Add with(<plan>, <expression>)

Author: HenrikBengtsson

DESCRIPTION

@@ -1,5 +1,5 @@
 Package: future
-Version: 1.34.0-9301
+Version: 1.34.0-9302
 Title: Unified Parallel and Distributed Processing in R for Everyone
 Imports:
     digest,

NAMESPACE

@@ -86,6 +86,7 @@ S3method(value,Future)
 S3method(value,environment)
 S3method(value,list)
 S3method(value,listenv)
+S3method(with,FutureStrategyList)
 export("%->%")
 export("%<-%")
 export("%conditions%")

NEWS.md

@@ -15,6 +15,9 @@
    on having to specify globals and packages, not having conditions
    and standard output relayed, and ignoring random number generation.
 
+ * Add `with(<plan>, <expression>)` method to evaluate an expression,
+   including futures, using a temporary future plan.
+
 ## Bug Fixes
 
  * Now 'interrupt' conditions are captured during the evaluation of

R/utils_api-with.R

@@ -0,0 +1,18 @@
+#' Evaluate an expression using a temporarily set future plan
+#'
+#' @param data The future plan to use temporarily.
+#'
+#' @param The R expression to be evaluated.
+#'
+#' @param \ldots Not used.
+#'
+#' @return The value of the expression evaluated.
+#'
+#' @example incl/with.R
+#'
+#' @export
+with.FutureStrategyList <- function(data, expr, ...) { 
+  on.exit(plan(data))
+  plan("next")
+  expr
+}

incl/with.R

@@ -0,0 +1,7 @@
+# Evaluate a future using the 'multisession' plan
+with(plan(multisession, workers = 2), {
+  f <- future(Sys.getpid())
+  w_pid <- value(f)
+  c(main = Sys.getpid(), worker = w_pid)
+})
+