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