Fix union; expose Graph.copy() and Graph.empty_copy() as cpdef.

lakesuperior/model/rdf/graph.pxd

@@ -23,13 +23,13 @@ cdef class Graph:
         cc.key_compare_ft term_cmp_fn
         cc.key_compare_ft trp_cmp_fn
 
-        Graph copy(self, str uri=*)
-        Graph empty_copy(self, str uri=*)
         void _match_ptn_callback(
             self, pattern, Graph gr, lookup_callback_fn_t callback_fn,
             bint callback_cond=*, void* ctx=*
         ) except *
 
+    cpdef Graph copy(self, str uri=*)
+    cpdef Graph empty_copy(self, str uri=*)
     cpdef void set(self, tuple trp) except *
 
 

lakesuperior/model/rdf/graph.pyx

@@ -216,7 +216,7 @@ cdef class Graph:
 
     def __or__(self, other):
         """ Set-theoretical union. """
-        cdef Graph gr3 = self.copy()
+        cdef Graph gr3 = self.empty_copy()
 
         gr3.keys = kset.merge(self.keys, other.keys)
 
@@ -373,7 +373,7 @@ cdef class Graph:
 
     ## CYTHON-ACCESSIBLE BASIC METHODS ##
 
-    cdef Graph copy(self, str uri=None):
+    cpdef Graph copy(self, str uri=None):
         """
         Create copy of the graph with a different (or no) URI.
 
@@ -384,8 +384,10 @@ cdef class Graph:
 
         new_gr.keys = self.keys.copy()
 
+        return new_gr
+
 
-    cdef Graph empty_copy(self, str uri=None):
+    cpdef Graph empty_copy(self, str uri=None):
         """
         Create an empty copy with same capacity and store binding.
 

lakesuperior/model/structures/keyset.pyx

@@ -154,9 +154,12 @@ cdef class Keyset:
         """
         Copy a Keyset.
         """
-        cdef Keyset new_ks = Keyset(self.capacity, expand_ratio=self.expand_ratio)
+        cdef Keyset new_ks = Keyset(
+            self.capacity, expand_ratio=self.expand_ratio
+        )
         memcpy(new_ks.data, self.data, self.capacity * TRP_KLEN)
         new_ks.seek()
+        new_ks._free_i = self._free_i
 
         return new_ks