On Wed, 4 May 2011, Ravi Varadhan wrote:
I too would like this (being an Indian!).
I would not.
Here is an example that came up just yesterday with regards to solving a quadrature
problem using the "cubature" package. The adaptIntegrate function does not
allow additional arguments via ...
Uwe suggested a work around, but `Curry' would solve it nicely (and it also
tastes better!):
Curry = function(FUN,...) {
.orig = list(...)
function(...) do.call(FUN,c(.orig, list(...)))
}
This has quite different behavior with respect to evaluation/lazy
evaluation than an analogous anonymous function. In addition, do.call
has some fairly strange aspect so it with respect to how it intereacts
with sys.xyz functions, and does not do what you want in many cases I
care about when quote = FALSE, as is the default. Adding this would
create more problems than is solves.
require(cubature)
f <- function(x, a) cos(2*pi*x*a) # a simple test function
# this works
a <- 0.2
adaptIntegrate(function(x, argA=a) f(x, a=argA), lower=0, upper=2)
Yes -- as do a number of other variations.
# but this doesn't work
rm(a)
adaptIntegrate(function(x, argA=a) f(x, a=argA), lower=0, upper=2, a=0.2)
Of course not -- why would anyone think it would?
# Use of Curry
adaptIntegrate(Curry(f, a=0.2), lower=0, upper=2)
The _concept_ of currying is useful, and maybe more can be done to
provide guidance and education on how to do it, but adding a function
that sometimes works and somesimes does surprising things is not the
way to go.
Best,
luke
Best,
Ravi.
-------------------------------------------------------
Ravi Varadhan, Ph.D.
Assistant Professor,
Division of Geriatric Medicine and Gerontology School of Medicine Johns Hopkins
University
Ph. (410) 502-2619
email: rvarad...@jhmi.edu
-----Original Message-----
From: r-devel-boun...@r-project.org [mailto:r-devel-boun...@r-project.org] On
Behalf Of Hadley Wickham
Sent: Wednesday, May 04, 2011 10:29 AM
To: Byron Ellis
Cc: R Development Mailing List
Subject: Re: [Rd] Curry: proposed new functional programming, er, function.
I thought I might bring this up again - it now seems like Curry would
be a natural fit with Reduce, Filter, Find, Map, Negate and Position.
Any chance we might see this in a future version of R?
Hadley
On Thu, Nov 1, 2007 at 2:00 PM, Byron Ellis <byron.el...@gmail.com> wrote:
Hi all (especially R-core) I suppose,
With the introduction of the new functional programming functions into
base I thought I'd ask for a Curry() function. I use a simple one that
looks this:
Curry = function(FUN,...) { .orig = list(...);function(...)
do.call(FUN,c(.orig,list(...))) }
This comes in really handy when using say, heatmap():
heatmap(mydata,hclustfun=Curry(hclust,method="average"))
or other functions where there are ... arguments, but it's not clear
where they should end up.
--
Byron Ellis (byron.el...@gmail.com)
"Oook" -- The Librarian
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--
Luke Tierney
Statistics and Actuarial Science
Ralph E. Wareham Professor of Mathematical Sciences
University of Iowa Phone: 319-335-3386
Department of Statistics and Fax: 319-335-3017
Actuarial Science
241 Schaeffer Hall email: l...@stat.uiowa.edu
Iowa City, IA 52242 WWW: http://www.stat.uiowa.edu
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