Error: object of type 'closure' is not subsettable

I thought it would be possible to make rep() work for functions
by writing a method for the function class. I tried:

rep.function <- function(x,...) {
times <- as.list(...)[[1]]
rslt <- vector("list",times)
rslt[1:times] <- list(x)
rslt
}

But then doing

rep(sin,2)

still gave an error --- Error: object of type 'builtin' is not subsettable

Note the difference: ``builtin'' rather than ``closure''.

I then noticed that there is no generic function for rep, although
there are ***methods*** for rep. I don't understand this at all!

So I did:

rep.default <- rep
rep <- function(x,...){UseMethod("rep")}

Having taken these steps, rep(sin,2) worked as expected.

But why doesn't rep() have a generic form? And how can there
be methods ***without*** a generic? Can anyone explain the
issues to me, preferably in terms that are comprehensible to
the human mind (which is what I'm equipped with)?

cheers,

Rolf Turner

On 14/01/2010, at 2:24 PM, Gabor Grothendieck wrote:

See ?rep where it says that the argument must be a vector. Try
rep(list(sin), 3)

On Wed, Jan 13, 2010 at 8:11 PM, Matthew Walker
<matthew.walker.1 at ulaval.ca> wrote:

Hi everyone,

Would somebody please explain (or point me to a reference that
explains) the
following error:

"Error: object of type 'closure' is not subsettable"

I was trying to use rep() to replicate a function:

example_function <- function() { return(TRUE) }
rep(example_function, 3)

Error: object of type 'closure' is not subsettable

But I just cannot understand this error. I can combine functions
using "c"
without any problems:

c(example_function, example_function)

[[1]]
function ()
{
return(TRUE)
}

[[2]]
function ()
{
return(TRUE)
}

What am I doing wrong when I use rep()?

Thanks in advance,

Matthew Walker