def truncate_view.go

lawful-bytes@0.1.1.0 · PROOF.bend:317

import Base
import lawful-bytes@0.1.1.0/defs.bend as D
import lawful-bytes@0.1.1.0/bytes.bend as B
import lawful-bytes@0.1.1.0/proof_core.bend as C
import lawful-bytes@0.1.1.0/proof_ops.bend as O

317def truncate_view.go(-b: D.Bytes, +n: U32, h: {Nat.is_le(U32.to_nat(n), D.size(b)) == True{} : Bool}, m_b: C.BMirror(b)) ->
318  {D.view(B.truncate(b, n)) == List.take(&2, U32, D.view(b), U32.to_nat(n)) : List<&2, U32>}:
319  (+l_b, m2_b) = m_b
320  (+t_b, +e_b) = m2_b
321  %e_b : {D.view(B.truncate(_, n)) == List.take(&2, U32, D.view(_), U32.to_nat(n)) : List<&2, U32>}
322  +h_t = C.tr(x => {Nat.is_le(U32.to_nat(n), D.size(x)) == True{} : Bool}, b, l_b, t_b, e_b, h)
323  O.truncate_view_t(l_b, t_b, n, h_t)