Edit File: resolver.py
__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('!&*'))