def path

bolt@1.27.0.0 · src/lsp/semantic.bend:143

import Base

143# a key's way down the index: its low bits, lowest first
144def path(dd: Nat, +key: U32) -> List<&2, Bool>:
145  match dd:
146    case 0n:
147      Nil{}
148    case 1n+p:
149      U32.is_even(key) <> path(p, U32.shr(key))