Function read

trace_back.py:154–195

(q: problem.Dependency)

  stack = []

  def read(q: problem.Dependency) -> None:
    q = q.remove_loop()
    hashed = q.hashed()
    if hashed in visited:
      return

    if hashed[0] in ['ncoll', 'npara', 'nperp', 'diff', 'sameside']:
      return

    nonlocal stack

    stack.append(hashed)
    prems = []

    if q.rule_name != problem.CONSTRUCTION_RULE:
      all_deps = []
      dep_names = set()
      for d in q.why:
        if d.hashed() in dep_names:
          continue
        dep_names.add(d.hashed())
        all_deps.append(d)

      for d in all_deps:
        h = d.hashed()
        if h not in visited:
          read(d)
        if h in visited:
          prems.append(d)

    visited.add(hashed)
    hashs = sorted([d.hashed() for d in prems])
    found = False
    for ps, qs in log:
      if sorted([d.hashed() for d in ps]) == hashs:
        qs += [q]
        found = True
        break
    if not found:
      log.append((prems, [q]))

    stack.pop(-1)

  read(query)