Message-ID: <BD232CC7-2612-4E85-8323-0C8A516B9B24@gmail.com>
Date: 2011-06-07T09:57:28Z
From: Peter Dalgaard
Subject: Question about curve function
In-Reply-To: <alpine.LFD.2.02.1106061019430.24233@gannet.stats.ox.ac.uk>
On Jun 6, 2011, at 11:22 , Prof Brian Ripley wrote:
> As a further example of the trickiness, the "function" method of plot() relies on curve(x, ...) being a request to plot the function x(x) against x. I've added a comment to that effect to the help page.
Ouch. This springs to mind:
> fortune(106)
If the answer is parse() you should usually rethink the question.
-- Thomas Lumley
R-help (February 2005)
but curve() predates that insight by half a decade or more. It could probably do with a redesign, if anyone is up to it.
By the way, it really does work if the 2nd arg is an expression object (as opposed to an expression evaluating to an expression object):
do.call(curve,list(expression(x)))
or
cl <- quote(curve(x))
cl[[2]] <- expression(x)
eval(cl)
(The trouble with nonstandard evaluation is that it doesn't follow standard evaluation rules...)
--
Peter Dalgaard
Center for Statistics, Copenhagen Business School
Solbjerg Plads 3, 2000 Frederiksberg, Denmark
Phone: (+45)38153501
Email: pd.mes at cbs.dk Priv: PDalgd at gmail.com