wbemprox: Support NULL tests that use equality operators.

dlls/wbemprox/tests/query.c

@@ -106,8 +106,14 @@ static void test_select( IWbemServices *services )
         {'S','E','L','E','C','T',' ','*',' ','F','R','O','M',' ',
          'W','i','n','3','2','_','V','i','d','e','o','C','o','n','t','r','o','l','l','e','r',' ','w','h','e','r','e',' ',
          'a','v','a','i','l','a','b','i','l','i','t','y',' ','=',' ','\'','3','\'',0};
+    static const WCHAR query12[] =
+        {'S','E','L','E','C','T',' ','*',' ','F','R','O','M',' ','W','i','n','3','2','_','B','I','O','S',
+         ' ','W','H','E','R','E',' ','N','A','M','E',' ','<','>',' ','N','U','L','L', 0};
+    static const WCHAR query13[] =
+        {'S','E','L','E','C','T',' ','*',' ','F','R','O','M',' ','W','i','n','3','2','_','B','I','O','S',
+         ' ','W','H','E','R','E',' ','N','U','L','L',' ','=',' ','N','A','M','E', 0};
     static const WCHAR *test[] = { query1, query2, query3, query4, query5, query6, query7, query8, query9, query10,
-                                   query11 };
+                                   query11, query12, query13 };
     HRESULT hr;
     IEnumWbemClassObject *result;
     BSTR wql = SysAllocString( wqlW );

dlls/wbemprox/wql.y

@@ -414,6 +414,30 @@ expr:
             if (!$$)
                 YYABORT;
         }
+  | prop_val TK_EQ TK_NULL
+        {
+            $$ = expr_unary( ctx, $1, OP_ISNULL );
+            if (!$$)
+                YYABORT;
+        }
+  | TK_NULL TK_EQ prop_val
+        {
+            $$ = expr_unary( ctx, $3, OP_ISNULL );
+            if (!$$)
+                YYABORT;
+        }
+  | prop_val TK_NE TK_NULL
+        {
+            $$ = expr_unary( ctx, $1, OP_NOTNULL );
+            if (!$$)
+                YYABORT;
+        }
+  | TK_NULL TK_NE prop_val
+        {
+            $$ = expr_unary( ctx, $3, OP_NOTNULL );
+            if (!$$)
+                YYABORT;
+        }
     ;
 
 string_val: