@default_drive.make_event
async def start(event: EventInput, global_ctx):
    print("start")
    
@default_drive.listen_group([start])
async def hello(event: EventInput, global_ctx):
    return 1


@default_drive.listen_group([start])
async def world(event: EventInput, global_ctx):
    return 2


@default_drive.listen_group([hello, world])
async def adding(event: EventInput, global_ctx):
    results = event.results
    print("adding", hello, world)
    return results[hello.id] + results[world.id]


results = asyncio.run(default_drive.invoke_event(start))
assert results[adding.id] == 3

adding will be triggered at first time as long as hello and world are done.

@default_drive.make_event
async def start(event: EventInput, global_ctx):
    print("start")

@default_drive.listen_group([start])
async def hello(event: EventInput, global_ctx):
    print(datetime.now(), "hello")
    await asyncio.sleep(0.2)
    print(datetime.now(), "hello done")


@default_drive.listen_group([start])
async def world(event: EventInput, global_ctx):
    print(datetime.now(), "world")
    await asyncio.sleep(0.2)
    print(datetime.now(), "world done")

asyncio.run(default_drive.invoke_event(start))

from drive_flow.dynamic import abort_this

@default_drive.make_event
async def a(event: EventInput, global_ctx):
    return abort_this()
# abort_this is not exiting the whole workflow,
# only abort this event's return and not causing any other influence
# `a` chooses to abort its return. So no more events in this invoking.
# this invoking then will end
@default_drive.listen_group([a])
async def b(event: EventInput, global_ctx):
    assert False, "should not be called"
    
asyncio.run(default_drive.invoke_event(a))

from drive_flow.types import ReturnBehavior
from drive_flow.dynamic import goto_events, abort_this

call_a_count = 0
@default_drive.make_event
async def a(event: EventInput, global_ctx):
    global call_a_count
    if call_a_count == 0:
        assert event is None
    elif call_a_count == 1:
        assert event.behavior == ReturnBehavior.GOTO
        assert event.results == {b.id: 2}
        return abort_this()
    call_a_count += 1
    return 1

@default_drive.listen_group([a])
async def b(event: EventInput, global_ctx):
    return goto_events([a], 2)

@default_drive.listen_group([b])
async def c(event: EventInput, global_ctx):
    assert False, "should not be called"
    
asyncio.run(default_drive.invoke_event(a))