future (version 1.10.0)

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,
  stdout = TRUE, globals = NULL, packages = NULL, seed = NULL,
  lazy = FALSE, local = TRUE, gc = FALSE, earlySignal = FALSE,
  label = NULL, ...)

Arguments

expr

An R expression.

envir

The environment from where global objects should be identified.

substitute

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

stdout

If TRUE (default), then the standard output is captured, and re-outputted when value() is called. If FALSE, any output is silenced (by sinking it to the null device as it is outputted). If NA (not recommended), output is not intercepted.

globals

(optional) a logical, a character vector, or a named list to control how globals are handled. For details, see section 'Globals used by future expressions' in the help for future().

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.