97 lines
3.0 KiB
Python
97 lines
3.0 KiB
Python
"""符文引擎核心：解析 ``{{...}}`` 占位符并替换。
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纯逻辑，无 IO、无代码执行——与酒馆可执行脚本的 macro 引擎划清边界：
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魂镜的符文只做文本替换，宏的解析器是受信任的 Python 函数，绝不 eval 用户输入。
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规则：
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- 未知宏保留原 ``{{...}}`` 文本（不静默清空，避免误删用户文本）。
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- 解析器抛异常时保留原 ``{{...}}`` 文本，不阻断文本流。
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- 递归展开受限深度（``max_depth``），防止 ``{{a}}→{{b}}→{{a}}`` 振荡死循环。
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"""
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from __future__ import annotations
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import re
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from collections.abc import Callable
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from app.modules.macros.types import MacroContext
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MacroResolver = Callable[[list[str], MacroContext], str]
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_MACRO_PATTERN = re.compile(r"\{\{(.*?)\}\}")
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_DEFAULT_MAX_DEPTH = 5
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class MacroRegistry:
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"""符文注册表：名称（大小写不敏感）→ 解析器。"""
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def __init__(self) -> None:
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self._macros: dict[str, MacroResolver] = {}
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def register(self, name: str, resolver: MacroResolver) -> None:
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self._macros[name.casefold()] = resolver
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def get(self, name: str) -> MacroResolver | None:
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return self._macros.get(name.casefold())
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def names(self) -> tuple[str, ...]:
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return tuple(self._macros)
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def render(
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text: str,
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ctx: MacroContext,
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*,
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registry: MacroRegistry | None = None,
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max_depth: int = _DEFAULT_MAX_DEPTH,
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) -> str:
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"""把 ``text`` 中的 ``{{...}}`` 占位符按 ``registry`` 替换。
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递归展开（宏的返回值可含新的 ``{{...}}``），直到无占位符或达 ``max_depth``。
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未提供 ``registry`` 时使用内置默认符文集。
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"""
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reg = registry if registry is not None else _default_registry_lazy()
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current = text
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for _ in range(max_depth):
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if "{{" not in current:
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break
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nxt = _render_once(current, reg, ctx)
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if nxt == current:
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break
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current = nxt
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return current
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def _render_once(text: str, reg: MacroRegistry, ctx: MacroContext) -> str:
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def _replace(match: re.Match[str]) -> str:
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body = match.group(1).strip()
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if not body:
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return match.group(0)
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name, args = _split_macro(body)
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resolver = reg.get(name)
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if resolver is None:
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return match.group(0)
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try:
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return resolver(args, ctx)
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except Exception:
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return match.group(0)
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return _MACRO_PATTERN.sub(_replace, text)
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def _split_macro(body: str) -> tuple[str, list[str]]:
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"""``name:arg1,arg2`` → ``("name", ["arg1", "arg2"])``；无参数时 args 为空。"""
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if ":" in body:
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name, rest = body.split(":", 1)
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args = [a.strip() for a in rest.split(",") if a.strip()] if rest.strip() else []
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else:
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name, args = body, []
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return name.strip(), args
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def _default_registry_lazy() -> MacroRegistry:
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"""延迟构造内置符文集，避免与 builtins 循环导入。"""
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from app.modules.macros.builtins import build_default_registry
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return build_default_registry()
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