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Re: never use `eval' (was: Re: How to mapcar or across a list?)
From: |
Barry Margolin |
Subject: |
Re: never use `eval' (was: Re: How to mapcar or across a list?) |
Date: |
Wed, 15 Jul 2015 20:04:23 -0400 |
User-agent: |
MT-NewsWatcher/3.5.3b3 (Intel Mac OS X) |
In article <mailman.6984.1437004760.904.help-gnu-emacs@gnu.org>,
Emanuel Berg <embe8573@student.uu.se> wrote:
> John Mastro <john.b.mastro@gmail.com> writes:
>
> > I would use something like this:
> >
> > (defmacro ...
>
> Macros never liked me, and that is mutual. Are they
> really preferrable to `eval'?
>
> > For this (and others like it)
>
> ... which are? Do you mean the eval + backquote combo?
>
> > it looks like you could instead simply use e.g.
> > (apply #'create-book nil title data)
>
> This is what it looks like:
>
> (eval `(create-book nil ,title ,@data))
>
> With `apply', won't the last "data" be a list, i.e.
>
> (a b ... n)
>
> instead of
>
> a b ... n
>
> ?
No. apply spreads its last argument. You're thinking of funcall.
--
Barry Margolin, barmar@alum.mit.edu
Arlington, MA
*** PLEASE post questions in newsgroups, not directly to me ***
- Re: How to mapcar or across a list?, (continued)
- Re: How to mapcar or across a list?, Rasmus, 2015/07/15
- Re: How to mapcar or across a list?, John Mastro, 2015/07/15
- Re: How to mapcar or across a list?, Emanuel Berg, 2015/07/15
- Message not available
- Re: How to mapcar or across a list?, Pascal J. Bourguignon, 2015/07/15
- Re: How to mapcar or across a list?, Emanuel Berg, 2015/07/15
- never use `eval' (was: Re: How to mapcar or across a list?), Emanuel Berg, 2015/07/15
- Re: never use `eval' (was: Re: How to mapcar or across a list?), John Mastro, 2015/07/15
- Re: never use `eval' (was: Re: How to mapcar or across a list?), Emanuel Berg, 2015/07/15
- Re: never use `eval' (was: Re: How to mapcar or across a list?), John Mastro, 2015/07/15
- Message not available
- Re: never use `eval' (was: Re: How to mapcar or across a list?),
Barry Margolin <=
- Message not available
- Re: never use `eval' (was: Re: How to mapcar or across a list?), Barry Margolin, 2015/07/15
- Re: never use `eval' (was: Re: How to mapcar or across a list?), Emanuel Berg, 2015/07/15
- Re: never use `eval' (was: Re: How to mapcar or across a list?), Emanuel Berg, 2015/07/16
- Message not available
- Re: never use `eval', Pascal J. Bourguignon, 2015/07/16
- Re: never use `eval', Emanuel Berg, 2015/07/16
- Re: never use `eval', Barry Margolin, 2015/07/17
- Re: never use `eval', Pascal J. Bourguignon, 2015/07/17
- Message not available
- Re: never use `eval', Pascal J. Bourguignon, 2015/07/15
- Re: never use `eval', Emanuel Berg, 2015/07/15
Re: How to mapcar or across a list?, Pascal J. Bourguignon, 2015/07/15