Merge "Add IS (NOT) DISTINCT FROM operators"

3 files changed, 46 insertions, 2 deletions

diff --git a/lib/sqlalchemy/sql/compiler.py b/lib/sqlalchemy/sql/compiler.py
index 3d2f02006..144f2aa47 100644
--- a/lib/sqlalchemy/sql/compiler.py
+++ b/lib/sqlalchemy/sql/compiler.py
@@ -81,6 +81,8 @@ OPERATORS = {
     operators.gt: ' > ',
     operators.ge: ' >= ',
     operators.eq: ' = ',
+    operators.is_distinct_from: ' IS DISTINCT FROM ',
+    operators.isnot_distinct_from: ' IS NOT DISTINCT FROM ',
     operators.concat_op: ' || ',
     operators.match_op: ' MATCH ',
     operators.notmatch_op: ' NOT MATCH ',
diff --git a/lib/sqlalchemy/sql/default_comparator.py b/lib/sqlalchemy/sql/default_comparator.py
index 1bb1c344c..7630a9821 100644
--- a/lib/sqlalchemy/sql/default_comparator.py
+++ b/lib/sqlalchemy/sql/default_comparator.py
@@ -39,6 +39,12 @@ def _boolean_compare(expr, op, obj, negate=None, reverse=False,
                                     op,
                                     type_=result_type,
                                     negate=negate, modifiers=kwargs)
+        elif op in (operators.is_distinct_from, operators.isnot_distinct_from):
+            return BinaryExpression(expr,
+                                    _literal_as_text(obj),
+                                    op,
+                                    type_=result_type,
+                                    negate=negate, modifiers=kwargs)
         else:
             # all other None/True/False uses IS, IS NOT
             if op in (operators.eq, operators.is_):
@@ -51,8 +57,9 @@ def _boolean_compare(expr, op, obj, negate=None, reverse=False,
                                         negate=operators.is_)
             else:
                 raise exc.ArgumentError(
-                    "Only '=', '!=', 'is_()', 'isnot()' operators can "
-                    "be used with None/True/False")
+                    "Only '=', '!=', 'is_()', 'isnot()', "
+                    "'is_distinct_from()', 'isnot_distinct_from()' "
+                    "operators can be used with None/True/False")
     else:
         obj = _check_literal(expr, op, obj)
 
@@ -249,6 +256,8 @@ operator_lookup = {
     "gt": (_boolean_compare, operators.le),
     "ge": (_boolean_compare, operators.lt),
     "eq": (_boolean_compare, operators.ne),
+    "is_distinct_from": (_boolean_compare, operators.isnot_distinct_from),
+    "isnot_distinct_from": (_boolean_compare, operators.is_distinct_from),
     "like_op": (_boolean_compare, operators.notlike_op),
     "ilike_op": (_boolean_compare, operators.notilike_op),
     "notlike_op": (_boolean_compare, operators.like_op),
diff --git a/lib/sqlalchemy/sql/operators.py b/lib/sqlalchemy/sql/operators.py
index 80f08a97c..bf470710d 100644
--- a/lib/sqlalchemy/sql/operators.py
+++ b/lib/sqlalchemy/sql/operators.py
@@ -311,6 +311,28 @@ class ColumnOperators(Operators):
         """
         return self.operate(ne, other)
 
+    def is_distinct_from(self, other):
+        """Implement the ``IS DISTINCT FROM`` operator.
+
+        Renders "a IS DISTINCT FROM b" on most platforms;
+        on some such as SQLite may render "a IS NOT b".
+
+        .. versionadded:: 1.1
+
+        """
+        return self.operate(is_distinct_from, other)
+
+    def isnot_distinct_from(self, other):
+        """Implement the ``IS NOT DISTINCT FROM`` operator.
+
+        Renders "a IS NOT DISTINCT FROM b" on most platforms;
+        on some such as SQLite may render "a IS b".
+
+        .. versionadded:: 1.1
+
+        """
+        return self.operate(isnot_distinct_from, other)
+
     def __gt__(self, other):
         """Implement the ``>`` operator.
 
@@ -722,6 +744,15 @@ def istrue(a):
 def isfalse(a):
     raise NotImplementedError()
 
+
+def is_distinct_from(a, b):
+    return a.is_distinct_from(b)
+
+
+def isnot_distinct_from(a, b):
+    return a.isnot_distinct_from(b)
+
+
 def is_(a, b):
     return a.is_(b)
 
@@ -931,6 +962,8 @@ _PRECEDENCE = {
 
     eq: 5,
     ne: 5,
+    is_distinct_from: 5,
+    isnot_distinct_from: 5,
     gt: 5,
     lt: 5,
     ge: 5,