302 lines
8.0 KiB
Python
302 lines
8.0 KiB
Python
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# This file is dual licensed under the terms of the Apache License, Version
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# 2.0, and the BSD License. See the LICENSE file in the root of this repository
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# for complete details.
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from __future__ import absolute_import, division, print_function
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import operator
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import os
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import platform
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import sys
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from pyparsing import ParseException, ParseResults, stringStart, stringEnd
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from pyparsing import ZeroOrMore, Group, Forward, QuotedString
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from pyparsing import Literal as L # noqa
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from ._compat import string_types
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from .specifiers import Specifier, InvalidSpecifier
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__all__ = [
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"InvalidMarker", "UndefinedComparison", "UndefinedEnvironmentName",
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"Marker", "default_environment",
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]
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class InvalidMarker(ValueError):
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"""
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An invalid marker was found, users should refer to PEP 508.
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"""
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class UndefinedComparison(ValueError):
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"""
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An invalid operation was attempted on a value that doesn't support it.
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"""
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class UndefinedEnvironmentName(ValueError):
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"""
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A name was attempted to be used that does not exist inside of the
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environment.
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"""
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class Node(object):
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def __init__(self, value):
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self.value = value
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def __str__(self):
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return str(self.value)
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def __repr__(self):
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return "<{0}({1!r})>".format(self.__class__.__name__, str(self))
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def serialize(self):
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raise NotImplementedError
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class Variable(Node):
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def serialize(self):
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return str(self)
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class Value(Node):
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def serialize(self):
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return '"{0}"'.format(self)
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class Op(Node):
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def serialize(self):
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return str(self)
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VARIABLE = (
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L("implementation_version") |
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L("platform_python_implementation") |
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L("implementation_name") |
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L("python_full_version") |
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L("platform_release") |
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L("platform_version") |
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L("platform_machine") |
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L("platform_system") |
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L("python_version") |
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L("sys_platform") |
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L("os_name") |
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L("os.name") | # PEP-345
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L("sys.platform") | # PEP-345
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L("platform.version") | # PEP-345
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L("platform.machine") | # PEP-345
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L("platform.python_implementation") | # PEP-345
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L("python_implementation") | # undocumented setuptools legacy
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L("extra")
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)
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ALIASES = {
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'os.name': 'os_name',
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'sys.platform': 'sys_platform',
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'platform.version': 'platform_version',
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'platform.machine': 'platform_machine',
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'platform.python_implementation': 'platform_python_implementation',
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'python_implementation': 'platform_python_implementation'
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}
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VARIABLE.setParseAction(lambda s, l, t: Variable(ALIASES.get(t[0], t[0])))
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VERSION_CMP = (
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L("===") |
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L("==") |
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L(">=") |
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L("<=") |
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L("!=") |
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L("~=") |
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L(">") |
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L("<")
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)
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MARKER_OP = VERSION_CMP | L("not in") | L("in")
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MARKER_OP.setParseAction(lambda s, l, t: Op(t[0]))
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MARKER_VALUE = QuotedString("'") | QuotedString('"')
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MARKER_VALUE.setParseAction(lambda s, l, t: Value(t[0]))
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BOOLOP = L("and") | L("or")
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MARKER_VAR = VARIABLE | MARKER_VALUE
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MARKER_ITEM = Group(MARKER_VAR + MARKER_OP + MARKER_VAR)
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MARKER_ITEM.setParseAction(lambda s, l, t: tuple(t[0]))
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LPAREN = L("(").suppress()
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RPAREN = L(")").suppress()
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MARKER_EXPR = Forward()
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MARKER_ATOM = MARKER_ITEM | Group(LPAREN + MARKER_EXPR + RPAREN)
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MARKER_EXPR << MARKER_ATOM + ZeroOrMore(BOOLOP + MARKER_EXPR)
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MARKER = stringStart + MARKER_EXPR + stringEnd
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def _coerce_parse_result(results):
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if isinstance(results, ParseResults):
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return [_coerce_parse_result(i) for i in results]
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else:
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return results
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def _format_marker(marker, first=True):
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assert isinstance(marker, (list, tuple, string_types))
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# Sometimes we have a structure like [[...]] which is a single item list
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# where the single item is itself it's own list. In that case we want skip
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# the rest of this function so that we don't get extraneous () on the
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# outside.
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if (isinstance(marker, list) and len(marker) == 1 and
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isinstance(marker[0], (list, tuple))):
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return _format_marker(marker[0])
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if isinstance(marker, list):
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inner = (_format_marker(m, first=False) for m in marker)
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if first:
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return " ".join(inner)
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else:
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return "(" + " ".join(inner) + ")"
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elif isinstance(marker, tuple):
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return " ".join([m.serialize() for m in marker])
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else:
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return marker
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_operators = {
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"in": lambda lhs, rhs: lhs in rhs,
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"not in": lambda lhs, rhs: lhs not in rhs,
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"<": operator.lt,
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"<=": operator.le,
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"==": operator.eq,
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"!=": operator.ne,
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">=": operator.ge,
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">": operator.gt,
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}
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def _eval_op(lhs, op, rhs):
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try:
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spec = Specifier("".join([op.serialize(), rhs]))
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except InvalidSpecifier:
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pass
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else:
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return spec.contains(lhs)
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oper = _operators.get(op.serialize())
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if oper is None:
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raise UndefinedComparison(
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"Undefined {0!r} on {1!r} and {2!r}.".format(op, lhs, rhs)
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)
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return oper(lhs, rhs)
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_undefined = object()
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def _get_env(environment, name):
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value = environment.get(name, _undefined)
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if value is _undefined:
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raise UndefinedEnvironmentName(
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"{0!r} does not exist in evaluation environment.".format(name)
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)
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return value
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def _evaluate_markers(markers, environment):
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groups = [[]]
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for marker in markers:
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assert isinstance(marker, (list, tuple, string_types))
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if isinstance(marker, list):
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groups[-1].append(_evaluate_markers(marker, environment))
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elif isinstance(marker, tuple):
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lhs, op, rhs = marker
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if isinstance(lhs, Variable):
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lhs_value = _get_env(environment, lhs.value)
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rhs_value = rhs.value
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else:
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lhs_value = lhs.value
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rhs_value = _get_env(environment, rhs.value)
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groups[-1].append(_eval_op(lhs_value, op, rhs_value))
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else:
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assert marker in ["and", "or"]
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if marker == "or":
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groups.append([])
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return any(all(item) for item in groups)
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def format_full_version(info):
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version = '{0.major}.{0.minor}.{0.micro}'.format(info)
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kind = info.releaselevel
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if kind != 'final':
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version += kind[0] + str(info.serial)
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return version
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def default_environment():
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if hasattr(sys, 'implementation'):
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iver = format_full_version(sys.implementation.version)
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implementation_name = sys.implementation.name
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else:
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iver = '0'
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implementation_name = ''
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return {
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"implementation_name": implementation_name,
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"implementation_version": iver,
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"os_name": os.name,
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"platform_machine": platform.machine(),
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"platform_release": platform.release(),
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"platform_system": platform.system(),
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"platform_version": platform.version(),
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"python_full_version": platform.python_version(),
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"platform_python_implementation": platform.python_implementation(),
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"python_version": platform.python_version()[:3],
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"sys_platform": sys.platform,
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}
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class Marker(object):
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def __init__(self, marker):
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try:
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self._markers = _coerce_parse_result(MARKER.parseString(marker))
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except ParseException as e:
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err_str = "Invalid marker: {0!r}, parse error at {1!r}".format(
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marker, marker[e.loc:e.loc + 8])
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raise InvalidMarker(err_str)
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def __str__(self):
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return _format_marker(self._markers)
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def __repr__(self):
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return "<Marker({0!r})>".format(str(self))
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def evaluate(self, environment=None):
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"""Evaluate a marker.
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Return the boolean from evaluating the given marker against the
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environment. environment is an optional argument to override all or
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part of the determined environment.
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The environment is determined from the current Python process.
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"""
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current_environment = default_environment()
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if environment is not None:
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current_environment.update(environment)
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return _evaluate_markers(self._markers, current_environment)
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