adding maxlex, throttle use of asymmetric literal addition

Signed-off-by: Nikolaj Bjorner <nbjorner@microsoft.com>

src/opt/maxlex.h

@@ -0,0 +1,32 @@
+/*++
+Copyright (c) 2014 Microsoft Corporation
+
+Module Name:
+
+    maxlex.h
+
+Abstract:
+   
+    MaxLex solves weighted max-sat problems where weights impose lexicographic order.
+
+Author:
+
+    Nikolaj Bjorner (nbjorner) 2019-25-1
+
+Notes:
+
+--*/
+
+#ifndef MAXLEX_H_
+#define MAXLEX_H_
+
+namespace opt {
+
+    bool is_maxlex(weights_t & ws);
+
+    maxsmt_solver_base* mk_maxlex(maxsat_context& c, unsigned id, weights_t & ws, expr_ref_vector const& soft);
+
+
+};
+
+#endif