From: "Drew Adams" <drew.adams@oracle.com>
To: <help-gnu-emacs@gnu.org>
Subject: RE: What is the :eval form ?
Date: Sat, 9 Jun 2012 07:08:07 -0700 [thread overview]
Message-ID: <288D2D5C510A45E1ACA1B8F5F6E42F16@us.oracle.com> (raw)
In-Reply-To: <tq4nqlasyb.fsf@news.eternal-september.org>
> > A symbol whose name starts with a colon (`:') is
> > called a "keyword symbol". These symbols automatically
> > act as constants,
when evaluated.
Debugger entered--Lisp error: (setting-constant :foo)
(setq :foo 42)
> Is that also true in a function call?
Is what true? A keyword symbol is just a symbol (a) whose name starts with `:'
and (b) that evaluates to itself.
> e.g (notifications-notify :title "Wazzup!?" :message message))
> title and message are not keywords here.
They are keyword symbols. When they are evaluated (during function
application), the values returned are those same symbols.
> Or is the keyword "symbol" here?
Yes, the key word here is "symbol". Whether or not a keyword symbol serves as a
keyword in some context depends on the context. It means what you want it to
mean. Like everything in Lisp, you can use a keyword symbol as anything you
like.
But it always has properties (a) and (b).
next prev parent reply other threads:[~2012-06-09 14:08 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-06-08 18:39 What is the :eval form ? Philippe M. Coatmeur
2012-06-08 17:56 ` Eli Zaretskii
2012-06-08 18:01 ` Drew Adams
2012-06-08 18:02 ` Tassilo Horn
2012-06-09 6:40 ` Richard Riley
2012-06-09 8:34 ` Thien-Thi Nguyen
2012-06-09 14:08 ` Drew Adams [this message]
2012-06-08 18:08 ` Tassilo Horn
2012-06-08 18:10 ` Drew Adams
2012-06-08 18:21 ` Barry Margolin
[not found] ` <mailman.2446.1339178928.855.help-gnu-emacs@gnu.org>
2012-06-08 19:19 ` Philippe M. Coatmeur
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