unofficial mirror of help-gnu-emacs@gnu.org
 help / color / mirror / Atom feed
From: Stefan Monnier <monnier@iro.umontreal.ca>
To: help-gnu-emacs@gnu.org
Subject: Re: Macro Expansion Inconsistency
Date: Tue, 16 Dec 2014 18:30:57 -0500	[thread overview]
Message-ID: <jwvwq5rrxb6.fsf-monnier+gmane.emacs.help@gnu.org> (raw)
In-Reply-To: slrnm917tq.h18.joost.m.kremers@j.kremers4.news.arnhem.chello.nl

> (defmacro test (name)
>   `(let* ((name             ',name)
>           (symbol           (intern (concat "some" "-" (symbol-name name)))))
>      ,symbol))

You have 2 macros here: the one you define (test) and the one you use
(backquote).  The problem is in the one you *use*.
I.e. you can reproduce your problem by running the following:

   `(let* ((name             ',"hello")
           (symbol           (intern (concat "some" "-" (symbol-name "hello")))))
      ,symbol))

I.e. the `symbol' variable should be bound in `let' that is executed
during the macro expansion whereas you instead return a form that binds
it (so this `let' binding of `symbol' would only happen later when the
expanded code is executed, which here doesn't happen since you first
try to get the value of `symbol' which signal an error since there is
no such variable at that time).


        Stefan




  parent reply	other threads:[~2014-12-16 23:30 UTC|newest]

Thread overview: 23+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
     [not found] <mailman.16228.1418763453.1147.help-gnu-emacs@gnu.org>
2014-12-16 21:10 ` Macro Expansion Inconsistency Joost Kremers
2014-12-16 21:25   ` Alexander Shukaev
2014-12-16 21:46     ` John Mastro
2014-12-16 22:58       ` Alexander Shukaev
2014-12-16 23:14         ` Alexander Shukaev
2014-12-17  2:19           ` Alexander Shukaev
2014-12-17 10:04             ` Nicolas Richard
2014-12-17 14:03               ` Alexander Shukaev
2014-12-17 14:20                 ` Stefan Monnier
2014-12-17 14:34                   ` Alexander Shukaev
2014-12-17 14:21                 ` Nicolas Richard
2014-12-17 14:52                   ` Alexander Shukaev
2014-12-17 14:58                     ` Nicolas Richard
2014-12-17 15:14                       ` Alexander Shukaev
     [not found]               ` <mailman.16290.1418825041.1147.help-gnu-emacs@gnu.org>
2014-12-17 15:53                 ` Barry Margolin
2014-12-17 16:01                   ` Alexander Shukaev
     [not found]           ` <mailman.16262.1418782759.1147.help-gnu-emacs@gnu.org>
2014-12-17  3:03             ` Rusi
2014-12-17  9:21               ` Nicolas Richard
2014-12-16 23:20         ` John Mastro
     [not found]           ` <CAKu-7WzgoHH=zM_jxeVGMwzAne88nAoCUsLKQv9zUYo_amsjNg@mail.gmail.com>
2014-12-17  3:34             ` John Mastro
2014-12-17  3:41               ` John Mastro
2014-12-16 23:30   ` Stefan Monnier [this message]
2014-12-16 20:57 Alexander Shukaev

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

  List information: https://www.gnu.org/software/emacs/

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

  git send-email \
    --in-reply-to=jwvwq5rrxb6.fsf-monnier+gmane.emacs.help@gnu.org \
    --to=monnier@iro.umontreal.ca \
    --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.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for read-only IMAP folder(s) and NNTP newsgroup(s).