text: """
  class Ruler
  
  Helper class, used by [[MarkdownIt#core]], [[MarkdownIt#block]] and
  [[MarkdownIt#inline]] to manage sequences of functions (rules):
  
  - keep rules in defined order
  - assign the name to each rule
  - enable/disable rules
  - add/replace rules
  - allow assign rules to additional named chains (in the same)
  - cacheing lists of active rules
  
  You will not need use this class directly until write plugins. For simple
  rules control use [[MarkdownIt.disable]], [[MarkdownIt.enable]] and
  [[MarkdownIt.use]].
  """
  from typing import (
      Callable,
      Dict,
      Iterable,
      List,
      MutableMapping,
      Optional,
      Tuple,
      TYPE_CHECKING,
      Union,
  )
  import attr
  
  if TYPE_CHECKING:
      from markdown_it import MarkdownIt
  
  
  class StateBase:
      srcCharCode: Tuple[int, ...]
  
      def __init__(self, src: str, md: "MarkdownIt", env: MutableMapping):
          self.src = src
          self.env = env
          self.md = md
  
      @property
      def src(self) -> str:
          return self._src
  
      @src.setter
      def src(self, value: str) -> None:
          self._src = value
          self.srcCharCode = tuple(ord(c) for c in self.src)
  
  
  # The first positional arg is always a subtype of `StateBase`. Other
  # arguments may or may not exist, based on the rule's type (block,
  # core, inline). Return type is either `None` or `bool` based on the
  # rule's type.
  RuleFunc = Callable
  
  
  @attr.s(slots=True)
  class Rule:
      name: str = attr.ib()
      enabled: bool = attr.ib()
      fn: RuleFunc = attr.ib(repr=False)
      alt: List[str] = attr.ib()
  
  
  class Ruler:
      def __init__(self):
          # List of added rules.
          self.__rules__: List[Rule] = []
          # Cached rule chains.
          # First level - chain name, '' for default.
          # Second level - diginal anchor for fast filtering by charcodes.
          self.__cache__: Optional[Dict[str, List[RuleFunc]]] = None
  
      def __find__(self, name: str) -> int:
          """Find rule index by name"""
          for i, rule in enumerate(self.__rules__):
              if rule.name == name:
                  return i
          return -1
  
      def __compile__(self) -> None:
          """Build rules lookup cache"""
          chains = {""}
          # collect unique names
          for rule in self.__rules__:
              if not rule.enabled:
                  continue
              for name in rule.alt:
                  chains.add(name)
          self.__cache__ = {}
          for chain in chains:
              self.__cache__[chain] = []
              for rule in self.__rules__:
                  if not rule.enabled:
                      continue
                  if chain and (chain not in rule.alt):
                      continue
                  self.__cache__[chain].append(rule.fn)
  
      def at(self, ruleName: str, fn: RuleFunc, options=None):
          """Replace rule by name with new function & options.
  
          :param ruleName: rule name to replace.
          :param fn: new rule function.
          :param options: new rule options (not mandatory).
          :raises: KeyError if name not found
          """
          index = self.__find__(ruleName)
          options = options or {}
          if index == -1:
              raise KeyError(f"Parser rule not found: {ruleName}")
          self.__rules__[index].fn = fn
          self.__rules__[index].alt = options.get("alt", [])
          self.__cache__ = None
  
      def before(self, beforeName: str, ruleName: str, fn: RuleFunc, options=None):
          """Add new rule to chain before one with given name.
  
          :param beforeName: new rule will be added before this one.
          :param ruleName: new rule will be added before this one.
          :param fn: new rule function.
          :param options: new rule options (not mandatory).
          :raises: KeyError if name not found
          """
          index = self.__find__(beforeName)
          options = options or {}
          if index == -1:
              raise KeyError(f"Parser rule not found: {beforeName}")
          self.__rules__.insert(index, Rule(ruleName, True, fn, options.get("alt", [])))
          self.__cache__ = None
  
      def after(self, afterName: str, ruleName: str, fn: RuleFunc, options=None):
          """Add new rule to chain after one with given name.
  
          :param afterName: new rule will be added after this one.
          :param ruleName: new rule will be added after this one.
          :param fn: new rule function.
          :param options: new rule options (not mandatory).
          :raises: KeyError if name not found
          """
          index = self.__find__(afterName)
          options = options or {}
          if index == -1:
              raise KeyError(f"Parser rule not found: {afterName}")
          self.__rules__.insert(
              index + 1, Rule(ruleName, True, fn, options.get("alt", []))
          )
          self.__cache__ = None
  
      def push(self, ruleName: str, fn: RuleFunc, options=None):
          """Push new rule to the end of chain.
  
          :param ruleName: new rule will be added to the end of chain.
          :param fn: new rule function.
          :param options: new rule options (not mandatory).
  
          """
          self.__rules__.append(Rule(ruleName, True, fn, (options or {}).get("alt", [])))
          self.__cache__ = None
  
      def enable(self, names: Union[str, Iterable[str]], ignoreInvalid: bool = False):
          """Enable rules with given names.
  
          :param names: name or list of rule names to enable.
          :param ignoreInvalid: ignore errors when rule not found
          :raises: KeyError if name not found and not ignoreInvalid
          :return: list of found rule names
          """
          if isinstance(names, str):
              names = [names]
          result = []
          for name in names:
              idx = self.__find__(name)
              if (idx < 0) and ignoreInvalid:
                  continue
              if (idx < 0) and not ignoreInvalid:
                  raise KeyError(f"Rules manager: invalid rule name {name}")
              self.__rules__[idx].enabled = True
              result.append(name)
          self.__cache__ = None
          return result
  
      def enableOnly(self, names: Union[str, Iterable[str]], ignoreInvalid: bool = False):
          """Enable rules with given names, and disable everything else.
  
          :param names: name or list of rule names to enable.
          :param ignoreInvalid: ignore errors when rule not found
          :raises: KeyError if name not found and not ignoreInvalid
          :return: list of found rule names
          """
          if isinstance(names, str):
              names = [names]
          for rule in self.__rules__:
              rule.enabled = False
          self.enable(names, ignoreInvalid)
  
      def disable(self, names: Union[str, Iterable[str]], ignoreInvalid: bool = False):
          """Disable rules with given names.
  
          :param names: name or list of rule names to enable.
          :param ignoreInvalid: ignore errors when rule not found
          :raises: KeyError if name not found and not ignoreInvalid
          :return: list of found rule names
          """
          if isinstance(names, str):
              names = [names]
          result = []
          for name in names:
              idx = self.__find__(name)
              if (idx < 0) and ignoreInvalid:
                  continue
              if (idx < 0) and not ignoreInvalid:
                  raise KeyError(f"Rules manager: invalid rule name {name}")
              self.__rules__[idx].enabled = False
              result.append(name)
          self.__cache__ = None
          return result
  
      def getRules(self, chainName: str) -> List[RuleFunc]:
          """Return array of active functions (rules) for given chain name.
          It analyzes rules configuration, compiles caches if not exists and returns result.
  
          Default chain name is `''` (empty string). It can't be skipped.
          That's done intentionally, to keep signature monomorphic for high speed.
  
          """
          if self.__cache__ is None:
              self.__compile__()
              assert self.__cache__ is not None
          # Chain can be empty, if rules disabled. But we still have to return Array.
          return self.__cache__.get(chainName, []) or []
  
      def get_all_rules(self) -> List[str]:
          """Return all available rule names."""
          return [r.name for r in self.__rules__]
  
      def get_active_rules(self) -> List[str]:
          """Return the active rule names."""
          return [r.name for r in self.__rules__ if r.enabled]
  