Use parameter for unary operator

Closes #93

Author: cedk

CHANGELOG

@@ -1,3 +1,4 @@
+* Use parameter for unary operator
 * Support default values when inserting not matched merge
 * Replace assert by ValueError
 

sql/operators.py

@@ -121,7 +121,8 @@ def _operands(self):
         return self
 
     def __str__(self):
-        return '(' + (' %s ' % self._operator).join(map(str, self)) + ')'
+        return '(' + (' %s ' % self._operator).join(
+            map(self._format, self)) + ')'
 
 
 class And(NaryOperator):

sql/tests/test_operators.py

@@ -32,6 +32,10 @@ def test_and(self):
         self.assertEqual(str(and_), '(%s AND "c2")')
         self.assertEqual(and_.params, (True,))
 
+        and_ = And((Literal(True), 'foo'))
+        self.assertEqual(str(and_), '(%s AND %s)')
+        self.assertEqual(and_.params, (True, 'foo'))
+
     def test_operator_operators(self):
         and_ = And((Literal(True), self.table.c1))
         and2 = and_ & And((Literal(True), self.table.c2))