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From: John Wiegley <jwiegley@gmail.com>
To: "Russell L. Carter" <rcarter@pinyon.org>
Cc: emacs-orgmode@gnu.org
Subject: Re: Newbie elisp programmer requests a pointer to backtics...
Date: Wed, 14 Apr 2010 09:35:43 -0400	[thread overview]
Message-ID: <88BCFD2F-7248-4363-8BCE-327282920C21@gmail.com> (raw)
In-Reply-To: <4BC50A22.608@pinyon.org>

A back-quoted form is just like a quoted form, except every ,foo is substituted by the evaluation of foo.

  (defvar foo 123)

  `(foo ,foo) => '(foo 123)

They can be nested:

  `(foo `(foo ,,foo))

And lists can be directly interpolated:

  (defvar foo '(123 456))

  `(foo ,foo)  => '(foo (123 456))
  `(foo ,@foo) => '(foo 123 456)

You can do this to see how any form will expand:

  M-: (pp-to-string (macroexpand `(foo ,foo)))

John

      parent reply	other threads:[~2010-04-14 13:35 UTC|newest]

Thread overview: 7+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2010-04-14  0:19 Newbie elisp programmer requests a pointer to backtics Russell L. Carter
2010-04-14  9:52 ` David Maus
2010-04-14 16:13   ` Russell L. Carter
2010-04-14  9:58 ` Thomas Jost
2010-04-14 15:05   ` Dan Davison
2010-04-14 16:31     ` Russell L. Carter
2010-04-14 13:35 ` John Wiegley [this message]

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