From: "Drew Adams" <drew.adams@oracle.com>
To: "troelskn" <troelskn@gmail.com>, <help-gnu-emacs@gnu.org>
Subject: RE: Assign a function to a variable, and invoke it
Date: Mon, 30 Jul 2007 15:56:16 -0700 [thread overview]
Message-ID: <DNEMKBNJBGPAOPIJOOICGEGMDOAA.drew.adams@oracle.com> (raw)
In-Reply-To: <1185834175.653370.242000@22g2000hsm.googlegroups.com>
> (defvar my-browse-url 'browse-url)
> ...
> (my-browse-url "http://example.com")
>
> I suppose that functions and variables have different namespaces in
> elisp? How do I invoke the function, which my-browse-url points to?
Invoke the function using `funcall' or `apply': (funcall my-browse-url).
A symbol, such as `my-browse-url' or `browse-url', has a value cell and a
function cell, so the same symbol can act as a function (via its function
cell) and as a variable (via its value cell).
When evaluated, the symbol's value is returned (from its value cell). In a
function call, as in (browse-url), its function cell is used. When you do
(funcall my-browse-url), the symbol `my-browse-url' is evaluated (value
cell) to the symbol `browse-url', and then the function in the function cell
of that symbol, `browse-url', is called (by `funcall').
See the Elisp manual in Emacs (C-h i) for a better and more complete
explanation of all of this - it is your friend.
prev parent reply other threads:[~2007-07-30 22:56 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2007-07-30 22:22 Assign a function to a variable, and invoke it troelskn
2007-07-30 22:52 ` troelskn
2007-07-30 22:56 ` Joost Kremers
2007-07-30 22:56 ` Drew Adams [this message]
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