diff options
Diffstat (limited to 'bsfs/schema/serialize.py')
| -rw-r--r-- | bsfs/schema/serialize.py | 83 |
1 files changed, 46 insertions, 37 deletions
diff --git a/bsfs/schema/serialize.py b/bsfs/schema/serialize.py index a566d65..8b31737 100644 --- a/bsfs/schema/serialize.py +++ b/bsfs/schema/serialize.py @@ -35,13 +35,27 @@ def from_string(schema_str: str) -> schema.Schema: graph.parse(data=schema_str, format='turtle') # helper functions + # FIXME: type annotation + def _fetch_value(subject: URI, predicate: rdflib.URIRef, value_factory) -> typing.Optional[typing.Any]: + """Fetch the object of a given subject and predicate. + Raises a `errors.ConsistencyError` if multiple objects match. + """ + values = list(graph.objects(rdflib.URIRef(subject), predicate)) + if len(values) == 0: + return None + if len(values) == 1: + return value_factory(values[0]) + raise errors.ConsistencyError( + f'{subject} has multiple values for predicate {str(predicate)}, expected zero or one') + def _convert(value): """Convert the subject type from rdflib to a bsfs native type.""" if isinstance(value, rdflib.Literal): return value.value if isinstance(value, rdflib.URIRef): return URI(value) - raise errors.UnreachableError(f'expected Literal or URIRef, found {typename(value)}') + # value is neither a node nor a literal, but e.g. a blank node + raise errors.BackendError(f'expected Literal or URIRef, found {typename(value)}') def _fetch_hierarchically(factory, curr): """Walk through a rdfs:subClassOf hierarchy, creating symbols along the way.""" @@ -71,30 +85,36 @@ def from_string(schema_str: str) -> schema.Schema: raise errors.ConsistencyError('inconsistent nodes') # fetch literals - literals = set(_fetch_hierarchically(types.Literal, types.ROOT_LITERAL)) + def _build_literal(uri, parent, **annotations): + """Literal factory.""" + # break out on root feature type + if uri == types.ROOT_FEATURE.uri: + return types.ROOT_FEATURE + # handle feature types + if isinstance(parent, types.Feature): + # clean annotations + annotations.pop(ns.bsfs.dimension, None) + annotations.pop(ns.bsfs.dtype, None) + annotations.pop(ns.bsfs.distance, None) + # get dimension + dimension = _fetch_value(uri, rdflib.URIRef(ns.bsfs.dimension), int) + # get dtype + dtype = _fetch_value(uri, rdflib.URIRef(ns.bsfs.dtype), URI) + # get distance + distance = _fetch_value(uri, rdflib.URIRef(ns.bsfs.distance), URI) + # return feature + return parent.child(URI(uri), dtype=dtype, dimension=dimension, distance=distance, **annotations) + # handle non-feature types + return parent.child(URI(uri), **annotations) + + literals = set(_fetch_hierarchically(_build_literal, types.ROOT_LITERAL)) literals_lut = {lit.uri: lit for lit in literals} if len(literals_lut) != len(literals): raise errors.ConsistencyError('inconsistent literals') # fetch predicates - # FIXME: type annotation - def _fetch_value(subject: URI, predicate: rdflib.URIRef, value_factory) -> typing.Optional[typing.Any]: - """Fetch the object of a given subject and predicate. - Raises a `errors.ConsistencyError` if multiple objects match. - """ - values = list(graph.objects(rdflib.URIRef(subject), predicate)) - if len(values) == 0: - return None - if len(values) == 1: - return value_factory(values[0]) - raise errors.ConsistencyError( - f'{subject} has multiple values for predicate {str(predicate)}, expected zero or one') - def _build_predicate(uri, parent, **annotations): """Predicate factory.""" - # break out on root feature type - if uri == types.ROOT_FEATURE.uri: - return types.ROOT_FEATURE # clean annotations annotations.pop(ns.rdfs.domain, None) annotations.pop(ns.rdfs.range, None) @@ -113,23 +133,9 @@ def from_string(schema_str: str) -> schema.Schema: rng = nodes_lut.get(rng, literals_lut.get(rng)) # get unique unique = _fetch_value(uri, rdflib.URIRef(ns.bsfs.unique), bool) - # handle feature types - if isinstance(parent, types.Feature): - # clean annotations - annotations.pop(ns.bsfs.dimension, None) - annotations.pop(ns.bsfs.dtype, None) - annotations.pop(ns.bsfs.distance, None) - # get dimension - dimension = _fetch_value(uri, rdflib.URIRef(ns.bsfs.dimension), int) - # get dtype - dtype = _fetch_value(uri, rdflib.URIRef(ns.bsfs.dtype), URI) - # get distance - distance = _fetch_value(uri, rdflib.URIRef(ns.bsfs.distance), URI) - # return feature - return parent.child(URI(uri), domain=dom, range=rng, unique=unique, - dtype=dtype, dimension=dimension, distance=distance, **annotations) - # handle non-feature predicate + # build predicate return parent.child(URI(uri), domain=dom, range=rng, unique=unique, **annotations) + predicates = _fetch_hierarchically(_build_predicate, types.ROOT_PREDICATE) return schema.Schema(predicates, nodes, literals) @@ -214,9 +220,12 @@ def to_string(schema_inst: schema.Schema, fmt: str = 'turtle') -> str: def _parse(node: types._Type) -> T_TRIPLE: """Emit all properties of a type.""" - if isinstance(node, types._Type): # pylint: disable=protected-access - # NOTE: all nodes are _Type - yield from _type(node) + # check arg + if not isinstance(node, types._Type): # pylint: disable=protected-access + raise TypeError(node) + # emit _Type essentials + yield from _type(node) + # emit properties of derived types if isinstance(node, types.Predicate): yield from _predicate(node) if isinstance(node, types.Feature): |