separate out, add copy constructor

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

src/ast/justified_expr.h

@@ -0,0 +1,52 @@
+
+#ifndef JUSTIFIED_EXPR_H_
+#define JUSTIFIED_EXPR_H_
+
+#include "ast/ast.h"
+
+class justified_expr {
+    ast_manager& m;
+    expr*        m_fml;
+    proof*       m_proof;
+public:
+    justified_expr(ast_manager& m, expr* fml, proof* p):
+        m(m),
+        m_fml(fml),
+        m_proof(p) {
+        SASSERT(fml);
+        m.inc_ref(fml);
+        m.inc_ref(p);
+    }
+    
+    justified_expr& operator=(justified_expr const& other) {
+        SASSERT(&m == &other.m);
+        if (this != &other) {
+            m.dec_ref(m_fml);
+            m.dec_ref(m_proof);
+            m_fml = other.get_fml();
+            m_proof = other.get_proof();
+            m.inc_ref(m_fml);
+            m.inc_ref(m_proof);
+        }
+        return *this;
+    }
+    
+    justified_expr(justified_expr const& other):
+        m(other.m),
+        m_fml(other.m_fml),
+        m_proof(other.m_proof)
+    {
+        m.inc_ref(m_fml);
+        m.inc_ref(m_proof);
+    }
+
+    ~justified_expr() {
+        m.dec_ref(m_fml);
+        m.dec_ref(m_proof);
+    }
+    
+    expr* get_fml() const { return m_fml; }
+    proof* get_proof() const { return m_proof; }        
+};
+
+#endif