1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
|
#' @inheritParams ClusterFuture-class
#' @inheritParams Future-class
#'
#' @return
#' \code{MultisessionFuture()} returns an object of class
#' \code{MultisessionFuture}, which inherits from \code{ClusterFuture}.
#'
#' @export
#' @rdname ClusterFuture-class
MultisessionFuture <- function(expr = NULL, envir = parent.frame(), substitute = FALSE, globals = TRUE, persistent = FALSE, local = !persistent, workers = NULL, ...) {
if (substitute) expr <- substitute(expr)
f <- ClusterFuture(expr = expr, envir = envir, substitute = FALSE, globals = globals, persistent = persistent, local = local, workers = workers, ...)
structure(f, class = c("MultisessionFuture", class(f)))
}
#' @export
getExpression.MultisessionFuture <- function(future, mc.cores = 1L, ...) {
## NOTE: In order to override the default 'mc.cores = NULL' of
## getExpression.Future(), we have to pass it as a named argument to
## NextMethod(). If not done, that is, if we just call NextMethod(), then
## 'mc.cores' will resolve to the default (= NULL). If we don't name the
## argument - NextMethod("getExpression", mc.cores) - then the default
## will still be NULL.
## The problem with using NextMethod(mc.cores = mc.cores) is that if we
## call getExpression(f, 2L) instead of getExpression(f, mc.cores = 2L),
## then the call will become getExpression.Future(f, 2L, mc.cores = 2L).
## I don't think there is a solution here, except to enforce that all
## arguments to a method that uses NextMethod() must be named.
## See also https://github.com/HenrikBengtsson/Wishlist-for-R/issues/44
## /HB 2018-06-13
## Assert that no arguments but the first is passed by position
assert_no_positional_args_but_first()
NextMethod(mc.cores = mc.cores)
}
|
