collect_mirai: mirai (Collect Value)

In mirai: Minimalist Async Evaluation Framework for R

mirai (Collect Value)

Description

Waits for the 'mirai' to resolve if still in progress (blocking but interruptible) and returns its value directly. Equivalent to call_mirai(x)$data.

Usage

collect_mirai(x, options = NULL)

Arguments

x	(mirai | list) a 'mirai' object or list of 'mirai' objects.
options	(character) collection options for list input, e.g. ".flat" or c(".progress", ".stop"). See Options section.

Details

x[] is an equivalent way to wait for and return the value of a mirai x.

Value

An object (the return value of the 'mirai'), or a list of such objects (the same length as x, preserving names).

Options

A named list may also be supplied instead of a character vector, where the names are the collection options. The value for .progress is passed to the cli progress bar: a character value sets the bar name, and a list is passed as named parameters to cli::cli_progress_bar. Examples: c(.stop = TRUE, .progress = "bar name") or list(.stop = TRUE, .progress = list(name = "bar", type = "tasks"))

Alternatively

The value of a 'mirai' may be accessed at any time at ⁠$data⁠, and if yet to resolve, an 'unresolved' logical NA will be returned instead.

Using unresolved() on a 'mirai' returns TRUE only if it has yet to resolve and FALSE otherwise. This is suitable for use in control flow statements such as while or if.

Errors

If an error occurs in evaluation, the error message is returned as a character string of class 'miraiError' and 'errorValue'. is_mirai_error() may be used to test for this. The elements of the original condition are accessible via $ on the error object. A stack trace comprising a list of calls is also available at ⁠$stack.trace⁠, and the original condition classes at ⁠$condition.class⁠.

If a daemon crashes or terminates unexpectedly during evaluation, an 'errorValue' 19 (Connection reset) is returned.

is_error_value() tests for all error conditions including 'mirai' errors, interrupts, and timeouts.

Examples

# using collect_mirai()
df1 <- data.frame(a = 1, b = 2)
df2 <- data.frame(a = 3, b = 1)
m <- mirai(as.matrix(rbind(df1, df2)), df1 = df1, df2 = df2, .timeout = 1000)
collect_mirai(m)

# using x[]
m[]

# mirai_map with collection options
daemons(1, dispatcher = FALSE)
m <- mirai_map(1:3, rnorm)
collect_mirai(m, c(".flat", ".progress"))
daemons(0)

mirai documentation built on Feb. 13, 2026, 9:07 a.m.