--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/planemo/lib/python3.7/site-packages/rdflib_jsonld/serializer.py	Fri Jul 31 00:32:28 2020 -0400
@@ -0,0 +1,359 @@
+# -*- coding: utf-8 -*-
+"""
+This serialiser will output an RDF Graph as a JSON-LD formatted document. See:
+
+    http://json-ld.org/
+
+Example usage::
+
+    >>> from rdflib.plugin import register, Serializer
+    >>> register('json-ld', Serializer, 'rdflib_jsonld.serializer', 'JsonLDSerializer')
+
+    >>> from rdflib import Graph
+
+    >>> testrdf = '''
+    ... @prefix dc: <http://purl.org/dc/terms/> .
+    ... <http://example.org/about>
+    ...     dc:title "Someone's Homepage"@en .
+    ... '''
+
+    >>> g = Graph().parse(data=testrdf, format='n3')
+
+    >>> print((g.serialize(format='json-ld', indent=4).decode()))
+    [
+        {
+            "@id": "http://example.org/about",
+            "http://purl.org/dc/terms/title": [
+                {
+                    "@language": "en",
+                    "@value": "Someone's Homepage"
+                }
+            ]
+        }
+    ]
+
+"""
+
+# NOTE: This code writes the entire JSON object into memory before serialising,
+# but we should consider streaming the output to deal with arbitrarily large
+# graphs.
+
+import warnings
+
+from rdflib.serializer import Serializer
+from rdflib.graph import Graph
+from rdflib.term import URIRef, Literal, BNode
+from rdflib.namespace import RDF, XSD
+
+from .context import Context, UNDEF
+from .util import json
+from .keys import CONTEXT, GRAPH, ID, VOCAB, LIST, SET, LANG
+
+__all__ = ['JsonLDSerializer', 'from_rdf']
+
+
+PLAIN_LITERAL_TYPES = set([XSD.boolean, XSD.integer, XSD.double, XSD.string])
+
+
+class JsonLDSerializer(Serializer):
+    def __init__(self, store):
+        super(JsonLDSerializer, self).__init__(store)
+
+    def serialize(self, stream, base=None, encoding=None, **kwargs):
+        # TODO: docstring w. args and return value
+        encoding = encoding or 'utf-8'
+        if encoding not in ('utf-8', 'utf-16'):
+            warnings.warn("JSON should be encoded as unicode. " +
+                          "Given encoding was: %s" % encoding)
+
+        context_data = kwargs.get('context')
+        use_native_types = kwargs.get('use_native_types', False),
+        use_rdf_type = kwargs.get('use_rdf_type', False)
+        auto_compact = kwargs.get('auto_compact', False)
+
+        indent = kwargs.get('indent', 2)
+        separators = kwargs.get('separators', (',', ': '))
+        sort_keys = kwargs.get('sort_keys', True)
+        ensure_ascii = kwargs.get('ensure_ascii', False)
+
+        obj = from_rdf(self.store, context_data, base,
+                use_native_types, use_rdf_type,
+                auto_compact=auto_compact)
+
+        data = json.dumps(obj, indent=indent, separators=separators,
+                          sort_keys=sort_keys, ensure_ascii=ensure_ascii)
+
+        stream.write(data.encode(encoding, 'replace'))
+
+
+def from_rdf(graph, context_data=None, base=None,
+        use_native_types=False, use_rdf_type=False,
+        auto_compact=False, startnode=None, index=False):
+    # TODO: docstring w. args and return value
+    # TODO: support for index and startnode
+
+    if not context_data and auto_compact:
+        context_data = dict(
+            (pfx, str(ns))
+            for (pfx, ns) in graph.namespaces() if pfx and
+            str(ns) != "http://www.w3.org/XML/1998/namespace")
+
+    if isinstance(context_data, Context):
+        context = context_data
+        context_data = context.to_dict()
+    else:
+        context = Context(context_data, base=base)
+
+    converter = Converter(context, use_native_types, use_rdf_type)
+    result = converter.convert(graph)
+
+    if converter.context.active:
+        if isinstance(result, list):
+            result = {context.get_key(GRAPH): result}
+        result[CONTEXT] = context_data
+
+    return result
+
+
+class Converter(object):
+
+    def __init__(self, context, use_native_types, use_rdf_type):
+        self.context = context
+        self.use_native_types = context.active or use_native_types
+        self.use_rdf_type = use_rdf_type
+
+    def convert(self, graph):
+        # TODO: bug in rdflib dataset parsing (nquads et al):
+        # plain triples end up in separate unnamed graphs (rdflib issue #436)
+        if graph.context_aware:
+            default_graph = Graph()
+            graphs = [default_graph]
+            for g in graph.contexts():
+                if isinstance(g.identifier, URIRef):
+                    graphs.append(g)
+                else:
+                    default_graph += g
+        else:
+            graphs = [graph]
+
+        context = self.context
+
+        objs = []
+        for g in graphs:
+            obj = {}
+            graphname = None
+
+            if isinstance(g.identifier, URIRef):
+                graphname = context.shrink_iri(g.identifier)
+                obj[context.id_key] = graphname
+
+            nodes = self.from_graph(g)
+
+            if not graphname and len(nodes) == 1:
+                obj.update(nodes[0])
+            else:
+                if not nodes:
+                    continue
+                obj[context.graph_key] = nodes
+
+            if objs and objs[0].get(context.get_key(ID)) == graphname:
+                objs[0].update(obj)
+            else:
+                objs.append(obj)
+
+        if len(graphs) == 1 and len(objs) == 1 and not self.context.active:
+            default = objs[0]
+            items = default.get(context.graph_key)
+            if len(default) == 1 and items:
+                objs = items
+        elif len(objs) == 1 and self.context.active:
+            objs = objs[0]
+
+        return objs
+
+    def from_graph(self, graph):
+        nodemap = {}
+
+        for s in set(graph.subjects()):
+            ## only iri:s and unreferenced (rest will be promoted to top if needed)
+            if isinstance(s, URIRef) or (isinstance(s, BNode)
+                    and not any(graph.subjects(None, s))):
+                self.process_subject(graph, s, nodemap)
+
+        return list(nodemap.values())
+
+    def process_subject(self, graph, s, nodemap):
+        if isinstance(s, URIRef):
+            node_id = self.context.shrink_iri(s)
+        elif isinstance(s, BNode):
+            node_id = s.n3()
+        else:
+            node_id = None
+
+        #used_as_object = any(graph.subjects(None, s))
+        if node_id in nodemap:
+            return None
+
+        node = {}
+        node[self.context.id_key] = node_id
+        nodemap[node_id] = node
+
+        for p, o in graph.predicate_objects(s):
+            self.add_to_node(graph, s, p, o, node, nodemap)
+
+        return node
+
+    def add_to_node(self, graph, s, p, o, s_node, nodemap):
+        context = self.context
+
+        if isinstance(o, Literal):
+            datatype = str(o.datatype) if o.datatype else None
+            language = o.language
+            term = context.find_term(str(p), datatype, language=language)
+        else:
+            containers = [LIST, None] if graph.value(o, RDF.first) else [None]
+            for container in containers:
+                for coercion in (ID, VOCAB, UNDEF):
+                    term = context.find_term(str(p), coercion, container)
+                    if term:
+                        break
+                if term:
+                    break
+
+        node = None
+        use_set = not context.active
+
+        if term:
+            p_key = term.name
+
+            if term.type:
+                node = self.type_coerce(o, term.type)
+            elif term.language and o.language == term.language:
+                node = str(o)
+            elif context.language and (
+                    term.language is None and o.language is None):
+                node = str(o)
+
+            if term.container == SET:
+                use_set = True
+            elif term.container == LIST:
+                node = [self.type_coerce(v, term.type) or self.to_raw_value(graph, s, v, nodemap)
+                        for v in self.to_collection(graph, o)]
+            elif term.container == LANG and language:
+                value = s_node.setdefault(p_key, {})
+                values = value.get(language)
+                node = str(o)
+                if values:
+                    if not isinstance(values, list):
+                        value[language] = values = [values]
+                    values.append(node)
+                else:
+                    value[language] = node
+                return
+
+        else:
+            p_key = context.to_symbol(p)
+            # TODO: for coercing curies - quite clumsy; unify to_symbol and find_term?
+            key_term = context.terms.get(p_key)
+            if key_term and (key_term.type or key_term.container):
+                p_key = p
+            if not term and p == RDF.type and not self.use_rdf_type:
+                if isinstance(o, URIRef):
+                    node = context.to_symbol(o)
+                p_key = context.type_key
+
+        if node is None:
+            node = self.to_raw_value(graph, s, o, nodemap)
+
+        value = s_node.get(p_key)
+        if value:
+            if not isinstance(value, list):
+                value = [value]
+            value.append(node)
+        elif use_set:
+            value = [node]
+        else:
+            value = node
+        s_node[p_key] = value
+
+    def type_coerce(self, o, coerce_type):
+        if coerce_type == ID:
+            if isinstance(o, URIRef):
+                return self.context.shrink_iri(o)
+            elif isinstance(o, BNode):
+                return o.n3()
+            else:
+                return o
+        elif coerce_type == VOCAB and isinstance(o, URIRef):
+            return self.context.to_symbol(o)
+        elif isinstance(o, Literal) and str(o.datatype) == coerce_type:
+            return o
+        else:
+            return None
+
+    def to_raw_value(self, graph, s, o, nodemap):
+        context = self.context
+        coll = self.to_collection(graph, o)
+        if coll is not None:
+            coll = [self.to_raw_value(graph, s, lo, nodemap)
+                    for lo in self.to_collection(graph, o)]
+            return {context.list_key: coll}
+        elif isinstance(o, BNode):
+            embed = False # TODO: self.context.active or using startnode and only one ref
+            onode = self.process_subject(graph, o, nodemap)
+            if onode:
+                if embed and not any(s2 for s2 in graph.subjects(None, o) if s2 != s):
+                    return onode
+                else:
+                    nodemap[onode[context.id_key]] = onode
+            return {context.id_key: o.n3()}
+        elif isinstance(o, URIRef):
+            # TODO: embed if o != startnode (else reverse)
+            return {context.id_key: context.shrink_iri(o)}
+        elif isinstance(o, Literal):
+            # TODO: if compact
+            native = self.use_native_types and o.datatype in PLAIN_LITERAL_TYPES
+            if native:
+                v = o.toPython()
+            else:
+                v = str(o)
+            if o.datatype:
+                if native:
+                    if self.context.active:
+                        return v
+                    else:
+                        return {context.value_key: v}
+                return {context.type_key: context.to_symbol(o.datatype),
+                        context.value_key: v}
+            elif o.language and o.language != context.language:
+                return {context.lang_key: o.language,
+                        context.value_key: v}
+            elif not context.active or context.language and not o.language:
+                return {context.value_key: v}
+            else:
+                return v
+
+    def to_collection(self, graph, l):
+        if l != RDF.nil and not graph.value(l, RDF.first):
+            return None
+        list_nodes = []
+        chain = set([l])
+        while l:
+            if l == RDF.nil:
+                return list_nodes
+            if isinstance(l, URIRef):
+                return None
+            first, rest = None, None
+            for p, o in graph.predicate_objects(l):
+                if not first and p == RDF.first:
+                    first = o
+                elif not rest and p == RDF.rest:
+                    rest = o
+                elif p != RDF.type or o != RDF.List:
+                    return None
+            list_nodes.append(first)
+            l = rest
+            if l in chain:
+                return None
+            chain.add(l)
+