SkriptLang
Tasks (Prototype 1)
The Basics
A task is like a little function.
set {cool task} to a task:
broadcast "Hello!"
run {cool task}
However, there are two important differences:
- tasks can't be reused
set {task} to a task:
broadcast "Hello!"
run {task}
run {task} # does nothing :(
- the completion of a task can be waited for
set {monitor me} to false
set {task} to a task:
wait 5 seconds
set {monitor me} to true
complete the current task
run {task}
{monitor me} is false
wait for {task}
{monitor me} is true
Importantly, this is a safe and low-overhead wait, which should be much more efficient than a busy-waiting while <...>: wait 1 tick.
The trigger will sleep until the task reports as finished (or cancelled). Other triggers are not affected: Skript can process everything else while that trigger is sleeping.
Waiting
A task can be waited for. The wait will automatically end if:
- The task is marked as complete,
- either by itself
- or by another trigger.
- or by the auto-completion flag
- The task is forcibly cancelled.
- The task is already complete/cancelled.
set {task} to a task:
wait 5 seconds
complete the current task
run {task}
wait for {task} # waits
wait for {task} # doesn't wait, task is already done
set {task} to a task:
wait 5 seconds
complete the current task
run {task}
cancel {task}
wait for {task} # doesn't wait, task is cancelled
If a task does not mark itself 'complete' at the end, it will be waited for indefinitely.
set {task} to a task:
broadcast "hello"
run {task}
wait for {task} # Uh oh... we will wait forever!
This is by design: a task can be completed and/or cancelled from another trigger. You can use this to set up safe delays of indeterminate time.
function timer_thing():
set {_start} to now
set {task} to a task:
do nothing
# This task won't complete by itself
run {task}
broadcast "Quick! Step on stone!"
wait for {task}
# Waits until the task is completed remotely
broadcast "That took %time since {_start}%!"
{task} is completed # by the event below!
on step on stone:
complete {task} # Complete the task we started
Auto-completion
A task can be set to auto-complete when it reaches the end of its trigger.
Please note: this completion will occur the first time the task is delayed, stopped or suspended, rather than necessarily at the end of the section. It is just a safety measure for non-delayed tasks.
set {task} to an automatic task:
broadcast "hello"
run {task}
wait for {task} # Task completes itself
Cancellation
Like events, tasks can be 'cancelled'. This will wake up any trigger currently awaiting the task. Triggers will never wait for a cancelled task.
set {monitor me} to false
set {task} to a task:
wait 5 seconds
set {monitor me} to true
complete the current task
run {task}
{monitor me} is false
cancel {task}
{monitor me} is false
wait for {task} # Task is already 'cancelled', it will not be waited for!
{monitor me} is false
Cancellation will also attempt to stop the actual running of the task at a safe point.
set {task} to a task:
wait 5 seconds
kill {isaac}
complete the current task
run {task}
cancel {task} # Noo.. don't kill isaac!
{task} is cancelled
{isaac} is alive
Safe cancellation points currently include: delays, loops.
Cancellation and completion are the same, except that cancellation attempts to stop the task itself. You can check for cancellation and completion individually.
Related Issues: #6230, #5563
