晋太元中,武陵人捕鱼为业。缘溪行,忘路之远近。忽逢桃花林,夹岸数百步,中无杂树,芳草鲜美,落英缤纷。渔人甚异之,复前行,欲穷其林。 林尽水源,便得一山,山有小口,仿佛若有光。便舍船,从口入。初极狭,才通人。复行数十步,豁然开朗。土地平旷,屋舍俨然,有良田、美池、桑竹之属。阡陌交通,鸡犬相闻。其中往来种作,男女衣着,悉如外人。黄发垂髫,并怡然自乐。 见渔人,乃大惊,问所从来。具答之。便要还家,设酒杀鸡作食。村中闻有此人,咸来问讯。自云先世避秦时乱,率妻子邑人来此绝境,不复出焉,遂与外人间隔。问今是何世,乃不知有汉,无论魏晋。此人一一为具言所闻,皆叹惋。余人各复延至其家,皆出酒食。停数日,辞去。此中人语云:“不足为外人道也。”(间隔 一作:隔绝) 既出,得其船,便扶向路,处处志之。及郡下,诣太守,说如此。太守即遣人随其往,寻向所志,遂迷,不复得路。 南阳刘子骥,高尚士也,闻之,欣然规往。未果,寻病终。后遂无问津者。
| DIR:/opt/alt/python27/lib/python2.7/site-packages/pip/_internal/resolution/resolvelib/ |
| Current File : //opt/alt/python27/lib/python2.7/site-packages/pip/_internal/resolution/resolvelib/base.py |
from pip._vendor.packaging.specifiers import SpecifierSet
from pip._vendor.packaging.utils import canonicalize_name
from pip._internal.req.req_install import InstallRequirement
from pip._internal.utils.hashes import Hashes
from pip._internal.utils.typing import MYPY_CHECK_RUNNING
if MYPY_CHECK_RUNNING:
from typing import FrozenSet, Iterable, Optional, Tuple
from pip._vendor.packaging.version import _BaseVersion
from pip._internal.models.link import Link
CandidateLookup = Tuple[
Optional["Candidate"],
Optional[InstallRequirement],
]
def format_name(project, extras):
# type: (str, FrozenSet[str]) -> str
if not extras:
return project
canonical_extras = sorted(canonicalize_name(e) for e in extras)
return "{}[{}]".format(project, ",".join(canonical_extras))
class Constraint(object):
def __init__(self, specifier, hashes):
# type: (SpecifierSet, Hashes) -> None
self.specifier = specifier
self.hashes = hashes
@classmethod
def empty(cls):
# type: () -> Constraint
return Constraint(SpecifierSet(), Hashes())
@classmethod
def from_ireq(cls, ireq):
# type: (InstallRequirement) -> Constraint
return Constraint(ireq.specifier, ireq.hashes(trust_internet=False))
def __nonzero__(self):
# type: () -> bool
return bool(self.specifier) or bool(self.hashes)
def __bool__(self):
# type: () -> bool
return self.__nonzero__()
def __and__(self, other):
# type: (InstallRequirement) -> Constraint
if not isinstance(other, InstallRequirement):
return NotImplemented
specifier = self.specifier & other.specifier
hashes = self.hashes & other.hashes(trust_internet=False)
return Constraint(specifier, hashes)
class Requirement(object):
@property
def name(self):
# type: () -> str
raise NotImplementedError("Subclass should override")
def is_satisfied_by(self, candidate):
# type: (Candidate) -> bool
return False
def get_candidate_lookup(self):
# type: () -> CandidateLookup
raise NotImplementedError("Subclass should override")
def format_for_error(self):
# type: () -> str
raise NotImplementedError("Subclass should override")
class Candidate(object):
@property
def name(self):
# type: () -> str
raise NotImplementedError("Override in subclass")
@property
def version(self):
# type: () -> _BaseVersion
raise NotImplementedError("Override in subclass")
@property
def is_installed(self):
# type: () -> bool
raise NotImplementedError("Override in subclass")
@property
def is_editable(self):
# type: () -> bool
raise NotImplementedError("Override in subclass")
@property
def source_link(self):
# type: () -> Optional[Link]
raise NotImplementedError("Override in subclass")
def iter_dependencies(self, with_requires):
# type: (bool) -> Iterable[Optional[Requirement]]
raise NotImplementedError("Override in subclass")
def get_install_requirement(self):
# type: () -> Optional[InstallRequirement]
raise NotImplementedError("Override in subclass")
def format_for_error(self):
# type: () -> str
raise NotImplementedError("Subclass should override")
|