R: Box a final value for early termination

done {rlang} | R Documentation

## Box a final value for early termination

### Description

A value boxed with `done()` signals to its caller that it should stop iterating. Use it to shortcircuit a loop.

### Usage

    done(x)

    is_done_box(x, empty = NULL)

### Arguments

`x` | For `done()`, a value to box. For `is_done_box()`, a value to test.
`empty` | Whether the box is empty. If `NULL`, `is_done_box()` returns `TRUE` for all done boxes. If `TRUE`, it returns `TRUE` only for empty boxes. Otherwise it returns `TRUE` only for non-empty boxes.

### Value

A boxed value.

### Examples

    done(3)

    x <- done(3)
    is_done_box(x)

[Package rlang version 0.4.7 Index]