"""
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)
- caching 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 __future__ import annotations
from collections.abc import Callable, Iterable, MutableMapping
from dataclasses import dataclass, field
from typing import TYPE_CHECKING
from markdown_it._compat import DATACLASS_KWARGS
if TYPE_CHECKING:
from markdown_it import MarkdownIt
[docs]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
[docs]@dataclass(**DATACLASS_KWARGS)
class Rule:
name: str
enabled: bool
fn: RuleFunc = field(repr=False)
alt: list[str]
[docs]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__: dict[str, list[RuleFunc]] | None = 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)
[docs] 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
[docs] 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
[docs] 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
[docs] 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
[docs] def enable(self, names: 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
[docs] def enableOnly(self, names: 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)
[docs] def disable(self, names: 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
[docs] 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 []
[docs] def get_all_rules(self) -> list[str]:
"""Return all available rule names."""
return [r.name for r in self.__rules__]
[docs] def get_active_rules(self) -> list[str]:
"""Return the active rule names."""
return [r.name for r in self.__rules__ if r.enabled]