def dkeyspan

mylsm-lsm-store@0.3.2.0 · src/Wal.bend:350

import Base

350# DKEY take: mirror for delete keys.
351def dkeyspan(
352  key: String,
353  +kacc0: String,
354  tail: String,
355  muts0: List<&2, Mut>,
356  tag: Char,
357) -> {dec_run(String.length(key ++ tail), key ++ tail, DS{DKey{}, muts0, tag, String.length(key), kacc0, "", "", True{}}) == dec_run(String.length(tail), tail, DS{DKey{}, muts0, tag, 0n, kacc0 ++ key, "", "", True{}}) : DecState}:
358  match key:
359    case SNil{}:
360      %Equal.sym(String, kacc0 ++ "", kacc0, app_nil_r(kacc0)) : {dec_run(String.length(tail), tail, DS{DKey{}, muts0, tag, 0n, kacc0, "", "", True{}}) == dec_run(String.length(tail), tail, DS{DKey{}, muts0, tag, 0n, _, "", "", True{}}) : DecState}
361      {==}
362    case SCon{+h, +t}:
363      %app_assoc(kacc0, SCon{h, SNil{}}, t) : {dec_run(String.length(t ++ tail), t ++ tail, DS{DKey{}, muts0, tag, String.length(t), kacc0 ++ SCon{h, SNil{}}, "", "", True{}}) == dec_run(String.length(tail), tail, DS{DKey{}, muts0, tag, 0n, _, "", "", True{}}) : DecState}
364      %dkeyspan(t, kacc0 ++ SCon{h, SNil{}}, tail, muts0, tag) : {dec_run(String.length(t ++ tail), t ++ tail, DS{DKey{}, muts0, tag, String.length(t), kacc0 ++ SCon{h, SNil{}}, "", "", True{}}) == _ : DecState}
365      {==}