List.set: def of Base
Import: import Base
Lines 1001-1008 of Base/base.bend: https://jend.leeeet.dev/read.txt?path=Base/base.bend&start_line=1001&end_line=1008

import Base

def List.set(a, -A: Kind(a), xs: List<a, A>, n: Nat, x: A) -> List<a, A>:
  match xs n:
    case Nil{} _:
      Nil{}
    case h <> t 0n:
      x <> t
    case h <> t 1n+p:
      h <> List.set(a, A, t, p, x)

Uses (2):
  https://jend.leeeet.dev/definition.txt?path=Base/base.bend&name=List
  https://jend.leeeet.dev/definition.txt?path=Base/base.bend&name=Nat