 19:54 ` Joost Kremers
2015-03-19 14:07 ` Stefan Monnier [this message]
2015-03-20 15:17 ` Thierry Volpiatto
2015-03-20 17:19 ` Bug in Elisp font-locking (was: Concern around use of eval) Tassilo Horn
2015-03-20 17:31 ` Bug in Elisp font-locking Stefan Monnier
2015-03-20 17:43 ` Drew Adams
2015-03-20 18:47 ` Tassilo Horn
2015-03-20 20:38 ` Stefan Monnier
2015-03-20 22:45 ` Tassilo Horn
2015-03-21 0:06 ` Johan Bockgård
2015-03-21 7:26 ` Tassilo Horn
2015-03-21 2:33 ` Stefan Monnier
2015-03-21 7:55 ` Tassilo Horn
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