reorganizing the code

Signed-off-by: Leonardo de Moura <leonardo@microsoft.com>

src/ast/normal_forms/nnf.h

@@ -0,0 +1,54 @@
+/*++
+Copyright (c) 2007 Microsoft Corporation
+
+Module Name:
+
+    nnf.h
+
+Abstract:
+
+    Negation Normal Form & Skolemization
+
+Author:
+
+    Leonardo (leonardo) 2008-01-11
+
+Notes:
+    Major revision on 2011-10-06
+
+--*/
+#ifndef _NNF_H_
+#define _NNF_H_
+
+#include"ast.h"
+#include"nnf_params.h"
+#include"params.h"
+#include"defined_names.h"
+
+class nnf {
+    struct imp;
+    imp *  m_imp;
+public:
+    nnf(ast_manager & m, defined_names & n, params_ref const & p = params_ref());
+    nnf(ast_manager & m, defined_names & n, nnf_params & params); // for backward compatibility
+    ~nnf();
+    
+    void operator()(expr * n,                          // [IN] expression that should be put into NNF
+                    expr_ref_vector & new_defs,        // [OUT] new definitions
+                    proof_ref_vector & new_def_proofs, // [OUT] proofs of the new definitions 
+                    expr_ref & r,                      // [OUT] resultant expression
+                    proof_ref & p                      // [OUT] proof for (~ n r)
+                    );
+
+    void updt_params(params_ref const & p);
+    static void get_param_descrs(param_descrs & r);
+
+    void cancel() { set_cancel(true); }
+    void reset_cancel() { set_cancel(false); }
+    void set_cancel(bool f);
+
+    void reset();
+    void reset_cache();
+};
+
+#endif /* _NNF_H_ */