def fold

stelliferous@0.0.2.0 · proofs/traversal_certificate.bend:43

import Base
import stelliferous@0.0.2.0/traversal_array.bend as Traversal
import stelliferous@0.0.2.0/proofs/traversal_witness.bend as TraversalWitness

43def fold(~Reader: Type,~Element: Data,~Accumulator: Data,~Context: Data,~ReaderCertificate: @-reader: Reader -> Data,
44  ~ReaderEvidence: @-reader: Reader -> Data,~witness: @-reader: Reader -> ReaderCertificate(reader) -> ReaderEvidence(reader),
45  ~read: Reader -> Context -> U32 -> Reader & Element,~combine: Accumulator -> Element -> Accumulator,
46  ~read_preserves: @-reader: Reader -> @context: Context -> @index: U32 -> ReaderEvidence(reader) ->
47    TraversalWitness.Sample<Reader,Element,reader,read(reader,context,index)>,
48  count: Nat,position: U32,context: Context,-reader: Reader,-initial: Accumulator,+certificate: ReaderCertificate(reader)) ->
49  ReaderCertificate(TraversalWitness.first(~Reader,~Accumulator,Traversal.fold(~Reader,~Element,~Accumulator,~Context,~read,~combine,count,position,reader,initial,context))):
50  %Equal.sym(Reader,TraversalWitness.first(~Reader,~Accumulator,Traversal.fold(~Reader,~Element,~Accumulator,~Context,~read,~combine,count,position,reader,initial,context)),reader,
51    TraversalWitness.fold(~Reader,~Element,~Accumulator,~Context,~ReaderEvidence,~read,~combine,~read_preserves,
52      count,reader,position,context,initial,witness(reader,certificate))) : ReaderCertificate(_)
53  certificate