1"""Lazy regex compilation helper used outside of URL routing."""
 2
 3from __future__ import annotations
 4
 5import re
 6
 7from plain.utils.functional import SimpleLazyObject
 8
 9
10def _lazy_re_compile(
11    regex: str | bytes | re.Pattern[str] | re.Pattern[bytes], flags: int = 0
12) -> SimpleLazyObject:
13    """Lazily compile a regex with flags."""
14
15    def _compile() -> re.Pattern[str] | re.Pattern[bytes]:
16        if isinstance(regex, str | bytes):
17            return re.compile(regex, flags)
18        else:
19            assert not flags, "flags must be empty if regex is passed pre-compiled"
20            return regex
21
22    return SimpleLazyObject(_compile)