Merge pull request #1321 from rchateauneu/speedup_term_hash

Speedup Literal.__hash__ and Literal.__eq__ by accessing directly _da…

rdflib/term.py

@@ -978,10 +978,11 @@ def __hash__(self):
         """
         # don't use super()... for efficiency reasons, see Identifier.__hash__
         res = str.__hash__(self)
-        if self.language:
-            res ^= hash(self.language.lower())
-        if self.datatype:
-            res ^= hash(self.datatype)
+        # Directly accessing the member is faster than the property.
+        if self._language:
+            res ^= hash(self._language.lower())
+        if self._datatype:
+            res ^= hash(self._datatype)
         return res
 
     def __eq__(self, other):
@@ -1024,11 +1025,12 @@ def __eq__(self, other):
             return True
         if other is None:
             return False
+        # Directly accessing the member is faster than the property.
         if isinstance(other, Literal):
             return (
-                self.datatype == other.datatype
-                and (self.language.lower() if self.language else None)
-                == (other.language.lower() if other.language else None)
+                self._datatype == other._datatype
+                and (self._language.lower() if self._language else None)
+                == (other._language.lower() if other._language else None)
                 and str.__eq__(self, other)
             )