Is it possible to somehow create a sequence from inside of a `DeepRecursiveFunction` ```fun s = sequence lt Int gt val f = DeepRecursiveFunction lt Int Unit gt yield it Compile error Restricted suspending functions can only invoke member or extension suspending functions on their restricted coroutine scope if it lt 1000 callRecursive it + 1 f 1 ```

fun s() = sequence<Int> { 
    val f = DeepRecursiveFunction<Int, Unit> {
        yield(it) // Compile error: Restricted suspending functions can only invoke member or extension suspending functions on their restricted coroutine scope
        
        if (it < 1000) {
            callRecursive(it + 1)
        }
    }
    
    f(1)
}

ephemient

04/11/2023, 7:26 AM

no, it's there for a reason. SequenceScope and DeepRecursiveScope handle suspension differently and don't mix

even if you

@Suppress("ILLEGAL_RESTRICTED_SUSPENDING_FUNCTION_CALL")

to bypass the compiler error, it won't work

it doesn't even work with the same type of scope, e.g.

sequence outer@{
    sequence inner@{
        this@outer.yield(Unit)
    }
}

it has to be the actual same scope under

@RestrictsSuspension

Norbi

04/11/2023, 7:51 AM

OK, thanks.

ephemient

04/11/2023, 8:40 PM

btw you don't need DeepRecursiveFunction here anyway. the sequence builder is transformed by the compiler into a state machine just other suspend functions

private fun f(n: Int): Sequence<Int> = sequence {
    yield(n)

    if (n < 1000) {
        yieldAll(f(n + 1))
    }
}

fun s(): Sequence<Int> = f(1)

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