R: Get the future of a future variable

futureOf {future} | R Documentation

## Get the future of a future variable

### Description

Get the future of a future variable that has been created directly or indirectly via `future()`.

### Usage

    futureOf(var = NULL, envir = parent.frame(), mustExist = TRUE,
      default = NA, drop = FALSE)

### Arguments

`var` | the variable. If NULL, all futures in the environment are returned.
`envir` | the environment where to search from.
`mustExist` | If TRUE and the variable does not exists, then an informative error is thrown, otherwise NA is returned.
`default` | the default value if future was not found.
`drop` | if TRUE and `var` is NULL, then returned list only contains futures, otherwise also `default` values.

### Value

A Future (or `default`). If `var` is NULL, then a named list of Future:s are returned.

### Examples

    a %<-% { 1 }

    f <- futureOf(a)
    print(f)

    b %<-% { 2 }

    f <- futureOf(b)
    print(f)

    ## All futures
    fs <- futureOf()
    print(fs)

    ## Futures part of environment
    env <- new.env()
    env$c %<-% { 3 }

    f <- futureOf(env$c)
    print(f)

    f2 <- futureOf(c, envir = env)
    print(f2)

    f3 <- futureOf("c", envir = env)
    print(f3)

    fs <- futureOf(envir = env)
    print(fs)

[Package future version 1.9.0 Index]