From mboxrd@z Thu Jan  1 00:00:00 1970
From: John Wiegley <jwiegley@gmail.com>
Subject: Re: Newbie elisp programmer requests a pointer to backtics...
Date: Wed, 14 Apr 2010 09:35:43 -0400
Message-ID: <88BCFD2F-7248-4363-8BCE-327282920C21@gmail.com>
References: <4BC50A22.608@pinyon.org>
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To: "Russell L. Carter" <rcarter@pinyon.org>
Cc: emacs-orgmode@gnu.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) =3D> '(foo 123)

They can be nested:

  `(foo `(foo ,,foo))

And lists can be directly interpolated:

  (defvar foo '(123 456))

  `(foo ,foo)  =3D> '(foo (123 456))
  `(foo ,@foo) =3D> '(foo 123 456)

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

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

John=