AxisAlgebra.lookup_naturals: def of bendtorch-core@0.1.0.0
Import: import bendtorch-core@0.1.0.0/src/tensor/axis_algebra.bend as AxisAlgebra
Lines 259-269 of bendtorch-core@0.1.0.0/src/tensor/axis_algebra.bend: https://jend.leeeet.dev/read.txt?path=bendtorch-core@0.1.0.0/src/tensor/axis_algebra.bend&start_line=259&end_line=269

import Base
import bendtorch-core@0.1.0.0/src/shape/core.bend as Shape
import bendtorch-core@0.1.0.0/src/tensor/axis_spec.bend as Axis

def lookup_naturals(+items: List<&2, U32>, +index: Nat) ->
  {natural_value(Axis.lookup(U32, items, index)) == Axis.lookup(Nat, Shape.naturals(items), index) : Maybe<&2, Nat>}:
  match items index:
    case Nil{} 0n:
      {==}
    case Nil{} 1n+p:
      {==}
    case head <> tail 0n:
      {==}
    case head <> +tail 1n+p:
      lookup_naturals(tail, p)

Uses (7):
  https://jend.leeeet.dev/definition.txt?path=Base/base.bend&name=List
  https://jend.leeeet.dev/definition.txt?path=Base/base.bend&name=Maybe
  https://jend.leeeet.dev/definition.txt?path=Base/base.bend&name=Nat
  https://jend.leeeet.dev/definition.txt?path=Base/base.bend&name=U32
  https://jend.leeeet.dev/definition.txt?path=bendtorch-core@0.1.0.0/src/shape/core.bend&name=naturals
  https://jend.leeeet.dev/definition.txt?path=bendtorch-core@0.1.0.0/src/tensor/axis_algebra.bend&name=natural_value
  https://jend.leeeet.dev/definition.txt?path=bendtorch-core@0.1.0.0/src/tensor/axis_spec.bend&name=lookup