228 lines
8.8 KiB
Python
228 lines
8.8 KiB
Python
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__all__ = ['BaseResolver', 'Resolver']
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from .error import *
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from .nodes import *
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import re
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class ResolverError(YAMLError):
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pass
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class BaseResolver:
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DEFAULT_SCALAR_TAG = 'tag:yaml.org,2002:str'
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DEFAULT_SEQUENCE_TAG = 'tag:yaml.org,2002:seq'
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DEFAULT_MAPPING_TAG = 'tag:yaml.org,2002:map'
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yaml_implicit_resolvers = {}
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yaml_path_resolvers = {}
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def __init__(self):
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self.resolver_exact_paths = []
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self.resolver_prefix_paths = []
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@classmethod
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def add_implicit_resolver(cls, tag, regexp, first):
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if not 'yaml_implicit_resolvers' in cls.__dict__:
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implicit_resolvers = {}
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for key in cls.yaml_implicit_resolvers:
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implicit_resolvers[key] = cls.yaml_implicit_resolvers[key][:]
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cls.yaml_implicit_resolvers = implicit_resolvers
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if first is None:
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first = [None]
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for ch in first:
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cls.yaml_implicit_resolvers.setdefault(ch, []).append((tag, regexp))
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@classmethod
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def add_path_resolver(cls, tag, path, kind=None):
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# Note: `add_path_resolver` is experimental. The API could be changed.
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# `new_path` is a pattern that is matched against the path from the
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# root to the node that is being considered. `node_path` elements are
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# tuples `(node_check, index_check)`. `node_check` is a node class:
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# `ScalarNode`, `SequenceNode`, `MappingNode` or `None`. `None`
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# matches any kind of a node. `index_check` could be `None`, a boolean
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# value, a string value, or a number. `None` and `False` match against
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# any _value_ of sequence and mapping nodes. `True` matches against
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# any _key_ of a mapping node. A string `index_check` matches against
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# a mapping value that corresponds to a scalar key which content is
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# equal to the `index_check` value. An integer `index_check` matches
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# against a sequence value with the index equal to `index_check`.
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if not 'yaml_path_resolvers' in cls.__dict__:
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cls.yaml_path_resolvers = cls.yaml_path_resolvers.copy()
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new_path = []
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for element in path:
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if isinstance(element, (list, tuple)):
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if len(element) == 2:
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node_check, index_check = element
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elif len(element) == 1:
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node_check = element[0]
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index_check = True
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else:
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raise ResolverError("Invalid path element: %s" % element)
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else:
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node_check = None
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index_check = element
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if node_check is str:
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node_check = ScalarNode
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elif node_check is list:
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node_check = SequenceNode
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elif node_check is dict:
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node_check = MappingNode
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elif node_check not in [ScalarNode, SequenceNode, MappingNode] \
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and not isinstance(node_check, str) \
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and node_check is not None:
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raise ResolverError("Invalid node checker: %s" % node_check)
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if not isinstance(index_check, (str, int)) \
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and index_check is not None:
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raise ResolverError("Invalid index checker: %s" % index_check)
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new_path.append((node_check, index_check))
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if kind is str:
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kind = ScalarNode
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elif kind is list:
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kind = SequenceNode
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elif kind is dict:
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kind = MappingNode
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elif kind not in [ScalarNode, SequenceNode, MappingNode] \
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and kind is not None:
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raise ResolverError("Invalid node kind: %s" % kind)
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cls.yaml_path_resolvers[tuple(new_path), kind] = tag
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def descend_resolver(self, current_node, current_index):
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if not self.yaml_path_resolvers:
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return
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exact_paths = {}
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prefix_paths = []
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if current_node:
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depth = len(self.resolver_prefix_paths)
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for path, kind in self.resolver_prefix_paths[-1]:
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if self.check_resolver_prefix(depth, path, kind,
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current_node, current_index):
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if len(path) > depth:
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prefix_paths.append((path, kind))
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else:
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exact_paths[kind] = self.yaml_path_resolvers[path, kind]
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else:
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for path, kind in self.yaml_path_resolvers:
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if not path:
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exact_paths[kind] = self.yaml_path_resolvers[path, kind]
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else:
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prefix_paths.append((path, kind))
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self.resolver_exact_paths.append(exact_paths)
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self.resolver_prefix_paths.append(prefix_paths)
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def ascend_resolver(self):
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if not self.yaml_path_resolvers:
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return
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self.resolver_exact_paths.pop()
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self.resolver_prefix_paths.pop()
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def check_resolver_prefix(self, depth, path, kind,
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current_node, current_index):
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node_check, index_check = path[depth-1]
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if isinstance(node_check, str):
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if current_node.tag != node_check:
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return
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elif node_check is not None:
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if not isinstance(current_node, node_check):
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return
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if index_check is True and current_index is not None:
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return
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if (index_check is False or index_check is None) \
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and current_index is None:
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return
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if isinstance(index_check, str):
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if not (isinstance(current_index, ScalarNode)
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and index_check == current_index.value):
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return
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elif isinstance(index_check, int) and not isinstance(index_check, bool):
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if index_check != current_index:
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return
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return True
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def resolve(self, kind, value, implicit):
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if kind is ScalarNode and implicit[0]:
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if value == '':
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resolvers = self.yaml_implicit_resolvers.get('', [])
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else:
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resolvers = self.yaml_implicit_resolvers.get(value[0], [])
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resolvers += self.yaml_implicit_resolvers.get(None, [])
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for tag, regexp in resolvers:
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if regexp.match(value):
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return tag
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implicit = implicit[1]
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if self.yaml_path_resolvers:
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exact_paths = self.resolver_exact_paths[-1]
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if kind in exact_paths:
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return exact_paths[kind]
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if None in exact_paths:
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return exact_paths[None]
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if kind is ScalarNode:
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return self.DEFAULT_SCALAR_TAG
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elif kind is SequenceNode:
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return self.DEFAULT_SEQUENCE_TAG
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elif kind is MappingNode:
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return self.DEFAULT_MAPPING_TAG
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class Resolver(BaseResolver):
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pass
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Resolver.add_implicit_resolver(
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'tag:yaml.org,2002:bool',
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re.compile(r'''^(?:yes|Yes|YES|no|No|NO
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|true|True|TRUE|false|False|FALSE
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|on|On|ON|off|Off|OFF)$''', re.X),
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list('yYnNtTfFoO'))
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Resolver.add_implicit_resolver(
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'tag:yaml.org,2002:float',
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re.compile(r'''^(?:[-+]?(?:[0-9][0-9_]*)\.[0-9_]*(?:[eE][-+][0-9]+)?
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|\.[0-9_]+(?:[eE][-+][0-9]+)?
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|[-+]?[0-9][0-9_]*(?::[0-5]?[0-9])+\.[0-9_]*
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|[-+]?\.(?:inf|Inf|INF)
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|\.(?:nan|NaN|NAN))$''', re.X),
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list('-+0123456789.'))
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Resolver.add_implicit_resolver(
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'tag:yaml.org,2002:int',
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re.compile(r'''^(?:[-+]?0b[0-1_]+
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|[-+]?0[0-7_]+
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|[-+]?(?:0|[1-9][0-9_]*)
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|[-+]?0x[0-9a-fA-F_]+
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|[-+]?[1-9][0-9_]*(?::[0-5]?[0-9])+)$''', re.X),
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list('-+0123456789'))
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Resolver.add_implicit_resolver(
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'tag:yaml.org,2002:merge',
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re.compile(r'^(?:<<)$'),
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['<'])
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Resolver.add_implicit_resolver(
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'tag:yaml.org,2002:null',
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re.compile(r'''^(?: ~
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|null|Null|NULL
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['~', 'n', 'N', ''])
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Resolver.add_implicit_resolver(
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'tag:yaml.org,2002:timestamp',
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re.compile(r'''^(?:[0-9][0-9][0-9][0-9]-[0-9][0-9]-[0-9][0-9]
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|[0-9][0-9][0-9][0-9] -[0-9][0-9]? -[0-9][0-9]?
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(?:[Tt]|[ \t]+)[0-9][0-9]?
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:[0-9][0-9] :[0-9][0-9] (?:\.[0-9]*)?
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(?:[ \t]*(?:Z|[-+][0-9][0-9]?(?::[0-9][0-9])?))?)$''', re.X),
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list('0123456789'))
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Resolver.add_implicit_resolver(
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'tag:yaml.org,2002:value',
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re.compile(r'^(?:=)$'),
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['='])
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# The following resolver is only for documentation purposes. It cannot work
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# because plain scalars cannot start with '!', '&', or '*'.
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Resolver.add_implicit_resolver(
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'tag:yaml.org,2002:yaml',
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re.compile(r'^(?:!|&|\*)$'),
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list('!&*'))
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