async_sequence: Compose asynchronous functions

In r-lib/async: Asynchronous Computation and 'I/O'

Compose asynchronous functions

Description

This is equivalent to using the ⁠$then()⁠ method of a deferred, but it is easier to use programmatically.

Usage

async_sequence(..., .list = NULL)

Arguments

...	Asynchronous functions to compose.
.list	Mose asynchronous functions to compose.

Value

Asynchronous function, the composition of all input functions. They are performed left to right, the ones in .list are the last ones.

See Also

Other async control flow: async_backoff(), async_reflect(), async_retry(), async_retryable(), async_try_each(), async_until(), async_whilst()

Examples

check_url <- async_sequence(
  http_head, function(x) identical(x$status_code, 200L))
synchronise(check_url("https://eu.httpbin.org/status/404"))
synchronise(check_url("https://eu.httpbin.org/status/200"))

r-lib/async documentation built on Nov. 19, 2024, 12:08 p.m.