I'd like to check if a range is within another ran...

# stdlib

[elect]

I'd like to check if a range is within another range, ie
i-2..i+2 in wd.indices

[ephemient]

there's two possible answers, both reasonable for different purposes:

this.start <= other.endInclusive && this.endInclusive >= other.start
this.start >= other.start && this.endInclusive <= other.endInclusive

plus additional considerations around what the result should be with empty ranges

[elect]

I don't see any reason why one would interpret this as the first option

[Ruckus]

I - 2 in wd.indices && I + 2 in wd.indices

[elect]

I'm doing exactly this atm

[lhwdev]

Thinking how operator in is implemented in Kotlin, it seems to imply that some element is contained in some *set*(collection), not subset. In java, there is containsAll, not contains.

[Klitos Kyriacou]

This would work but would currently be too expensive:

wd.indices.toSet().containsAll((i-2..i+2).toSet())

That's only because toSet() creates a LinkedHashSet. Perhaps it could be optimized to create a specialized Set that just keeps the range as its only property and whose contains method just forwards to the range, and defines a suitably specialized containsAll. Then the above code would have good performance.
Or perhaps just a new containsAll method on ranges.

[lhwdev]

Yes, sorry for not being clear. I meant contains (which corresponds to in) does not work for set-to-set. (like Set.contains(Set))