From 1cfcfda8c4fa240ced782bb061f61b81c30e1410 Mon Sep 17 00:00:00 2001
From: Gunnar Aastrand Grimnes <gromgull@gmail.com>
Date: Mon, 30 Dec 2013 17:16:26 +0100
Subject: [PATCH] added test and fixed #312

---
 rdflib/plugins/parsers/notation3.py |  7 +++++--
 test/test_n3.py                     | 11 +++++++++++
 2 files changed, 16 insertions(+), 2 deletions(-)

diff --git a/rdflib/plugins/parsers/notation3.py b/rdflib/plugins/parsers/notation3.py
index caa75b019..fb61b04af 100644
--- a/rdflib/plugins/parsers/notation3.py
+++ b/rdflib/plugins/parsers/notation3.py
@@ -1165,8 +1165,11 @@ def uri_ref2(self, argstr, i, res):
                     if pfx == "_":  # Magic prefix 2001/05/30, can be changed
                         res.append(self.anonymousNode(ln))
                         return j
-                    self.BadSyntax(argstr, i,
-                        "Prefix \"%s:\" not bound" % (pfx))
+                    if not self.turtle and pfx == "":
+                        ns = join(self._baseURI or "", "#")
+                    else:
+                        self.BadSyntax(argstr, i,
+                                       "Prefix \"%s:\" not bound" % (pfx))
             symb = self._store.newSymbol(ns + ln)
             if symb in self._variables:
                 res.append(self._variables[symb])
diff --git a/test/test_n3.py b/test/test_n3.py
index d6fc1f2d8..3255df254 100644
--- a/test/test_n3.py
+++ b/test/test_n3.py
@@ -218,5 +218,16 @@ def testSingleQuotedLiterals(self):
             for _, _, o in g:
                 self.assertEqual(o, Literal('o'))
 
+    def testEmptyPrefix(self):
+
+        # this is issue https://github.com/RDFLib/rdflib/issues/312
+        g1 = Graph()
+        g1.parse(data = ":a :b :c .", format='n3')
+
+        g2 = Graph()
+        g2.parse(data = "@prefix : <#> . :a :b :c .", format='n3')
+
+        assert set(g1) == set(g2), 'Document with declared empty prefix must match default #'
+
 if __name__ == '__main__':
     unittest.main()