from __future__ import annotations from collections.abc import Iterable, Iterator from functools import lru_cache from typing import TYPE_CHECKING, Callable, TypeVar, Union, overload import jaraco.text as text from packaging.requirements import Requirement if TYPE_CHECKING: from typing_extensions import TypeAlias _T = TypeVar("_T") _StrOrIter: TypeAlias = Union[str, Iterable[str]] parse_req: Callable[[str], Requirement] = lru_cache()(Requirement) # Setuptools parses the same requirement many times # (e.g. first for validation than for normalisation), # so it might be worth to cache. def parse_strings(strs: _StrOrIter) -> Iterator[str]: """ Yield requirement strings for each specification in `strs`. `strs` must be a string, or a (possibly-nested) iterable thereof. """ return text.join_continuation(map(text.drop_comment, text.yield_lines(strs))) # These overloads are only needed because of a mypy false-positive, pyright gets it right # https://github.com/python/mypy/issues/3737 @overload def parse(strs: _StrOrIter) -> Iterator[Requirement]: ... @overload def parse(strs: _StrOrIter, parser: Callable[[str], _T]) -> Iterator[_T]: ... def parse(strs: _StrOrIter, parser: Callable[[str], _T] = parse_req) -> Iterator[_T]: # type: ignore[assignment] """ Parse requirements. """ return map(parser, parse_strings(strs))