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% Generated by roxygen2: do not edit by hand
% Please edit documentation in R/later.R
\name{create_loop}
\alias{create_loop}
\alias{destroy_loop}
\alias{exists_loop}
\alias{current_loop}
\alias{with_temp_loop}
\alias{with_loop}
\alias{global_loop}
\title{Private event loops}
\usage{
create_loop(parent = current_loop(), autorun = NULL)
destroy_loop(loop)
exists_loop(loop)
current_loop()
with_temp_loop(expr)
with_loop(loop, expr)
global_loop()
}
\arguments{
\item{parent}{The parent event loop for the one being created. Whenever the
parent loop runs, this loop will also automatically run, without having to
manually call \code{\link{run_now}()} on this loop. If \code{NULL}, then
this loop will not have a parent event loop that automatically runs it; the
only way to run this loop will be by calling \code{\link{run_now}()} on this
loop.}
\item{autorun}{This exists only for backward compatibility. If set to
\code{FALSE}, it is equivalent to using \code{parent=NULL}.}
\item{loop}{A handle to an event loop.}
\item{expr}{An expression to evaluate.}
}
\description{
Normally, later uses a global event loop for scheduling and running
functions. However, in some cases, it is useful to create a \emph{private}
event loop to schedule and execute tasks without disturbing the global event
loop. For example, you might have asynchronous code that queries a remote
data source, but want to wait for a full back-and-forth communication to
complete before continuing in your code -- from the caller's perspective, it
should behave like synchronous code, and not do anything with the global
event loop (which could run code unrelated to your operation). To do this,
you would run your asynchronous code using a private event loop.
}
\details{
\code{create_loop} creates and returns a handle to a private event loop,
which is useful when for scheduling tasks when you do not want to interfere
with the global event loop.
\code{destroy_loop} destroys a private event loop.
\code{exists_loop} reports whether an event loop exists -- that is, that it
has not been destroyed.
\code{current_loop} returns the currently-active event loop. Any calls to
\code{\link{later}()} or \code{\link{run_now}()} will use the current loop by
default.
\code{with_loop} evaluates an expression with a given event loop as the
currently-active loop.
\code{with_temp_loop} creates an event loop, makes it the current loop, then
evaluates the given expression. Afterwards, the new event loop is destroyed.
\code{global_loop} returns a handle to the global event loop.
}
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