Stream: contributing

Topic: List.insert / intersperse (#9596)

Dzmitry Misiuk (Jul 24 2026 at 14:33):

Two more small pure-Roc List builtins from #9596:

• insert : List(a), U64, a -> Try(List(a), [OutOfBounds, ..]) — insert an element at an index, Try-returning
• intersperse : List(a), a -> List(a) — put a separator between elements

Both pure Roc over existing primitives, no new low-level ops. Planning insert as one small PR and intersperse as another — and for intersperse, shout if you'd rather see it as an Iter helper than a List one.

Dzmitry Misiuk (Jul 24 2026 at 16:33):

insert is up as #10359. Holding intersperse for now — shout if you'd rather it be an Iter helper, otherwise I'll open it too.

Last updated: Aug 12 2026 at 12:35 UTC