R: A future represents a value that will be available at some...

Future-class {future} | R Documentation

## 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.

### Details

A Future object is itself an environment.

### Value

An object of class `Future`.

### 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.

[Package future version 1.9.0 Index]