split into parts, add stats

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

src/math/polysat/justification.h

@@ -0,0 +1,44 @@
+/*++
+Copyright (c) 2021 Microsoft Corporation
+
+Module Name:
+
+    polysat justification
+
+Author:
+
+    Nikolaj Bjorner (nbjorner) 2021-03-19
+
+--*/
+#pragma once
+#include "math/polysat/types.h"
+
+
+namespace polysat {
+
+
+    /**
+     * Justification kind for a variable assignment.
+     */
+    enum justification_k { unassigned, decision, propagation };
+
+    class justification {
+        justification_k m_kind;
+        unsigned        m_level;
+        justification(justification_k k, unsigned lvl): m_kind(k), m_level(lvl) {}
+    public:
+        justification(): m_kind(justification_k::unassigned) {}
+        static justification unassigned() { return justification(justification_k::unassigned, 0); }
+        static justification decision(unsigned lvl) { return justification(justification_k::decision, lvl); }
+        static justification propagation(unsigned lvl) { return justification(justification_k::propagation, lvl); }
+        bool is_decision() const { return m_kind == justification_k::decision; }
+        bool is_unassigned() const { return m_kind == justification_k::unassigned; }
+        bool is_propagation() const { return m_kind == justification_k::propagation; }
+        justification_k kind() const { return m_kind; }
+        unsigned level() const { return m_level; }
+        std::ostream& display(std::ostream& out) const;
+    };
+
+    inline std::ostream& operator<<(std::ostream& out, justification const& j) { return j.display(out); }
+
+}