ReduceFoldLAWS.ReduceToContract: type of bendtorch-core@0.1.0.0
Import: import bendtorch-core@0.1.0.0/src/autograd/reduce_fold_LAWS.bend as ReduceFoldLAWS
Lines 62-73 of bendtorch-core@0.1.0.0/src/autograd/reduce_fold_LAWS.bend: https://jend.leeeet.dev/read.txt?path=bendtorch-core@0.1.0.0/src/autograd/reduce_fold_LAWS.bend&start_line=62&end_line=73

import Base
import bendtorch-core@0.1.0.0/src/shape/core.bend as Shape
import bendtorch-core@0.1.0.0/src/tensor/core.bend as Core
import bendtorch-core@0.1.0.0/src/autograd/reduce.bend as Reduce
import bendtorch-core@0.1.0.0/src/autograd/reduce_LAWS.bend as ReduceLaws

# What reduce_to promises, stated only through the result: it succeeds with
# the target's dimensions, every in-bounds target cell holds `expected`, and
# the returned contribution still holds every word.
type ReduceToContract<-target: Shape.Shape, -input: Shape.Shape, -expected: U32 -> Maybe<&2, F32>, -word: U32 -> F32,
  -result: Core.Dynamic & Result<&2, &1, Reduce.Error, Core.Dynamic>> is Type:
  ReduceToContract{
    successful: {ReduceLaws.succeeded(result) == True{} : Bool},
    dimensions: {output_dimensions(result) == Some{Shape.dimensions(target)} : Maybe<&2, List<&2, U32>>},
    value: @+index: U32 -> @inside: {Nat.is_lt(U32.to_nat(index), Shape.logical_numel(Shape.dimensions(target))) == True{} : Bool} ->
      {output_point(result, index) == expected(index) : Maybe<&2, F32>},
    kept: @+other: U32 -> @inside: {Nat.is_lt(U32.to_nat(other), Shape.logical_numel(Shape.dimensions(input))) == True{} : Bool} ->
      {input_point(result, other) == Some{word(other)} : Maybe<&2, F32>}}

Uses (18):
  https://jend.leeeet.dev/definition.txt?path=Base/base.bend&name=Bool
  https://jend.leeeet.dev/definition.txt?path=Base/base.bend&name=F32
  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.is_lt
  https://jend.leeeet.dev/definition.txt?path=Base/base.bend&name=Pair
  https://jend.leeeet.dev/definition.txt?path=Base/base.bend&name=Result
  https://jend.leeeet.dev/definition.txt?path=Base/base.bend&name=U32
  https://jend.leeeet.dev/definition.txt?path=Base/base.bend&name=U32.to_nat
  https://jend.leeeet.dev/definition.txt?path=bendtorch-core@0.1.0.0/src/autograd/reduce.bend&name=Error
  https://jend.leeeet.dev/definition.txt?path=bendtorch-core@0.1.0.0/src/autograd/reduce_LAWS.bend&name=succeeded
  https://jend.leeeet.dev/definition.txt?path=bendtorch-core@0.1.0.0/src/autograd/reduce_fold_LAWS.bend&name=input_point
  https://jend.leeeet.dev/definition.txt?path=bendtorch-core@0.1.0.0/src/autograd/reduce_fold_LAWS.bend&name=output_dimensions
  https://jend.leeeet.dev/definition.txt?path=bendtorch-core@0.1.0.0/src/autograd/reduce_fold_LAWS.bend&name=output_point
  https://jend.leeeet.dev/definition.txt?path=bendtorch-core@0.1.0.0/src/shape/core.bend&name=Shape
  https://jend.leeeet.dev/definition.txt?path=bendtorch-core@0.1.0.0/src/shape/core.bend&name=dimensions
  https://jend.leeeet.dev/definition.txt?path=bendtorch-core@0.1.0.0/src/shape/core.bend&name=logical_numel
  https://jend.leeeet.dev/definition.txt?path=bendtorch-core@0.1.0.0/src/tensor/core.bend&name=Dynamic