refactored naming policy into uri matcher

39 files changed, 591 insertions, 559 deletions

diff --git a/bsie/apps/index.py b/bsie/apps/index.py
index 7dda6f4..260d3c8 100644
--- a/bsie/apps/index.py
+++ b/bsie/apps/index.py
@@ -5,8 +5,9 @@ import os
 import typing
 
 # bsie imports
-from bsie.lib import BSIE, DefaultNamingPolicy
-from bsie.utils import bsfs, errors, node as node_, list_files
+from bsie.lib import BSIE
+from bsie.matcher import nodes, DefaultMatcher
+from bsie.utils import bsfs, errors, list_files
 
 # inner-module imports
 from . import _loader
@@ -45,13 +46,13 @@ def main(argv):
 
     # build pipeline
     pipeline = _loader.load_pipeline(args.config)
-    # build the naming policy
-    naming_policy = DefaultNamingPolicy(
+    # build the node matcher
+    matcher = DefaultMatcher(
         host=args.host,
         user=args.user,
         )
     # build BSIE frontend
-    bsie = BSIE(pipeline, naming_policy, args.collect, args.discard)
+    bsie = BSIE(pipeline, matcher, args.collect, args.discard)
 
     def walk(handle):
         """Walk through given input files."""
diff --git a/bsie/extractor/base.py b/bsie/extractor/base.py
index f92d7cc..bb2ee81 100644
--- a/bsie/extractor/base.py
+++ b/bsie/extractor/base.py
@@ -5,7 +5,8 @@ import abc
 import typing
 
 # bsie imports
-from bsie.utils import bsfs, node, ns
+from bsie.matcher import nodes
+from bsie.utils import bsfs, ns
 
 # exports
 __all__: typing.Sequence[str] = (
@@ -106,10 +107,10 @@ class Extractor(abc.ABC):
     @abc.abstractmethod
     def extract(
             self,
-            subject: node.Node,
+            subject: nodes.Entity,
             content: typing.Any,
             principals: typing.Iterable[bsfs.schema.Predicate],
-            ) -> typing.Iterator[typing.Tuple[node.Node, bsfs.schema.Predicate, typing.Any]]:
+            ) -> typing.Iterator[typing.Tuple[nodes.Node, bsfs.schema.Predicate, typing.Any]]:
         """Return (node, predicate, value) triples."""
         # FIXME: type annotation could be more strict: value is Hashable
 
diff --git a/bsie/extractor/generic/constant.py b/bsie/extractor/generic/constant.py
index 7acbe95..e038c0b 100644
--- a/bsie/extractor/generic/constant.py
+++ b/bsie/extractor/generic/constant.py
@@ -4,7 +4,8 @@
 import typing
 
 # bsie imports
-from bsie.utils import bsfs, node
+from bsie.matcher import nodes
+from bsie.utils import bsfs
 
 # inner-module imports
 from .. import base
@@ -44,10 +45,10 @@ class Constant(base.Extractor):
 
     def extract(
             self,
-            subject: node.Node,
+            subject: nodes.Entity,
             content: None,
             principals: typing.Iterable[bsfs.schema.Predicate],
-            ) -> typing.Iterator[typing.Tuple[node.Node, bsfs.schema.Predicate, typing.Any]]:
+            ) -> typing.Iterator[typing.Tuple[nodes.Node, bsfs.schema.Predicate, typing.Any]]:
         for pred, value in self._tuples:
             if pred in principals:
                 yield subject, pred, value
diff --git a/bsie/extractor/generic/path.py b/bsie/extractor/generic/path.py
index 30d75cf..7fe157b 100644
--- a/bsie/extractor/generic/path.py
+++ b/bsie/extractor/generic/path.py
@@ -5,7 +5,8 @@ import typing
 
 # bsie imports
 from bsie.extractor import base
-from bsie.utils import bsfs, node, ns
+from bsie.matcher import nodes
+from bsie.utils import bsfs, ns
 
 # exports
 __all__: typing.Sequence[str] = (
@@ -41,14 +42,15 @@ class Path(base.Extractor):
             '''))
         self._callmap = {
             self.schema.predicate(ns.bse.filename): self.__filename,
+            self.schema.predicate(ns.bse.dirname): self.__dirname,
             }
 
     def extract(
             self,
-            subject: node.Node,
+            subject: nodes.Entity,
             content: str,
             principals: typing.Iterable[bsfs.schema.Predicate],
-            ) -> typing.Iterator[typing.Tuple[node.Node, bsfs.schema.Predicate, typing.Any]]:
+            ) -> typing.Iterator[typing.Tuple[nodes.Node, bsfs.schema.Predicate, typing.Any]]:
         for pred in principals:
             # find callback
             clbk = self._callmap.get(pred)
diff --git a/bsie/extractor/generic/stat.py b/bsie/extractor/generic/stat.py
index 92b51f3..ff51cff 100644
--- a/bsie/extractor/generic/stat.py
+++ b/bsie/extractor/generic/stat.py
@@ -5,7 +5,8 @@ import os
 import typing
 
 # bsie imports
-from bsie.utils import bsfs, node, ns
+from bsie.matcher import nodes
+from bsie.utils import bsfs, ns
 
 # inner-module imports
 from .. import base
@@ -41,10 +42,10 @@ class Stat(base.Extractor):
 
     def extract(
             self,
-            subject: node.Node,
+            subject: nodes.Entity,
             content: os.stat_result,
             principals: typing.Iterable[bsfs.schema.Predicate],
-            ) -> typing.Iterator[typing.Tuple[node.Node, bsfs.schema.Predicate, typing.Any]]:
+            ) -> typing.Iterator[typing.Tuple[nodes.Node, bsfs.schema.Predicate, typing.Any]]:
         for pred in principals:
             # find callback
             clbk = self._callmap.get(pred)
diff --git a/bsie/extractor/image/colors_spatial.py b/bsie/extractor/image/colors_spatial.py
index e6661a9..bccefc1 100644
--- a/bsie/extractor/image/colors_spatial.py
+++ b/bsie/extractor/image/colors_spatial.py
@@ -8,7 +8,8 @@ import PIL.Image
 import numpy as np
 
 # bsie imports
-from bsie.utils import bsfs, node, ns
+from bsie.matcher import nodes
+from bsie.utils import bsfs, ns
 
 # inner-module imports
 from .. import base
@@ -115,10 +116,10 @@ class ColorsSpatial(base.Extractor):
 
     def extract(
             self,
-            subject: node.Node,
+            subject: nodes.Entity,
             content: PIL.Image.Image,
             principals: typing.Iterable[bsfs.schema.Predicate],
-            ) -> typing.Iterator[typing.Tuple[node.Node, bsfs.schema.Predicate, typing.Any]]:
+            ) -> typing.Iterator[typing.Tuple[nodes.Node, bsfs.schema.Predicate, typing.Any]]:
         # check principals
         if self.schema.predicate(self._predicate_name) not in principals:
             # nothing to do; abort
diff --git a/bsie/extractor/image/face/detect.py b/bsie/extractor/image/face/detect.py
index 94e3a61..51d5659 100644
--- a/bsie/extractor/image/face/detect.py
+++ b/bsie/extractor/image/face/detect.py
@@ -7,7 +7,8 @@ import torch
 from facenet_pytorch import MTCNN, InceptionResnetV1
 
 # bsie imports
-from bsie.utils import bsfs, node, ns
+from bsie.matcher import nodes
+from bsie.utils import bsfs, ns
 
 # inner-module imports
 from ... import base
@@ -72,17 +73,17 @@ class FaceDetect(base.Extractor):
 
     def extract(
             self,
-            subject: node.Node,
+            subject: nodes.Entity,
             content: dict,
             principals: typing.Iterable[bsfs.schema.Predicate],
-            ) -> typing.Iterator[typing.Tuple[node.Node, bsfs.schema.Predicate, typing.Any]]:
+            ) -> typing.Iterator[typing.Tuple[nodes.Node, bsfs.schema.Predicate, typing.Any]]:
         # check principals
         if self.schema.predicate(ns.bse.face) not in principals:
             # nothing to do; abort
             return
 
         for face in content:
-            fnode = node.Node(ns.bsn.Face, ucid=face['ucid'])
+            fnode = nodes.Face(ucid=face['ucid'])
             yield subject, ns.bse.face, fnode
             yield fnode, bsf.x, face['x']
             yield fnode, bsf.y, face['y']
diff --git a/bsie/extractor/image/face/identify.py b/bsie/extractor/image/face/identify.py
index 152f113..44a75c4 100644
--- a/bsie/extractor/image/face/identify.py
+++ b/bsie/extractor/image/face/identify.py
@@ -9,7 +9,8 @@ import numpy as np
 import torch
 
 # bsie imports
-from bsie.utils import bsfs, node, ns
+from bsie.matcher import nodes
+from bsie.utils import bsfs, ns
 
 # inner-module imports
 from ... import base
@@ -142,10 +143,10 @@ class FaceIdentify(base.Extractor):
 
     def extract(
             self,
-            subject: node.Node,
+            subject: nodes.Entity,
             content: typing.Any,
             principals: typing.Iterable[bsfs.schema.Predicate],
-            ) -> typing.Iterator[typing.Tuple[node.Node, bsfs.schema.Predicate, typing.Any]]:
+            ) -> typing.Iterator[typing.Tuple[nodes.Node, bsfs.schema.Predicate, typing.Any]]:
         # check principals
         #if self.schema.predicate(bsf.depicts) not in principals:
         if self.schema.predicate(ns.bse.face) not in principals:
@@ -164,8 +165,8 @@ class FaceIdentify(base.Extractor):
             lbl = bsfs.URI(self._id2name[idx]) # label (uri) of nearest neighbour
             if lbl == self._restklasse: # suppress
                 continue
-            pnode = node.Node(ns.bsn.Person, uri=lbl)
-            fnode = node.Node(ns.bsn.Face, ucid=face['ucid'])
+            pnode = nodes.Person(uri=lbl)
+            fnode = nodes.Face(ucid=face['ucid'])
             # emit triple
             yield fnode, self.schema.predicate(bsf.depicts), pnode
             # FIXME: emit subject -> face -> fnode?
diff --git a/bsie/extractor/image/iptc.py b/bsie/extractor/image/iptc.py
index 195eff7..0c03539 100644
--- a/bsie/extractor/image/iptc.py
+++ b/bsie/extractor/image/iptc.py
@@ -3,7 +3,8 @@
 import typing
 
 # bsie imports
-from bsie.utils import bsfs, node, ns
+from bsie.matcher import nodes
+from bsie.utils import bsfs, ns
 
 # inner-module imports
 from .. import base
@@ -41,10 +42,10 @@ class Iptc(base.Extractor):
 
     def extract(
             self,
-            subject: node.Node,
+            subject: nodes.Entity,
             content: dict,
             principals: typing.Iterable[bsfs.schema.Predicate],
-            ) -> typing.Iterator[typing.Tuple[node.Node, bsfs.schema.Predicate, typing.Any]]:
+            ) -> typing.Iterator[typing.Tuple[nodes.Node, bsfs.schema.Predicate, typing.Any]]:
         for pred in principals:
             # find callback
             clbk = self._callmap.get(pred)
@@ -55,13 +56,13 @@ class Iptc(base.Extractor):
 
     def _keywords(
             self,
-            subject: node.Node,
+            subject: nodes.Entity,
             content: dict,
-            ) -> typing.Iterator[typing.Tuple[node.Node, bsfs.schema.Predicate, typing.Any]]:
+            ) -> typing.Iterator[typing.Tuple[nodes.Node, bsfs.schema.Predicate, typing.Any]]:
         if 'Iptc.Application2.Keywords' not in content:
             return
         for keyword in content['Iptc.Application2.Keywords']:
-            tag = node.Node(ns.bsn.Tag, label=keyword)
+            tag = nodes.Tag(label=keyword)
             yield subject, self.schema.predicate(ns.bse.tag), tag
             yield tag, self.schema.predicate(ns.bst.label), keyword
 
diff --git a/bsie/extractor/image/photometrics.py b/bsie/extractor/image/photometrics.py
index 42eb3c8..4579b54 100644
--- a/bsie/extractor/image/photometrics.py
+++ b/bsie/extractor/image/photometrics.py
@@ -4,7 +4,8 @@ from fractions import Fraction
 import typing
 
 # bsie imports
-from bsie.utils import bsfs, node, ns
+from bsie.matcher import nodes
+from bsie.utils import bsfs, ns
 
 # inner-module imports
 from .. import base
@@ -107,10 +108,10 @@ class Exif(base.Extractor):
 
     def extract(
             self,
-            subject: node.Node,
+            subject: nodes.Entity,
             content: dict,
             principals: typing.Iterable[bsfs.schema.Predicate],
-            ) -> typing.Iterator[typing.Tuple[node.Node, bsfs.schema.Predicate, typing.Any]]:
+            ) -> typing.Iterator[typing.Tuple[nodes.Node, bsfs.schema.Predicate, typing.Any]]:
         for pred in principals:
             # find callback
             clbk = self._callmap.get(pred)
diff --git a/bsie/extractor/preview.py b/bsie/extractor/preview.py
index 145a01a..fcda71c 100644
--- a/bsie/extractor/preview.py
+++ b/bsie/extractor/preview.py
@@ -7,7 +7,8 @@ import typing
 import PIL.Image
 
 # bsie imports
-from bsie.utils import bsfs, node, ns
+from bsie.matcher import nodes
+from bsie.utils import bsfs, ns
 
 # inner-module imports
 from . import base
@@ -67,10 +68,10 @@ class Preview(base.Extractor):
 
     def extract(
             self,
-            subject: node.Node,
+            subject: nodes.Entity,
             content: typing.Callable[[int], PIL.Image.Image],
             principals: typing.Iterable[bsfs.schema.Predicate],
-            ) -> typing.Iterator[typing.Tuple[node.Node, bsfs.schema.Predicate, typing.Any]]:
+            ) -> typing.Iterator[typing.Tuple[nodes.Node, bsfs.schema.Predicate, typing.Any]]:
         # check principals
         if self.schema.predicate(ns.bse.preview) not in principals:
             return
@@ -82,10 +83,9 @@ class Preview(base.Extractor):
             buffer = io.BytesIO()
             img.save(buffer, format='jpeg')
             # create a preview node
-            preview = node.Node(ns.bsn.Preview,
+            preview = nodes.Preview(
                 ucid=bsfs.uuid.UCID.from_bytes(buffer.getvalue()),
                 size=max_side,
-                source=subject,
                 )
             # yield triples
             yield subject, self.schema.predicate(ns.bse.preview), preview
diff --git a/bsie/lib/__init__.py b/bsie/lib/__init__.py
index f44fb74..daa806c 100644
--- a/bsie/lib/__init__.py
+++ b/bsie/lib/__init__.py
@@ -5,7 +5,6 @@ import typing
 # inner-module imports
 from .bsie import BSIE
 from .builder import PipelineBuilder
-from .naming_policy import DefaultNamingPolicy
 
 # exports
 __all__: typing.Sequence[str] = (
diff --git a/bsie/lib/bsie.py b/bsie/lib/bsie.py
index b02e707..9aa0bdb 100644
--- a/bsie/lib/bsie.py
+++ b/bsie/lib/bsie.py
@@ -3,10 +3,10 @@
 import typing
 
 # bsie imports
-from bsie.utils import bsfs, node, ns
+from bsie.utils import bsfs, ns
+from bsie.matcher import Matcher, nodes
 
 # inner-module imports
-from .naming_policy import NamingPolicy
 from .pipeline import Pipeline
 
 # exports
@@ -40,7 +40,7 @@ class BSIE():
             # pipeline.
             pipeline: Pipeline,
             # naming policy
-            naming_policy: NamingPolicy,
+            matcher: Matcher,
             # principals to extract at most. None implies all available w.r.t. extractors.
             collect: typing.Optional[typing.Iterable[bsfs.URI]] = None,
             # principals to discard.
@@ -48,7 +48,7 @@ class BSIE():
             ):
         # store pipeline and naming policy
         self._pipeline = pipeline
-        self._naming_policy = naming_policy
+        self._matcher = matcher
         # start off with available principals
         self._principals = {pred.uri for pred in self._pipeline.principals}
         # limit principals to specified ones by argument.
@@ -79,7 +79,7 @@ class BSIE():
             self,
             path: bsfs.URI,
             principals: typing.Optional[typing.Iterable[bsfs.URI]] = None,
-            ) -> typing.Iterator[typing.Tuple[node.Node, bsfs.URI, typing.Any]]:
+            ) -> typing.Iterator[typing.Tuple[nodes.Node, bsfs.URI, typing.Any]]:
         """Produce triples for a given *path*. Limit to *principals* if given."""
         # get requested principals.
         principals = set(principals) if principals is not None else self._principals
@@ -88,6 +88,6 @@ class BSIE():
         # predicate lookup
         principals = {self.schema.predicate(pred) for pred in principals}
         # invoke pipeline
-        yield from self._naming_policy(self._pipeline(path, principals))
+        yield from self._matcher(self._pipeline(path, principals))
 
 ## EOF ##
diff --git a/bsie/lib/naming_policy.py b/bsie/lib/naming_policy.py
deleted file mode 100644
index fbdbeb0..0000000
--- a/bsie/lib/naming_policy.py
+++ /dev/null
@@ -1,141 +0,0 @@
-
-# standard imports
-import abc
-import os
-import typing
-
-# external imports
-import urllib.parse
-
-# bsie imports
-from bsie.utils import bsfs, errors, ns
-from bsie.utils.node import Node
-
-# exports
-__all__: typing.Sequence[str] = (
-    'DefaultNamingPolicy',
-    )
-
-
-## code ##
-
-class NamingPolicy():
-    """Determine node uri's from node hints."""
-    def __call__(
-            self,
-            iterable: typing.Iterable[typing.Tuple[Node, bsfs.URI, typing.Any]],
-            ):
-        """Apply the policy on a triple iterator."""
-        return NamingPolicyIterator(self, iterable)
-
-    @abc.abstractmethod
-    def handle_node(self, node: Node) -> Node:
-        """Apply the policy on a node."""
-
-
-class NamingPolicyIterator():
-    """Iterates over triples, determines uris according to a *policy* as it goes."""
-
-    # source triple iterator.
-    _iterable: typing.Iterable[typing.Tuple[Node, bsfs.URI, typing.Any]]
-
-    # naming policy
-    _policy: NamingPolicy
-
-    def __init__(
-            self,
-            policy: NamingPolicy,
-            iterable: typing.Iterable[typing.Tuple[Node, bsfs.URI, typing.Any]],
-            ):
-        self._iterable = iterable
-        self._policy = policy
-
-    def __iter__(self):
-        for node, pred, value in self._iterable:
-            # handle subject
-            self._policy.handle_node(node)
-            # handle value
-            if isinstance(value, Node):
-                self._policy.handle_node(value)
-            # yield triple
-            yield node, pred, value
-
-
-class DefaultNamingPolicy(NamingPolicy):
-    """Compose URIs as <host/user/node_type#fragment>
-
-    What information is used as fragment depends on the node type.
-    Typically, the default is to use the "ucid" hint.
-    The fallback in all cases is to generate a random uuid.
-
-    Never changes previously assigned uris. Sets uris in-place.
-
-    """
-
-    def __init__(
-            self,
-            host: bsfs.URI,
-            user: str,
-            ):
-        self._prefix = bsfs.Namespace(os.path.join(host, user))
-        self._uuid = bsfs.uuid.UUID()
-
-    def handle_node(self, node: Node) -> Node:
-        if node.uri is not None:
-            return node
-        if node.node_type == ns.bsn.Entity:
-            return self.name_entity(node)
-        if node.node_type == ns.bsn.Preview:
-            return self.name_preview(node)
-        if node.node_type == ns.bsn.Tag:
-            return self.name_tag(node)
-        if node.node_type == ns.bsn.Face:
-            return self.name_face(node)
-        raise errors.ProgrammingError(f'no naming policy available for {node.node_type}')
-
-    def name_entity(self, node: Node) -> Node:
-        """Set a bsn:Entity node's uri fragment to its ucid."""
-        if 'ucid' in node.hints: # content id
-            fragment = node.hints['ucid']
-        else: # random name
-            fragment = self._uuid()
-        node.uri = getattr(self._prefix.file(), fragment)
-        return node
-
-    def name_preview(self, node: Node) -> Node:
-        """Set a bsn:Preview node's uri fragment to its ucid.
-        Uses its source fragment as fallback. Appends the size if provided.
-        """
-        fragment = None
-        if 'ucid' in node.hints: # content id
-            fragment = node.hints['ucid']
-        if fragment is None and 'source' in node.hints: # source id
-            self.handle_node(node.hints['source'])
-            fragment = node.hints['source'].uri.get('fragment', None)
-        if fragment is None: # random name
-            fragment = self._uuid()
-        if 'size' in node.hints: # append size
-            fragment += '_s' + str(node.hints['size'])
-        node.uri = getattr(self._prefix.preview(), fragment)
-        return node
-
-    def name_tag(self, node: Node) -> Node:
-        # NOTE: Must ensure to produce the same name for that tags with the same label.
-        if 'label' in node.hints: # tag label
-            fragment = urllib.parse.quote(node.hints['label'])
-        else: # random name
-            fragment = self._uuid()
-        # FIXME: match to existing tags in bsfs storage!
-        node.uri = getattr(self._prefix.tag(), fragment)
-        return node
-
-    def name_face(self, node: Node) -> Node:
-        if 'ucid' in node.hints: # content id
-            fragment = node.hints['ucid']
-        else: # random name
-            fragment = self._uuid()
-        node.uri = getattr(self._prefix.face(), fragment)
-        return node
-
-
-## EOF ##
diff --git a/bsie/lib/pipeline.py b/bsie/lib/pipeline.py
index 30fd6fd..98d9cc8 100644
--- a/bsie/lib/pipeline.py
+++ b/bsie/lib/pipeline.py
@@ -6,8 +6,9 @@ import typing
 
 # bsie imports
 from bsie.extractor import Extractor
+from bsie.matcher import nodes
 from bsie.reader import Reader
-from bsie.utils import bsfs, errors, node, ns
+from bsie.utils import bsfs, errors, ns
 
 # exports
 __all__: typing.Sequence[str] = (
@@ -85,7 +86,7 @@ class Pipeline():
             self,
             path: bsfs.URI,
             principals: typing.Optional[typing.Iterable[bsfs.schema.Predicate]] = None,
-            ) -> typing.Iterator[typing.Tuple[node.Node, bsfs.schema.Predicate, typing.Any]]:
+            ) -> typing.Iterator[typing.Tuple[nodes.Node, bsfs.schema.Predicate, typing.Any]]:
         """Extract triples from the file at *path*. Optionally, limit triples to *principals*."""
         # get principals
         principals = set(principals) if principals is not None else set(self.schema.predicates())
@@ -104,9 +105,7 @@ class Pipeline():
             rdr2ext[rdr].add(ext)
 
         # create subject for file
-        subject = node.Node(ns.bsn.Entity,
-            ucid=bsfs.uuid.UCID.from_path(path),
-            )
+        subject = nodes.Entity(ucid=bsfs.uuid.UCID.from_path(path))
 
         # extract information
         for rdr, extrs in rdr2ext.items():
diff --git a/bsie/matcher/__init__.py b/bsie/matcher/__init__.py
new file mode 100644
index 0000000..836bacf
--- /dev/null
+++ b/bsie/matcher/__init__.py
@@ -0,0 +1,17 @@
+
+# standard imports
+import typing
+
+# inner-module imports
+from . import nodes
+from .default_matcher import DefaultMatcher
+from .matcher import Matcher
+
+# exports
+__all__: typing.Sequence[str] = (
+    'DefaultMatcher',
+    'Matcher',
+    'nodes',
+    )
+
+## EOF ##
diff --git a/bsie/matcher/default_matcher.py b/bsie/matcher/default_matcher.py
new file mode 100644
index 0000000..94bbe2c
--- /dev/null
+++ b/bsie/matcher/default_matcher.py
@@ -0,0 +1,76 @@
+
+# standard imports
+import os
+import typing
+import urllib
+
+# bsie imports
+from bsie.utils import bsfs
+
+# inner-module imports
+from . import nodes
+from .matcher import Matcher
+
+# exports
+__all__: typing.Sequence[str] = (
+    'DefaultMatcher',
+    )
+
+
+## code ##
+
+class DefaultMatcher(Matcher):
+    """Compose URIs as <host/user/node_type#fragment>
+
+    What information is used as fragment depends on the node type.
+    Typically, the default is to use the "ucid" hint.
+    The fallback in all cases is to generate a random uuid.
+
+    Never changes previously assigned uris. Sets uris in-place.
+
+    """
+
+    def __init__(
+            self,
+            host: bsfs.URI,
+            user: str,
+            ):
+        self._prefix = bsfs.Namespace(os.path.join(host, user))
+
+    def match_node(self, node: nodes.Node) -> nodes.Node:
+        if node.uri is not None:
+            return node
+        if isinstance(node, nodes.Entity):
+            return self.match_entity(node)
+        if isinstance(node, nodes.Preview):
+            return self.match_preview(node)
+        if isinstance(node, nodes.Tag):
+            return self.match_tag(node)
+        if isinstance(node, nodes.Face):
+            return self.match_face(node)
+        raise ValueError(f'no matching policy available for bsfs.typename{node}')
+
+    def match_entity(self, node: nodes.Entity) -> nodes.Entity:
+        """Set a bsn:Entity node's uri fragment to its ucid."""
+        node.uri = getattr(self._prefix.file(), node.ucid)
+        return node
+
+    def match_preview(self, node: nodes.Preview) -> nodes.Preview:
+        """Set a bsn:Preview node's uri fragment to its ucid and size suffix."""
+        fragment = node.ucid + '_s' + str(node.size)
+        node.uri = getattr(self._prefix.preview(), fragment)
+        return node
+
+    def match_tag(self, node: nodes.Tag) -> nodes.Tag:
+        """Set a bsn:Tag node's uri to its label."""
+        # FIXME: match to existing tags in bsfs storage?!
+        fragment = urllib.parse.quote(node.label)
+        node.uri = getattr(self._prefix.tag(), fragment)
+        return node
+
+    def match_face(self, node: nodes.Face) -> nodes.Face:
+        """Set a bsn:Face node's uri to its ucid."""
+        node.uri = getattr(self._prefix.face(), node.ucid)
+        return node
+
+## EOF ##
diff --git a/bsie/matcher/matcher.py b/bsie/matcher/matcher.py
new file mode 100644
index 0000000..a89626f
--- /dev/null
+++ b/bsie/matcher/matcher.py
@@ -0,0 +1,61 @@
+
+# standard imports
+import abc
+import typing
+
+# bsie imports
+from bsie.utils import bsfs
+
+# inner-module imports
+from . import nodes
+
+# exports
+__all__: typing.Sequence[str] = (
+    'Matcher',
+    )
+
+
+## code ##
+
+class Matcher():
+    """Determine node uri's from node hints."""
+    def __call__(
+            self,
+            iterable: typing.Iterable[typing.Tuple[nodes.Node, bsfs.URI, typing.Any]],
+            ):
+        """Apply the matcher on a triple iterator."""
+        return MatcherIterator(self, iterable)
+
+    @abc.abstractmethod
+    def match_node(self, node: nodes.Node) -> nodes.Node:
+        """Apply the matcher on a node."""
+
+
+class MatcherIterator():
+    """Iterates over triples, determines uris according to a *matcher* as it goes."""
+
+    # source triple iterator.
+    _iterable: typing.Iterable[typing.Tuple[nodes.Node, bsfs.URI, typing.Any]]
+
+    # node matcher
+    _matcher: Matcher
+
+    def __init__(
+            self,
+            matcher: Matcher,
+            iterable: typing.Iterable[typing.Tuple[nodes.Node, bsfs.URI, typing.Any]],
+            ):
+        self._iterable = iterable
+        self._matcher = matcher
+
+    def __iter__(self):
+        for node, pred, value in self._iterable:
+            # handle subject
+            self._matcher.match_node(node)
+            # handle value
+            if isinstance(value, nodes.Node):
+                self._matcher.match_node(value)
+            # yield triple
+            yield node, pred, value
+
+## EOF ##
diff --git a/bsie/matcher/nodes.py b/bsie/matcher/nodes.py
new file mode 100644
index 0000000..047e7d1
--- /dev/null
+++ b/bsie/matcher/nodes.py
@@ -0,0 +1,49 @@
+
+# standard imports
+from dataclasses import dataclass
+import typing
+
+# bsie imports
+from bsie.utils import bsfs, ns
+
+# exports
+__all__: typing.Sequence[str] = (
+    'Entity',
+    'Face',
+    'Node',
+    'Person',
+    'Preview',
+    'Tag',
+    )
+
+@dataclass(kw_only=True, unsafe_hash=True)
+class Node: # pylint: disable=missing-class-docstring
+    # FIXME: Only allow changes to uri after init
+    uri: typing.Optional[bsfs.URI] = None
+
+@dataclass(kw_only=True, unsafe_hash=True)
+class Entity(Node): # pylint: disable=missing-class-docstring
+    node_type: bsfs.URI = ns.bsn.Entity
+    ucid: str
+
+@dataclass(kw_only=True, unsafe_hash=True)
+class Face(Node): # pylint: disable=missing-class-docstring
+    node_type: bsfs.URI = ns.bsn.Face
+    ucid: str
+
+@dataclass(kw_only=True, unsafe_hash=True)
+class Person(Node): # pylint: disable=missing-class-docstring
+    node_type: bsfs.URI = ns.bsn.Person
+
+@dataclass(kw_only=True, unsafe_hash=True)
+class Preview(Node): # pylint: disable=missing-class-docstring
+    node_type: bsfs.URI = ns.bsn.Preview
+    ucid: str
+    size: int
+
+@dataclass(kw_only=True, unsafe_hash=True)
+class Tag(Node): # pylint: disable=missing-class-docstring
+    node_type: bsfs.URI = ns.bsn.Tag
+    label: str
+
+## EOF ##
diff --git a/bsie/reader/face.py b/bsie/reader/face.py
index c5374e0..e43b93f 100644
--- a/bsie/reader/face.py
+++ b/bsie/reader/face.py
@@ -9,7 +9,7 @@ import PIL.Image
 import torch
 
 # bsie imports
-from bsie.utils import bsfs, errors, node, ns
+from bsie.utils import bsfs, errors, ns
 
 # inner-module imports
 from . import base
diff --git a/bsie/utils/__init__.py b/bsie/utils/__init__.py
index 4f08604..0c96139 100644
--- a/bsie/utils/__init__.py
+++ b/bsie/utils/__init__.py
@@ -7,7 +7,6 @@ import typing
 from . import bsfs
 from . import filematcher
 from . import namespaces as ns
-from . import node
 from .filewalker import list_files
 from .loading import safe_load, unpack_qualified_name
 
@@ -15,7 +14,6 @@ from .loading import safe_load, unpack_qualified_name
 __all__: typing.Sequence[str] = (
     'bsfs',
     'filematcher',
-    'node',
     'ns',
     'safe_load',
     'unpack_qualified_name',
diff --git a/bsie/utils/node.py b/bsie/utils/node.py
deleted file mode 100644
index fa34b2e..0000000
--- a/bsie/utils/node.py
+++ /dev/null
@@ -1,66 +0,0 @@
-"""Lighweight Node to bridge to BSFS.
-"""
-# standard imports
-import typing
-
-# bsie imports
-from bsie.utils import bsfs
-
-# exports
-__all__: typing.Sequence[str] = (
-    'Node',
-    )
-
-
-## code ##
-
-class Node():
-    """Lightweight Node, disconnected from any bsfs structures.
-
-    In most cases, provide *hints* and leave setting the uri to a node
-    naming policy. Only provide an *uri* if it is absolutely determined.
-
-    """
-
-    # node type.
-    node_type: bsfs.URI
-
-    # node URI.
-    uri: typing.Optional[bsfs.URI]
-
-    # node naming hints.
-    hits: dict
-
-    def __init__(
-            self,
-            node_type: bsfs.URI,
-            uri: typing.Optional[bsfs.URI] = None,
-            **uri_hints,
-            ):
-        # assign members
-        self.node_type = bsfs.URI(node_type)
-        self.hints = uri_hints
-        self.uri = uri
-
-    def __eq__(self, other: typing.Any) -> bool:
-        """Compare two Node instances based on type and uri.
-        Compares hits only if the uri is not yet specified.
-        """
-        return isinstance(other, Node) \
-            and other.node_type == self.node_type \
-            and other.uri == self.uri \
-            and (self.uri is not None or self.hints == other.hints)
-
-    def __hash__(self) -> int:
-        identifier = self.uri
-        if identifier is None:
-            identifier = tuple((key, self.hints[key]) for key in sorted(self.hints))
-        return hash((type(self), self.node_type, identifier))
-
-    def __str__(self) -> str:
-        return f'{bsfs.typename(self)}({self.node_type}, {self.uri})'
-
-    def __repr__(self) -> str:
-        return f'{bsfs.typename(self)}({self.node_type}, {self.uri})'
-
-## EOF ##
diff --git a/test/extractor/generic/test_constant.py b/test/extractor/generic/test_constant.py
index 77ee02b..ea18385 100644
--- a/test/extractor/generic/test_constant.py
+++ b/test/extractor/generic/test_constant.py
@@ -3,7 +3,8 @@
 import unittest
 
 # bsie imports
-from bsie.utils import node as _node, ns
+from bsie.matcher import nodes
+from bsie.utils import ns
 
 # objects to test
 from bsie.extractor.generic.constant import Constant
@@ -28,7 +29,7 @@ class TestConstant(unittest.TestCase):
             (ns.bse.comment, 'the quick brown fox jumps over the lazy dog.'),
             ]
         ext = Constant(schema, tuples)
-        node = _node.Node(ns.bsn.Entity, '') # Blank node
+        node = nodes.Entity(ucid='abc123') # Blank node
         p_author = ext.schema.predicate(ns.bse.author)
         p_comment = ext.schema.predicate(ns.bse.comment)
         entity = ext.schema.node(ns.bsfs.Node).child(ns.bsn.Entity)
diff --git a/test/extractor/generic/test_path.py b/test/extractor/generic/test_path.py
index 569703d..132b670 100644
--- a/test/extractor/generic/test_path.py
+++ b/test/extractor/generic/test_path.py
@@ -5,7 +5,8 @@ import unittest
 
 # bsie imports
 from bsie.extractor import base
-from bsie.utils import bsfs, node as _node, ns
+from bsie.matcher import nodes
+from bsie.utils import bsfs, ns
 
 # objects to test
 from bsie.extractor.generic.path import Path
@@ -40,7 +41,7 @@ class TestPath(unittest.TestCase):
 
     def test_extract(self):
         ext = Path()
-        node = _node.Node(ns.bsn.Entity, '') # Blank node
+        node = nodes.Entity(ucid='abc123')
         content = '/tmp/foo/bar'
         p_filename = ext.schema.predicate(ns.bse.filename)
         p_dirname = ext.schema.predicate(ns.bse.dirname)
@@ -68,7 +69,7 @@ class TestPath(unittest.TestCase):
         self.assertSetEqual(set(ext.extract(node, '', (p_filename, p_dirname))),
             {(node, p_filename, ''), (node, p_dirname, os.path.dirname(os.getcwd()))})
         # errors are suppressed
-        self.assertSetEqual(set(ext.extract(node, None, (p_filename, ))), set())
+        self.assertSetEqual(set(ext.extract(node, None, (p_filename, p_dirname))), set())
 
 
 ## main ##
diff --git a/test/extractor/generic/test_stat.py b/test/extractor/generic/test_stat.py
index 0e83e24..38a9c0c 100644
--- a/test/extractor/generic/test_stat.py
+++ b/test/extractor/generic/test_stat.py
@@ -5,7 +5,8 @@ import unittest
 
 # bsie imports
 from bsie.extractor import base
-from bsie.utils import bsfs, node as _node, ns
+from bsie.matcher import nodes
+from bsie.utils import bsfs, ns
 
 # objects to test
 from bsie.extractor.generic.stat import Stat
@@ -34,7 +35,7 @@ class TestStat(unittest.TestCase):
 
     def test_extract(self):
         ext = Stat()
-        node = _node.Node(ns.bsn.Entity, '') # Blank node
+        node = nodes.Entity(ucid='abc123')
         content = os.stat(__file__)
         p_filesize = ext.schema.predicate(ns.bse.filesize)
         entity = ext.schema.node(ns.bsfs.Node).child(ns.bsn.Entity)
diff --git a/test/extractor/image/face/test_detect.py b/test/extractor/image/face/test_detect.py
index 92375a2..89a3461 100644
--- a/test/extractor/image/face/test_detect.py
+++ b/test/extractor/image/face/test_detect.py
@@ -8,8 +8,9 @@ import unittest
 
 # bsie imports
 from bsie.extractor import base
+from bsie.matcher import nodes
 from bsie.reader.face import FaceExtract
-from bsie.utils import bsfs, node as _node, ns
+from bsie.utils import bsfs, ns
 
 # objects to test
 from bsie.extractor.image.face.detect import FaceDetect, bsf
@@ -31,10 +32,11 @@ class TestFaceDetect(unittest.TestCase):
             # setup
             rdr = FaceExtract()
             ext = FaceDetect()
-            subject = _node.Node(ns.bsfs.Entity)
+            subject = nodes.Entity(ucid='abc123')
             content = rdr(os.path.join(os.path.dirname(__file__), 'testface1.jpg'))
             principals = set(ext.principals)
-            face = _node.Node(ns.bsn.Face, ucid='2a7203c1515e0caa66a7461452c0b4552f1433a613cb3033e59ed2361790ad45')
+            face = nodes.Face(
+                ucid='2a7203c1515e0caa66a7461452c0b4552f1433a613cb3033e59ed2361790ad45')
             triples = list(ext.extract(subject, content, principals))
             # principals is bse:face
             self.assertSetEqual(principals, {ext.schema.predicate(ns.bse.face)})
diff --git a/test/extractor/image/face/test_identify.py b/test/extractor/image/face/test_identify.py
index dde41db..2d52353 100644
--- a/test/extractor/image/face/test_identify.py
+++ b/test/extractor/image/face/test_identify.py
@@ -10,8 +10,9 @@ import requests
 
 # bsie imports
 from bsie.extractor import base
+from bsie.matcher import nodes
 from bsie.reader.face import FaceExtract
-from bsie.utils import bsfs, node as _node, ns
+from bsie.utils import bsfs, ns
 
 # objects to test
 from bsie.extractor.image.face.identify import FaceIdentify, bsf
@@ -106,11 +107,12 @@ class TestFaceIdentify(unittest.TestCase):
                 os.path.join(os.path.dirname(__file__), 'ref_embeds.npy'),
                 os.path.join(os.path.dirname(__file__), 'ref_mapping.csv'),
                 )
-            subject = _node.Node(ns.bsfs.Entity)
+            subject = nodes.Entity(ucid='abc123')
             content = rdr(os.path.join(os.path.dirname(__file__), 'testface1.jpg'))
             principals = set(ext.principals)
-            face = _node.Node(ns.bsn.Face, ucid='2a7203c1515e0caa66a7461452c0b4552f1433a613cb3033e59ed2361790ad45')
-            person = _node.Node(ns.bsn.Person, uri='https://example.com/user/Angelina_Jolie')
+            face = nodes.Face(
+                ucid='2a7203c1515e0caa66a7461452c0b4552f1433a613cb3033e59ed2361790ad45')
+            person = nodes.Person(uri='https://example.com/user/Angelina_Jolie')
             triples = list(ext.extract(subject, content, principals))
             # principls is bse:face, bsf:depicts
             self.assertSetEqual(set(ext.principals), {
@@ -128,10 +130,11 @@ class TestFaceIdentify(unittest.TestCase):
             self.assertListEqual(list(ext.extract(subject, content, principals)), [])
             # identifies the correct person despite somewhat similar options
             content = rdr(os.path.join(os.path.dirname(__file__), 'testface3.jpg'))
-            face = _node.Node(ns.bsn.Face, ucid='f61fac01ef686ee05805afef1e7a10ba54c30dc1aa095d9e77d79ccdfeb40dc5')
+            face = nodes.Face(
+                ucid='f61fac01ef686ee05805afef1e7a10ba54c30dc1aa095d9e77d79ccdfeb40dc5')
             triples = list(ext.extract(subject, content, principals))
             self.assertEqual(len(triples), 2)
-            person = _node.Node(ns.bsn.Person, uri='https://example.com/user/Paul_Rudd')
+            person = nodes.Person(uri='https://example.com/user/Paul_Rudd')
             self.assertIn((subject, ext.schema.predicate(ns.bse.face), face), triples)
             self.assertIn((face, ext.schema.predicate(bsf.depicts), person), triples)
             # no triples on principal mismatch
diff --git a/test/extractor/image/test_colors_spatial.py b/test/extractor/image/test_colors_spatial.py
index 902ab6d..1c87bb7 100644
--- a/test/extractor/image/test_colors_spatial.py
+++ b/test/extractor/image/test_colors_spatial.py
@@ -8,7 +8,8 @@ import PIL.Image
 
 # bsie imports
 from bsie.extractor import base
-from bsie.utils import bsfs, ns, node as _node
+from bsie.matcher import nodes
+from bsie.utils import bsfs, ns
 
 # objects to test
 from bsie.extractor.image.colors_spatial import ColorsSpatial
@@ -73,7 +74,7 @@ class TestColorsSpatial(unittest.TestCase):
     def test_extract(self):
         ext = ColorsSpatial(2,2,2)
         img = PIL.Image.open(os.path.join(os.path.dirname(__file__), 'testimage.jpg'))
-        node = _node.Node(ns.bsn.Entity, bsfs.URI('http://example.com/entity#1234'))
+        node = nodes.Entity(ucid='1234')
         principals = set(ext.principals)
         self.assertEqual(len(principals), 1)
         # valid invocation yields feature
diff --git a/test/extractor/image/test_iptc.py b/test/extractor/image/test_iptc.py
index 5fa763d..7efbdfe 100644
--- a/test/extractor/image/test_iptc.py
+++ b/test/extractor/image/test_iptc.py
@@ -4,7 +4,8 @@ import unittest
 
 # bsie imports
 from bsie.extractor import base
-from bsie.utils import bsfs, node as _node, ns
+from bsie.matcher import nodes
+from bsie.utils import bsfs, ns
 
 # objects to test
 from bsie.extractor.image.iptc import Iptc
@@ -36,29 +37,29 @@ class TestIptc(unittest.TestCase):
 
     def test_extract(self):
         ext = Iptc()
-        node = _node.Node(ns.bsfs.File, '') # Blank node
+        subject = nodes.Entity(ucid='abc123')
         content = {
             'Iptc.Application2.Keywords': ['hello', 'world'],
             'Iptc.Application2.RecordVersion': '4',
             }
         # target tags
-        t_hello = _node.Node(ns.bsn.Tag, label='hello')
-        t_world = _node.Node(ns.bsn.Tag, label='world')
+        t_hello = nodes.Tag(label='hello')
+        t_world = nodes.Tag(label='world')
 
         # invalid principals are ignored
-        self.assertSetEqual(set(ext.extract(node, content, {ns.bse.filename})), set())
+        self.assertSetEqual(set(ext.extract(subject, content, {ns.bse.filename})), set())
         # extract finds all relevant information
-        self.assertSetEqual(set(ext.extract(node, content, {ext.schema.predicate(ns.bse.tag)})), {
-            (node, ext.schema.predicate(ns.bse.tag), t_hello),
-            (node, ext.schema.predicate(ns.bse.tag), t_world),
+        self.assertSetEqual(set(ext.extract(subject, content, {ext.schema.predicate(ns.bse.tag)})), {
+            (subject, ext.schema.predicate(ns.bse.tag), t_hello),
+            (subject, ext.schema.predicate(ns.bse.tag), t_world),
             (t_hello, ext.schema.predicate(ns.bst.label), 'hello'),
             (t_world, ext.schema.predicate(ns.bst.label), 'world'),
             })
 
         # empty content is acceptable
-        self.assertSetEqual(set(ext.extract(node, {}, set(ext.principals))), set())
+        self.assertSetEqual(set(ext.extract(subject, {}, set(ext.principals))), set())
         # no principals is acceptable
-        self.assertSetEqual(set(ext.extract(node, content, set())), set())
+        self.assertSetEqual(set(ext.extract(subject, content, set())), set())
 
 
 ## main ##
diff --git a/test/extractor/image/test_photometrics.py b/test/extractor/image/test_photometrics.py
index fb219e2..1316618 100644
--- a/test/extractor/image/test_photometrics.py
+++ b/test/extractor/image/test_photometrics.py
@@ -4,7 +4,8 @@ import unittest
 
 # bsie imports
 from bsie.extractor import base
-from bsie.utils import bsfs, node as _node, ns
+from bsie.matcher import nodes
+from bsie.utils import bsfs, ns
 
 # objects to test
 from bsie.extractor.image.photometrics import Exif, _gps_to_dec
@@ -55,7 +56,7 @@ class TestExif(unittest.TestCase):
 
     def test_extract(self):
         ext = Exif()
-        node = _node.Node(ns.bsfs.File, '') # Blank node
+        node = nodes.Entity(ucid='abc123')
         content = {
             'Exif.Photo.ExposureTime': '10/600',
             'Exif.Photo.FNumber': '48/10',
diff --git a/test/extractor/test_preview.py b/test/extractor/test_preview.py
index 6526783..7b60520 100644
--- a/test/extractor/test_preview.py
+++ b/test/extractor/test_preview.py
@@ -9,7 +9,8 @@ import PIL.Image
 
 # bsie imports
 from bsie.extractor import base
-from bsie.utils import bsfs, node as _node, ns
+from bsie.matcher import nodes
+from bsie.utils import bsfs, ns
 from bsie.reader.preview import Preview as Reader
 
 # objects to test
@@ -69,7 +70,7 @@ class TestPreview(unittest.TestCase):
     def test_extract(self):
         # setup dependents
         rdr = Reader()
-        subject = _node.Node(ns.bsn.Entity)
+        subject = nodes.Entity(ucid='abc123')
         path = os.path.join(os.path.dirname(__file__), 'testimage.jpg')
 
         # setup extractor
diff --git a/test/lib/test_bsie.py b/test/lib/test_bsie.py
index 6586e58..a154477 100644
--- a/test/lib/test_bsie.py
+++ b/test/lib/test_bsie.py
@@ -6,9 +6,10 @@ import unittest
 # bsie imports
 from bsie.extractor import ExtractorBuilder
 from bsie.extractor.base import SCHEMA_PREAMBLE
-from bsie.lib import PipelineBuilder, DefaultNamingPolicy
+from bsie.lib import PipelineBuilder
+from bsie.matcher import nodes, DefaultMatcher
 from bsie.reader import ReaderBuilder
-from bsie.utils import bsfs, node, ns
+from bsie.utils import bsfs, ns
 
 # objects to test
 from bsie.lib.bsie import BSIE
@@ -35,13 +36,13 @@ class TestBSIE(unittest.TestCase):
                 )},
             ])
         # build pipeline
-        self.naming_policy = DefaultNamingPolicy(host='http://example.com/local', user='me')
+        self.matcher = DefaultMatcher(host='http://example.com/local', user='me')
         pbuild = PipelineBuilder(rbuild, ebuild)
         self.pipeline = pbuild.build()
 
     def test_construction(self):
         # only pipeline and naming policy
-        lib = BSIE(self.pipeline, self.naming_policy)
+        lib = BSIE(self.pipeline, self.matcher)
         self.assertSetEqual(set(lib.principals), {
             ns.bse.filename,
             ns.bse.dirname,
@@ -71,7 +72,7 @@ class TestBSIE(unittest.TestCase):
             '''))
 
         # specify collect
-        lib = BSIE(self.pipeline, self.naming_policy, collect={
+        lib = BSIE(self.pipeline, self.matcher, collect={
             ns.bse.filesize,
             ns.bse.author,
             ns.bse.inexistent,
@@ -92,7 +93,7 @@ class TestBSIE(unittest.TestCase):
                 bsfs:unique "true"^^xsd:boolean .
             '''))
         # empty collect is disregarded
-        lib = BSIE(self.pipeline, self.naming_policy, collect={})
+        lib = BSIE(self.pipeline, self.matcher, collect={})
         self.assertSetEqual(set(lib.principals), {
             ns.bse.filename,
             ns.bse.dirname,
@@ -123,7 +124,7 @@ class TestBSIE(unittest.TestCase):
             '''))
 
         # specify discard
-        lib = BSIE(self.pipeline, self.naming_policy, discard={
+        lib = BSIE(self.pipeline, self.matcher, discard={
             ns.bse.filesize,
             ns.bse.filename,
             ns.bse.inexistent,
@@ -151,7 +152,7 @@ class TestBSIE(unittest.TestCase):
             '''))
 
         # specify collect and discard
-        lib = BSIE(self.pipeline, self.naming_policy,
+        lib = BSIE(self.pipeline, self.matcher,
             collect={ns.bse.filesize, ns.bse.author, ns.bse.foo, ns.bse.bar},
             discard={ns.bse.author, ns.bse.foo, ns.bse.foobar},
             )
@@ -168,7 +169,7 @@ class TestBSIE(unittest.TestCase):
 
     def test_from_file(self):
         # setup
-        lib = BSIE(self.pipeline, self.naming_policy)
+        lib = BSIE(self.pipeline, self.matcher)
         self.assertSetEqual(set(lib.principals), {
             ns.bse.filesize,
             ns.bse.filename,
@@ -176,7 +177,10 @@ class TestBSIE(unittest.TestCase):
             ns.bse.author,
             })
         content_hash = 'a948904f2f0f479b8f8197694b30184b0d2ed1c1cd2a1ec0fb85d299a192a447'
-        subject = node.Node(ns.bsn.Entity, uri=f'http://example.com/local/me/file#{content_hash}')
+        subject = nodes.Entity(
+            uri=f'http://example.com/local/me/file#{content_hash}',
+            ucid=content_hash,
+            )
         testfile = os.path.join(os.path.dirname(__file__), 'testfile.t')
 
         # from_file extracts all available triples
diff --git a/test/lib/test_naming_policy.py b/test/lib/test_naming_policy.py
deleted file mode 100644
index a078fbd..0000000
--- a/test/lib/test_naming_policy.py
+++ /dev/null
@@ -1,158 +0,0 @@
-
-# standard imports
-import unittest
-
-# bsie imports
-from bsie.utils import ns, errors
-from bsie.utils.bsfs import URI
-from bsie.utils.node import Node
-
-# objects to test
-from bsie.lib.naming_policy import NamingPolicy, NamingPolicyIterator, DefaultNamingPolicy
-
-
-
-## code ##
-
-class TestDefaultNamingPolicy(unittest.TestCase):
-
-    def test_handle_node(self):
-        # setup
-        policy = DefaultNamingPolicy('http://example.com', 'me')
-        # handle_node doesn't modify existing uris
-        self.assertEqual(policy.handle_node(
-            Node(ns.bsn.Invalid, uri='http://example.com/you/foo#bar')).uri,
-            URI('http://example.com/you/foo#bar'))
-        # processes bsn:Entity
-        self.assertEqual(policy.handle_node(
-            Node(ns.bsn.Entity, ucid='abc123cba')).uri,
-            URI('http://example.com/me/file#abc123cba'))
-        # processes bsn:Preview
-        self.assertEqual(policy.handle_node(
-            Node(ns.bsn.Preview, ucid='abc123cba', size=123)).uri,
-            URI('http://example.com/me/preview#abc123cba_s123'))
-        # processes bsn:Tag
-        self.assertEqual(policy.handle_node(
-            Node(ns.bsn.Tag, label='hello')).uri,
-            URI('http://example.com/me/tag#hello'))
-        # processes bsn:Face
-        self.assertEqual(policy.handle_node(
-            Node(ns.bsn.Face, ucid='hello')).uri,
-            URI('http://example.com/me/face#hello'))
-        # raises an exception on unknown types
-        self.assertRaises(errors.ProgrammingError, policy.handle_node,
-            Node(ns.bsn.Invalid, ucid='abc123cba', size=123))
-
-    def test_name_entity(self):
-        # setup
-        policy = DefaultNamingPolicy('http://example.com', 'me')
-        # name_entity uses ucid
-        self.assertEqual(policy.name_entity(
-            Node(ns.bsn.Entity, ucid='123abc321')).uri,
-            URI('http://example.com/me/file#123abc321'))
-        # name_entity falls back to a random guid
-        self.assertTrue(policy.name_entity(
-            Node(ns.bsn.Entity)).uri.startswith('http://example.com/me/file#'))
-
-    def test_name_preview(self):
-        # setup
-        policy = DefaultNamingPolicy('http://example.com', 'me')
-        # name_preview uses ucid
-        self.assertEqual(policy.name_preview(
-            Node(ns.bsn.Preview, ucid='123abc321')).uri,
-            URI('http://example.com/me/preview#123abc321'))
-        self.assertEqual(policy.name_preview(
-            Node(ns.bsn.Preview, ucid='123abc321', size=400)).uri,
-            URI('http://example.com/me/preview#123abc321_s400'))
-        # name_preview uses source
-        self.assertEqual(policy.name_preview(
-            Node(ns.bsn.Preview, source=Node(ns.bsn.Entity, ucid='123file321'))).uri,
-            URI('http://example.com/me/preview#123file321'))
-        self.assertEqual(policy.name_preview(
-            Node(ns.bsn.Preview, source=Node(ns.bsn.Entity, ucid='123file321'), size=300)).uri,
-            URI('http://example.com/me/preview#123file321_s300'))
-        # name_preview falls back to a random guid
-        self.assertTrue(policy.name_preview(
-            Node(ns.bsn.Preview)).uri.startswith('http://example.com/me/preview#'))
-        self.assertTrue(policy.name_preview(
-            Node(ns.bsn.Preview, size=200)).uri.startswith('http://example.com/me/preview#'))
-        self.assertTrue(policy.name_preview(
-            Node(ns.bsn.Preview, size=200)).uri.endswith('_s200'))
-
-    def test_name_tag(self):
-        # setup
-        policy = DefaultNamingPolicy('http://example.com', 'me')
-        # name_tag uses label
-        self.assertEqual(policy.name_tag(
-            Node(ns.bsn.Tag, label='hello')).uri,
-            URI('http://example.com/me/tag#hello'))
-        # name_tag matches the label
-        self.assertEqual(
-            policy.name_tag(Node(ns.bsn.Tag, label='world')),
-            policy.name_tag(Node(ns.bsn.Tag, label='world')),
-            )
-        self.assertNotEqual(
-            policy.name_tag(Node(ns.bsn.Tag, label='hello')),
-            policy.name_tag(Node(ns.bsn.Tag, label='world')),
-            )
-        # label can include characters that are not valid for an uri
-        self.assertEqual(policy.name_tag(
-            Node(ns.bsn.Preview, label='hello world { foo bar ] ')).uri,
-            URI('http://example.com/me/tag#hello%20world%20%7B%20foo%20bar%20%5D%20'))
-        # name_tag falls back to a random guid
-        self.assertTrue(policy.name_tag(
-            Node(ns.bsn.Tag,)).uri.startswith('http://example.com/me/tag#'))
-
-    def test_name_face(self):
-        # setup
-        policy = DefaultNamingPolicy('http://example.com', 'me')
-        # name_face uses ucid
-        self.assertEqual(policy.name_face(
-            Node(ns.bsn.Face, ucid='hello_world')).uri,
-            URI('http://example.com/me/face#hello_world'))
-        # name_face falls back to a random guid
-        self.assertTrue(policy.name_face(
-            Node(ns.bsn.Face)).uri.startswith('http://example.com/me/face#'))
-
-
-class TestNamingPolicyIterator(unittest.TestCase):
-
-    def test_call(self): # NOTE: We test NamingPolicy.__call__ here
-        # setup
-        policy = DefaultNamingPolicy('http://example.com', 'me')
-        # call accepts list
-        triples = [('node', 'pred', 'value'), ('node', 'pred', 'value')]
-        it = policy(triples)
-        self.assertIsInstance(it, NamingPolicyIterator)
-        self.assertEqual(it._iterable, triples)
-        self.assertEqual(it._policy, policy)
-        # call accepts iterator
-        triples = iter([('node', 'pred', 'value'), ('node', 'pred', 'value')])
-        it = policy(triples)
-        self.assertIsInstance(it, NamingPolicyIterator)
-        self.assertEqual(it._iterable, triples)
-        self.assertEqual(it._policy, policy)
-
-    def test_iter(self):
-        # setup
-        policy = DefaultNamingPolicy('http://example.com', 'me')
-        triples = [
-            (Node(ns.bsn.Entity, ucid='foo'), 'predA', 'hello'),
-            (Node(ns.bsn.Preview, ucid='bar'), 'predB', 1234),
-            (Node(ns.bsn.Preview, ucid='hello'), 'predC', Node(ns.bsn.Entity, ucid='world'))
-            ]
-        # handles nodes, handles values, ignores predicate
-        self.assertListEqual(list(policy(triples)), [
-            (Node(ns.bsn.Entity, uri='http://example.com/me/file#foo'), 'predA', 'hello'),
-            (Node(ns.bsn.Preview, uri='http://example.com/me/preview#bar'), 'predB', 1234),
-            (Node(ns.bsn.Preview, uri='http://example.com/me/preview#hello'), 'predC',
-                Node(ns.bsn.Entity, uri='http://example.com/me/file#world')),
-            ])
-
-
-## main ##
-
-if __name__ == '__main__':
-    unittest.main()
-
-## EOF ##
diff --git a/test/lib/test_pipeline.py b/test/lib/test_pipeline.py
index 8d836fd..05c6768 100644
--- a/test/lib/test_pipeline.py
+++ b/test/lib/test_pipeline.py
@@ -5,7 +5,8 @@ import os
 import unittest
 
 # bsie imports
-from bsie.utils import bsfs, errors, node, ns
+from bsie.matcher import nodes
+from bsie.utils import bsfs, errors, ns
 import bsie.extractor.generic.constant
 import bsie.extractor.generic.path
 import bsie.extractor.generic.stat
@@ -84,7 +85,7 @@ class TestPipeline(unittest.TestCase):
         pipeline = Pipeline(self.ext2rdr)
         # build objects for tests
         content_hash = 'a948904f2f0f479b8f8197694b30184b0d2ed1c1cd2a1ec0fb85d299a192a447'
-        subject = node.Node(ns.bsn.Entity, ucid=content_hash)
+        subject = nodes.Entity(ucid=content_hash)
         testfile = os.path.join(os.path.dirname(__file__), 'testfile.t')
         p_filename = pipeline.schema.predicate(ns.bse.filename)
         p_dirname = pipeline.schema.predicate(ns.bse.dirname)
diff --git a/test/matcher/__init__.py b/test/matcher/__init__.py
new file mode 100644
index 0000000..e69de29
--- /dev/null
+++ b/test/matcher/__init__.py
diff --git a/test/matcher/test_default_matcher.py b/test/matcher/test_default_matcher.py
new file mode 100644
index 0000000..2ed371f
--- /dev/null
+++ b/test/matcher/test_default_matcher.py
@@ -0,0 +1,104 @@
+
+# standard imports
+from dataclasses import dataclass
+import unittest
+
+# bsie imports
+from bsie.matcher import nodes
+from bsie.utils import ns, errors
+from bsie.utils.bsfs import URI
+
+# objects to test
+from bsie.matcher.default_matcher import DefaultMatcher
+
+
+## code ##
+
+@dataclass(kw_only=True, unsafe_hash=True)
+class Invalid(nodes.Node):
+    ucid: str
+
+class TestDefaultMatcher(unittest.TestCase):
+
+    def test_match_node(self):
+        # setup
+        matcher = DefaultMatcher('http://example.com', 'me')
+        # match_node doesn't modify existing uris
+        self.assertEqual(matcher.match_node(
+            nodes.Node(uri='http://example.com/you/foo#bar')).uri,
+            URI('http://example.com/you/foo#bar'))
+        # processes bsn:Entity
+        self.assertEqual(matcher.match_node(
+            nodes.Entity(ucid='abc123cba')).uri,
+            URI('http://example.com/me/file#abc123cba'))
+        # processes bsn:Preview
+        self.assertEqual(matcher.match_node(
+            nodes.Preview(ucid='abc123cba', size=123)).uri,
+            URI('http://example.com/me/preview#abc123cba_s123'))
+        # processes bsn:Tag
+        self.assertEqual(matcher.match_node(
+            nodes.Tag(label='hello')).uri,
+            URI('http://example.com/me/tag#hello'))
+        # processes bsn:Face
+        self.assertEqual(matcher.match_node(
+            nodes.Face(ucid='hello')).uri,
+            URI('http://example.com/me/face#hello'))
+        # raises an exception on unknown types
+        self.assertRaises(ValueError, matcher.match_node,
+            Invalid(ucid='abc123cba'))
+
+    def test_match_entity(self):
+        # setup
+        matcher = DefaultMatcher('http://example.com', 'me')
+        # match_entity uses ucid
+        self.assertEqual(matcher.match_entity(
+            nodes.Entity(ucid='123abc321')).uri,
+            URI('http://example.com/me/file#123abc321'))
+
+    def test_match_preview(self):
+        # setup
+        matcher = DefaultMatcher('http://example.com', 'me')
+        # match_preview uses ucid
+        self.assertEqual(matcher.match_preview(
+            nodes.Preview(ucid='123abc321', size=400)).uri,
+            URI('http://example.com/me/preview#123abc321_s400'))
+        self.assertEqual(matcher.match_preview(
+            nodes.Preview(ucid='321cba123', size=200)).uri,
+            URI('http://example.com/me/preview#321cba123_s200'))
+
+    def test_match_tag(self):
+        # setup
+        matcher = DefaultMatcher('http://example.com', 'me')
+        # match_tag uses label
+        self.assertEqual(matcher.match_tag(
+            nodes.Tag(label='hello')).uri,
+            URI('http://example.com/me/tag#hello'))
+        # match_tag matches the label
+        self.assertEqual(
+            matcher.match_tag(nodes.Tag(label='world')),
+            matcher.match_tag(nodes.Tag(label='world')),
+            )
+        self.assertNotEqual(
+            matcher.match_tag(nodes.Tag(label='hello')),
+            matcher.match_tag(nodes.Tag(label='world')),
+            )
+        # label can include characters that are not valid for an uri
+        self.assertEqual(matcher.match_tag(
+            nodes.Tag(label='hello world { foo bar ] ')).uri,
+            URI('http://example.com/me/tag#hello%20world%20%7B%20foo%20bar%20%5D%20'))
+
+    def test_match_face(self):
+        # setup
+        matcher = DefaultMatcher('http://example.com', 'me')
+        # match_face uses ucid
+        self.assertEqual(matcher.match_face(
+            nodes.Face(ucid='hello_world')).uri,
+            URI('http://example.com/me/face#hello_world'))
+
+
+## main ##
+
+if __name__ == '__main__':
+    unittest.main()
+
+## EOF ##
diff --git a/test/matcher/test_matcher.py b/test/matcher/test_matcher.py
new file mode 100644
index 0000000..eaa4766
--- /dev/null
+++ b/test/matcher/test_matcher.py
@@ -0,0 +1,62 @@
+
+# standard imports
+import unittest
+
+# bsie imports
+from bsie.matcher import nodes
+from bsie.utils import ns, errors
+from bsie.utils.bsfs import URI
+
+# objects to test
+from bsie.matcher.matcher import Matcher, MatcherIterator
+
+
+## code ##
+
+class StubMatcher(Matcher):
+    def match_node(self, node):
+        if node.uri is None:
+            node.uri = 'foo'
+        return node
+
+class TestMatcherIterator(unittest.TestCase):
+
+    def test_call(self):
+        # setup
+        matcher = StubMatcher()
+        # call accepts list
+        triples = [('node', 'pred', 'value'), ('node', 'pred', 'value')]
+        it = matcher(triples)
+        self.assertIsInstance(it, MatcherIterator)
+        self.assertEqual(it._iterable, triples)
+        self.assertEqual(it._matcher, matcher)
+        # call accepts iterator
+        triples = iter([('node', 'pred', 'value'), ('node', 'pred', 'value')])
+        it = matcher(triples)
+        self.assertIsInstance(it, MatcherIterator)
+        self.assertEqual(it._iterable, triples)
+        self.assertEqual(it._matcher, matcher)
+
+    def test_iter(self):
+        # setup
+        matcher = StubMatcher()
+        triples = [
+            (nodes.Entity(ucid='foo'), 'predA', 'hello'),
+            (nodes.Preview(ucid='bar', size=123), 'predB', 1234),
+            (nodes.Preview(ucid='hello', size=321), 'predC', nodes.Entity(ucid='world'))
+            ]
+        # handles nodes, handles values, ignores predicate
+        self.assertListEqual(list(matcher(triples)), [
+            (nodes.Entity(uri='foo', ucid='foo'), 'predA', 'hello'),
+            (nodes.Preview(uri='foo', ucid='bar', size=123), 'predB', 1234),
+            (nodes.Preview(uri='foo', ucid='hello', size=321), 'predC',
+                nodes.Entity(uri='foo', ucid='world')),
+            ])
+
+
+## main ##
+
+if __name__ == '__main__':
+    unittest.main()
+
+## EOF ##
diff --git a/test/matcher/test_nodes.py b/test/matcher/test_nodes.py
new file mode 100644
index 0000000..d884132
--- /dev/null
+++ b/test/matcher/test_nodes.py
@@ -0,0 +1,96 @@
+
+# standard imports
+import unittest
+
+# bsie imports
+from bsie.utils import bsfs, ns
+
+# objects to test
+from bsie.matcher import nodes
+
+
+## code ##
+
+class TestNode(unittest.TestCase):
+    def test_node(self):
+        # cannot pass additional kwargs
+        self.assertRaises(TypeError, nodes.Node, foo='bar')
+        # may pass uri
+        self.assertIsInstance(nodes.Node(uri='bar'), nodes.Node)
+        self.assertEqual(nodes.Node(uri='bar').uri, 'bar')
+
+    def test_entity(self):
+        # must pass ucid
+        self.assertRaises(TypeError, nodes.Entity)
+        self.assertRaises(TypeError, nodes.Entity, uri='foo')
+        self.assertIsInstance(nodes.Entity(ucid='foo'), nodes.Entity)
+        self.assertIsInstance(nodes.Entity(ucid='bar'), nodes.Entity)
+        # cannot pass additional kwargs
+        self.assertRaises(TypeError, nodes.Entity, ucid='foo', foo='bar')
+        # may pass uri
+        self.assertIsInstance(nodes.Entity(ucid='foo', uri='bar'), nodes.Entity)
+        self.assertEqual(nodes.Entity(ucid='foo', uri='bar').uri, 'bar')
+        # has node_type
+        self.assertEqual(nodes.Entity(ucid='foo').node_type, ns.bsn.Entity)
+
+    def test_face(self):
+        # must pass ucid
+        self.assertRaises(TypeError, nodes.Face)
+        self.assertRaises(TypeError, nodes.Face, uri='foo')
+        self.assertIsInstance(nodes.Face(ucid='foo'), nodes.Face)
+        self.assertIsInstance(nodes.Face(ucid='bar'), nodes.Face)
+        # cannot pass additional kwargs
+        self.assertRaises(TypeError, nodes.Face, ucid='foo', foo='bar')
+        # may pass uri
+        self.assertIsInstance(nodes.Face(ucid='foo', uri='bar'), nodes.Face)
+        self.assertEqual(nodes.Face(ucid='foo', uri='bar').uri, 'bar')
+        # has node_type
+        self.assertEqual(nodes.Face(ucid='foo').node_type, ns.bsn.Face)
+
+    def test_person(self):
+        # cannot pass additional kwargs
+        self.assertRaises(TypeError, nodes.Person, foo='bar')
+        # may pass uri
+        self.assertIsInstance(nodes.Person(uri='bar'), nodes.Person)
+        self.assertEqual(nodes.Person(uri='bar').uri, 'bar')
+        # has node_type
+        self.assertEqual(nodes.Person().node_type, ns.bsn.Person)
+
+    def test_preview(self):
+        # must pass ucid and size
+        self.assertRaises(TypeError, nodes.Preview)
+        self.assertRaises(TypeError, nodes.Preview, ucid='foo')
+        self.assertRaises(TypeError, nodes.Preview, size=123)
+        self.assertRaises(TypeError, nodes.Preview, ucid='foo', uri='foo')
+        self.assertRaises(TypeError, nodes.Preview, size=123, uri='foo')
+        self.assertIsInstance(nodes.Preview(ucid='foo', size=123), nodes.Preview)
+        self.assertIsInstance(nodes.Preview(ucid='bar', size=321), nodes.Preview)
+        # cannot pass additional kwargs
+        self.assertRaises(TypeError, nodes.Preview, ucid='foo', size=123, foo='bar')
+        # may pass uri
+        self.assertIsInstance(nodes.Preview(ucid='foo', size=123, uri='bar'), nodes.Preview)
+        self.assertEqual(nodes.Preview(ucid='foo', size=123, uri='bar').uri, 'bar')
+        # has node_type
+        self.assertEqual(nodes.Preview(ucid='foo', size=123).node_type, ns.bsn.Preview)
+
+    def test_tag(self):
+        # must pass label
+        self.assertRaises(TypeError, nodes.Tag)
+        self.assertRaises(TypeError, nodes.Tag, uri='foo')
+        self.assertIsInstance(nodes.Tag(label='foo'), nodes.Tag)
+        self.assertIsInstance(nodes.Tag(label='bar'), nodes.Tag)
+        # cannot pass additional kwargs
+        self.assertRaises(TypeError, nodes.Tag, label='foo', foo='bar')
+        # may pass uri
+        self.assertIsInstance(nodes.Tag(label='foo', uri='bar'), nodes.Tag)
+        self.assertEqual(nodes.Tag(label='foo', uri='bar').uri, 'bar')
+        # has node_type
+        self.assertEqual(nodes.Tag(label='foo').node_type, ns.bsn.Tag)
+
+
+## main ##
+
+if __name__ == '__main__':
+    unittest.main()
+
+## EOF ##
diff --git a/test/utils/test_node.py b/test/utils/test_node.py
deleted file mode 100644
index c0662a1..0000000
--- a/test/utils/test_node.py
+++ /dev/null
@@ -1,92 +0,0 @@
-
-# standard imports
-import unittest
-
-# bsie imports
-from bsie.utils import bsfs, ns
-
-# objects to test
-from bsie.utils.node import Node
-
-
-## code ##
-
-class TestNode(unittest.TestCase):
-    def test_equality(self):
-        uri1 = bsfs.URI('http://example.com/me/entity#1234')
-        uri2 = bsfs.URI('http://example.com/me/entity#4321')
-        node = Node(ns.bsfs.Entity, uri1)
-        # equality respects uri
-        self.assertEqual(node, Node(ns.bsfs.Entity, uri1))
-        self.assertEqual(hash(node), hash(Node(ns.bsfs.Entity, uri1)))
-        self.assertNotEqual(node, Node(ns.bsfs.Entity, uri2))
-        self.assertNotEqual(hash(node), hash(Node(ns.bsfs.Entity, uri2)))
-        # equality respects hints
-        self.assertEqual(
-            Node(ns.bsfs.Entity, foo='foo'),
-            Node(ns.bsfs.Entity, foo='foo'))
-        self.assertEqual(
-            hash(Node(ns.bsfs.Entity, foo='foo')),
-            hash(Node(ns.bsfs.Entity, foo='foo')))
-        self.assertNotEqual(
-            Node(ns.bsfs.Entity, foo='foo'),
-            Node(ns.bsfs.Entity, foo='bar'))
-        self.assertNotEqual(
-            hash(Node(ns.bsfs.Entity, foo='foo')),
-            hash(Node(ns.bsfs.Entity, foo='bar')))
-        self.assertNotEqual(
-            Node(ns.bsfs.Entity, foo='bar'),
-            Node(ns.bsfs.Entity, bar='foo'))
-        self.assertNotEqual(
-            hash(Node(ns.bsfs.Entity, foo='bar')),
-            hash(Node(ns.bsfs.Entity, bar='foo')))
-        # hints are irrelevant if uri is set
-        self.assertEqual(
-            Node(ns.bsfs.Entity, uri=uri1, foo='bar'),
-            Node(ns.bsfs.Entity, uri=uri1, bar='foo'))
-        self.assertEqual(
-            hash(Node(ns.bsfs.Entity, uri=uri1, foo='bar')),
-            hash(Node(ns.bsfs.Entity, uri=uri1, bar='foo')))
-        self.assertNotEqual(
-            Node(ns.bsfs.Entity, uri=uri1, foo='bar'),
-            Node(ns.bsfs.Entity, uri=uri2, bar='foo'))
-        self.assertNotEqual(
-            hash(Node(ns.bsfs.Entity, uri=uri1, foo='bar')),
-            hash(Node(ns.bsfs.Entity, uri=uri2, bar='foo')))
-        # equality respects node_type
-        self.assertNotEqual(node, Node(ns.bsfs.Foo, uri1))
-        self.assertNotEqual(hash(node), hash(Node(ns.bsfs.Foo, uri1)))
-        # not equal to other types
-        self.assertNotEqual(node, 1234)
-        self.assertNotEqual(hash(node), hash(1234))
-        self.assertNotEqual(node, uri1)
-        self.assertNotEqual(hash(node), hash(uri1))
-        self.assertNotEqual(node, ns.bsfs.Entity)
-        self.assertNotEqual(hash(node), hash(ns.bsfs.Entity))
-        class Foo(): pass
-        self.assertNotEqual(node, Foo())
-        self.assertNotEqual(hash(node), hash(Foo()))
-
-    def test_str(self):
-        uri = bsfs.URI('http://example.com/me/entity#1234')
-        # basic string conversion
-        node = Node(ns.bsn.Entity, uri)
-        self.assertEqual(str(node), 'Node(https://schema.bsfs.io/ie/Node/Entity, http://example.com/me/entity#1234)')
-        self.assertEqual(repr(node), 'Node(https://schema.bsfs.io/ie/Node/Entity, http://example.com/me/entity#1234)')
-        # string conversion respects node_type
-        node = Node(ns.bsn.Foo, uri)
-        self.assertEqual(str(node), 'Node(https://schema.bsfs.io/ie/Node/Foo, http://example.com/me/entity#1234)')
-        self.assertEqual(repr(node), 'Node(https://schema.bsfs.io/ie/Node/Foo, http://example.com/me/entity#1234)')
-        # string conversion respects uri
-        node = Node(ns.bsn.Entity, bsfs.URI('http://example.com/me/entity#4321'))
-        self.assertEqual(str(node), 'Node(https://schema.bsfs.io/ie/Node/Entity, http://example.com/me/entity#4321)')
-        self.assertEqual(repr(node), 'Node(https://schema.bsfs.io/ie/Node/Entity, http://example.com/me/entity#4321)')
-
-
-
-## main ##
-
-if __name__ == '__main__':
-    unittest.main()
-
-## EOF ##