Merge branch 'previews' into develop

2 files changed, 26 insertions, 7 deletions

diff --git a/bsie/utils/namespaces.py b/bsie/utils/namespaces.py
index 393b436..0af8ece 100644
--- a/bsie/utils/namespaces.py
+++ b/bsie/utils/namespaces.py
@@ -12,16 +12,18 @@ from . import bsfs as _bsfs
 
 # constants
 bse = _bsfs.Namespace('http://bsfs.ai/schema/Entity')
+bsf = _bsfs.Namespace('http://ie.bsfs.ai/schema/Feature')
 bsfs = _bsfs.Namespace('http://bsfs.ai/schema', fsep='/')
 bsm = _bsfs.Namespace('http://bsfs.ai/schema/Meta')
+bsp = _bsfs.Namespace('http://bsfs.ai/schema/Preview')
 xsd = _bsfs.Namespace('http://www.w3.org/2001/XMLSchema')
-bsf = _bsfs.Namespace('http://ie.bsfs.ai/schema/Feature')
 
 # export
 __all__: typing.Sequence[str] = (
     'bse',
     'bsfs',
     'bsm',
+    'bsp',
     'xsd',
     )
 
diff --git a/bsie/utils/node.py b/bsie/utils/node.py
index 91e4f37..aa62c06 100644
--- a/bsie/utils/node.py
+++ b/bsie/utils/node.py
@@ -19,30 +19,47 @@ __all__: typing.Sequence[str] = (
 ## code ##
 
 class Node():
-    """Lightweight Node, disconnected from any bsfs structures."""
+    """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: bsfs.URI
+    uri: typing.Optional[bsfs.URI]
+
+    # node naming hints.
+    hits: dict
 
     def __init__(
             self,
             node_type: bsfs.URI,
-            uri: bsfs.URI,
+            uri: typing.Optional[bsfs.URI] = None,
+            **uri_hints,
             ):
         # assign members
         self.node_type = bsfs.URI(node_type)
-        self.uri = bsfs.URI(uri)
+        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 other.uri == self.uri \
+            and (self.uri is not None or self.hints == other.hints)
 
     def __hash__(self) -> int:
-        return hash((type(self), self.node_type, self.uri))
+        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})'