TensorBackwardLAWS.sole: def of bendtorch-core@0.1.0.0
Import: import bendtorch-core@0.1.0.0/src/autograd/tensor_backward_LAWS.bend as TensorBackwardLAWS
Lines 107-118 of bendtorch-core@0.1.0.0/src/autograd/tensor_backward_LAWS.bend: https://jend.leeeet.dev/read.txt?path=bendtorch-core@0.1.0.0/src/autograd/tensor_backward_LAWS.bend&start_line=107&end_line=118

import Base
import bendtorch-core@0.1.0.0/src/autograd/tensor_backward.bend as Backward

# The only contribution of a VJP, when it sends exactly one.
def sole(pass: Backward.Pass) -> Maybe<&1, Backward.Contribution>:
  Backward.Pass{saved, g, contributions} = pass
  match contributions:
    case Fail{error}:
      None{}
    case Done{Nil{}}:
      None{}
    case Done{Con{contribution, Nil{}}}:
      Some{contribution}
    case Done{Con{contribution, Con{other, rest}}}:
      None{}

Uses (5):
  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=Result
  https://jend.leeeet.dev/definition.txt?path=bendtorch-core@0.1.0.0/src/autograd/tensor_backward.bend&name=Contribution
  https://jend.leeeet.dev/definition.txt?path=bendtorch-core@0.1.0.0/src/autograd/tensor_backward.bend&name=Pass