Perm.odds: def of bend-mathlib@0.8.1.0
Import: import bend-mathlib@0.8.1.0/perm.bend as Perm
Lines 201-211 of bend-mathlib@0.8.1.0/perm.bend: https://jend.leeeet.dev/read.txt?path=bend-mathlib@0.8.1.0/perm.bend&start_line=201&end_line=211

import Base

# The elements of a list at odd positions (1, 3, 5, ...).
def odds(-A: Data, xs: List<&2, A>) -> List<&2, A>:
  match xs:
    case Nil{}:
      Nil{}
    case +x <> r:
      match r:
        case Nil{}:
          Nil{}
        case +y <> t:
          y <> odds(A, t)

Uses (1):
  https://jend.leeeet.dev/definition.txt?path=Base/base.bend&name=List