call_mirai: mirai (Call Value)

In mirai: Minimalist Async Evaluation Framework for R

mirai (Call Value)

Description

Waits for the 'mirai' to resolve if still in progress, stores the value at ⁠$data⁠, and returns the 'mirai' object.

Usage

call_mirai(x)

Arguments

x	a 'mirai' object, or list of 'mirai' objects.

Details

Accepts a list of 'mirai' objects, such as those returned by mirai_map(), as well as individual 'mirai'.

Waits for the asynchronous operation(s) to complete if still in progress, blocking but user-interruptible.

x[] may also be used to wait for and return the value of a mirai x, and is the equivalent of call_mirai(x)$data.

Value

The passed object (invisibly). For a 'mirai', the retrieved value is stored at ⁠$data⁠.

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 call_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)
call_mirai(m)$data

# using unresolved()
m <- mirai(
  {
    res <- rnorm(n)
    res / rev(res)
  },
  n = 1e6
)
while (unresolved(m)) {
  cat("unresolved\n")
  Sys.sleep(0.1)
}
str(m$data)

mirai documentation built on Sept. 9, 2025, 5:51 p.m.