1 files changed, 54 insertions, 0 deletions
diff --git a/tools/rdf.py b/tools/rdf.py
new file mode 100644
index 0000000..6aaa682
--- /dev/null
+++ b/tools/rdf.py
@@ -0,0 +1,54 @@
+from rdflib.namespace import RDF, NamespaceManager
+
+class RDFWalker:
+    """
+    Simple RDF graph walker
+    """
+
+    def __init__ (self, g, s, n, path=[]):
+        """
+        :param g: Graph
+        :param s: Namespace
+        :param n: Start node
+        """
+        self.g = g
+        self.n = n
+        self.s = s
+        self._path = path
+
+    def __getattr__ (self, k):
+        """
+        If k is underscore _, walk up tree one level, otherwise search for
+        direct descendents and get first one.
+        """
+        if k == '_':
+            return RDFWalker (self.g, self.s, self._path[0], self._path[1:])
+        yieldall = False
+        if k.endswith ('_'):
+            yieldall = True
+            k = k[:-1]
+
+        if k == 'a':
+            attr = RDF.type
+        else:
+            attr = getattr (self.s, k)
+
+        ret = [RDFWalker (self.g, self.s, n, [self.n] + self._path) for n in self.g.objects (self.n, attr)]
+
+        if yieldall:
+            return ret
+        elif not ret:
+            return None
+        else:
+            return ret[0]
+
+    def __eq__ (self, b):
+        return self.n == b.n
+
+    def __lt__ (self, b):
+        return str (self) < str (b)
+
+    def __str__ (self):
+        return str (self.n)
+
+