TraversalWitness.fold: def of stelliferous@0.0.2.0
Import: import stelliferous@0.0.2.0/proofs/traversal_witness.bend as TraversalWitness
Lines 277-287 of stelliferous@0.0.2.0/proofs/traversal_witness.bend: https://jend.leeeet.dev/read.txt?path=stelliferous@0.0.2.0/proofs/traversal_witness.bend&start_line=277&end_line=287

import Base
import stelliferous@0.0.2.0/traversal_loop.bend as Loop
import stelliferous@0.0.2.0/traversal_array.bend as Traversal

def fold(~Reader: Type,~Element: Data,~Accumulator: Data,~Context: Data,~ReaderEvidence: @-reader: Reader -> Data,
  ~read: Reader -> Context -> U32 -> Reader & Element,~combine: Accumulator -> Element -> Accumulator,
  ~read_preserves: @-reader: Reader -> @context: Context -> @index: U32 -> ReaderEvidence(reader) ->
    Sample<Reader,Element,reader,read(reader,context,index)>,
  count: Nat,-reader: Reader,position: U32,context: Context,-initial: Accumulator,reader_evidence: ReaderEvidence(reader)) ->
  {first(~Reader,~Accumulator,Traversal.fold(~Reader,~Element,~Accumulator,~Context,~read,~combine,count,position,reader,initial,context)) == reader : Reader}:
  fold_finished(~Reader,~Accumulator,~Context,reader,
    Loop.run(~Traversal.State<&1,&2,Reader,Accumulator,Context>,~Traversal.fold_step(~Reader,~Element,~Accumulator,~Context,~read,~combine),count,
      Traversal.State{reader,initial,position,context}),
    fold_run(~Reader,~Element,~Accumulator,~Context,~ReaderEvidence,~read,~combine,~read_preserves,count,reader,
      Traversal.State{reader,initial,position,context},reader_evidence,FoldEvidence{initial,position,context,{==}}))

Uses (12):
  https://jend.leeeet.dev/definition.txt?path=Base/base.bend&name=Nat
  https://jend.leeeet.dev/definition.txt?path=Base/base.bend&name=Pair
  https://jend.leeeet.dev/definition.txt?path=Base/base.bend&name=U32
  https://jend.leeeet.dev/definition.txt?path=stelliferous@0.0.2.0/proofs/traversal_witness.bend&name=FoldEvidence
  https://jend.leeeet.dev/definition.txt?path=stelliferous@0.0.2.0/proofs/traversal_witness.bend&name=Sample
  https://jend.leeeet.dev/definition.txt?path=stelliferous@0.0.2.0/proofs/traversal_witness.bend&name=first
  https://jend.leeeet.dev/definition.txt?path=stelliferous@0.0.2.0/proofs/traversal_witness.bend&name=fold_finished
  https://jend.leeeet.dev/definition.txt?path=stelliferous@0.0.2.0/proofs/traversal_witness.bend&name=fold_run
  https://jend.leeeet.dev/definition.txt?path=stelliferous@0.0.2.0/traversal_array.bend&name=State
  https://jend.leeeet.dev/definition.txt?path=stelliferous@0.0.2.0/traversal_array.bend&name=fold
  https://jend.leeeet.dev/definition.txt?path=stelliferous@0.0.2.0/traversal_array.bend&name=fold_step
  https://jend.leeeet.dev/definition.txt?path=stelliferous@0.0.2.0/traversal_loop.bend&name=run