What does KMathContext do?

[lounres]

There is annotation class KMathContext in kmath-core/src/commonMain/kotlin/space/kscience/kmath/operations/Algebra.kt that is not used anywhere. (All appearances of word "KMathContext" are only declarations of the class in .kt sources, .api dump file and diagram in docs.) Is there really any functionality behind it?

[altavir]

KMathContext is a marker for https://kotlinlang.org/api/latest/jvm/stdlib/kotlin/-dsl-marker/ functionality. Used to prohibit implicit scope propagation inside inner scope. Basically if for some reason we have two different scopes of the same type on inside another we do not want to occasionally call outer one. The DslMarker is not quite stright-forward, but I hope it will be clearer in future.

[lounres]

Well, I already know what DSL marker annotations are. (I have fully read Kotlin in Action, where they are well described.) The question is not about DslMarker but KMathContext (and functionality not of DslMarker but of KMathContext).

To use mechanism of DSL markers you must apply the markers at least once. But there is no usage of KMathContext. It's just declared, marked as DSL marker and not used. There is no actual appearance of the annotation in Kotline sources except declaration of the annotation class.

So I ask what there is unused annotation class for.

[altavir]

Obviously because somebody forgot to use it or used at some moment and then stopped using it. It happens with research libraries :)

[altavir]

An additional benefit is that functions marked with DslMarker are highlighted in Idea