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#coroutines
Title
# coroutines
v

vineethraj49

02/13/2020, 7:59 PM
what is the difference between the 
block: suspend () -> T
and 
block: suspend CoroutineScope.() -> T
types?
o

octylFractal

02/13/2020, 8:02 PM
the second one is usually improper, as it passes two contexts down to the function -- the 
suspend
one and the 
CoroutineScope
one -- and it's not clear which one will be used
usually you'd stick with either 
suspend () -> T
, indicating that it's a normal suspend function that will actually suspend while doing work, or with 
CoroutineScope.() -> T
, which indicates that it will launch a separate coroutine that won't suspend this codepath. usually 
T
will contain some reference to the Job that was started in this case.
e

Evan R.

02/13/2020, 8:04 PM
The second one could potentially let the suspending function launch coroutines into your current scope. The first one will force 
block()
to use 
coroutineScope {}
to launch its coroutines and therefore all launched coroutines in 
block()
are guaranteed to complete with that signature
l

louiscad

02/15/2020, 8:04 AM
@octylFractal The second one is absolutely NOT improper. That's the signature of 
launch
, 
async
and 
coroutineScope
lambdas. If a custom function creates an inner scope as well, it's totally okay, it's totally to have the lambda(s) have that signature.
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