future (version 1.4.0)

Future-class: A future represents a value that will be available at some point in the future

Description

A future is an abstraction for a value that may available at some point in the future. A future can either be unresolved or resolved, a state which can be checked with resolved(). As long as it is unresolved, the value is not available. As soon as it is resolved, the value is available via value().

Usage

Future(expr = NULL, envir = parent.frame(), substitute = FALSE,
  globals = NULL, packages = NULL, seed = NULL, lazy = FALSE,
  local = TRUE, gc = FALSE, earlySignal = FALSE, label = NULL, ...)

Arguments

expr

An R expression.

envir

The environment in which the evaluation is done (or inherits from if local is TRUE).

substitute

If TRUE, argument expr is substitute():ed, otherwise not.

globals

(optional) a named list of global objects needed in order for the future to be resolved correctly.

packages

(optional) a character vector specifying packages to be attached in the R environment evaluating the future.

seed

(optional) A L'Ecuyer-CMRG RNG seed.

lazy

If FALSE (default), the future is resolved eagerly (starting immediately), otherwise not.

local

If TRUE, the expression is evaluated such that all assignments are done to local temporary environment, otherwise the assignments are done to the global environment of the R process evaluating the future.

gc

If TRUE, the garbage collector run (in the process that evaluated the future) after the value of the future is collected. Some types of futures ignore this argument.

earlySignal

Specified whether conditions should be signaled as soon as possible or not.

label

An optional character string label attached to the future.

…

Additional named elements of the future.

Value

An object of class Future.

Details

A Future object is itself an environment.

See Also

One function that creates a Future is future(). It returns a Future that evaluates an R expression in the future. An alternative approach is to use the %<-% infix assignment operator, which creates a future from the right-hand-side (RHS) R expression and assigns its future value to a variable as a promise.