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+/*********************                                                        */
+/*! \file proof_to_sexpr.h
+ ** \verbatim
+ ** Top contributors (to current version):
+ **   Andrew Reynolds
+ ** This file is part of the CVC4 project.
+ ** Copyright (c) 2009-2019 by the authors listed in the file AUTHORS
+ ** in the top-level source directory) and their institutional affiliations.
+ ** All rights reserved.  See the file COPYING in the top-level source
+ ** directory for licensing information.\endverbatim
+ **
+ ** \brief Conversion from ProofNode to s-expressions
+ **/
+
+#include "cvc4_private.h"
+
+#ifndef CVC4__EXPR__PROOF_NODE_TO_SEXPR_H
+#define CVC4__EXPR__PROOF_NODE_TO_SEXPR_H
+
+#include <map>
+
+#include "expr/node.h"
+#include "expr/proof_node.h"
+
+namespace CVC4 {
+
+/** A class to convert ProofNode objects to s-expressions */
+class ProofNodeToSExpr
+{
+ public:
+  ProofNodeToSExpr();
+  ~ProofNodeToSExpr() {}
+  /** Convert the given proof node to an s-expression
+   *
+   * This is useful for operations where it is useful to view a ProofNode as
+   * a Node. Printing is one such example, where a ProofNode can be printed
+   * as a dag after this conversion.
+   *
+   * The s-expression for a ProofNode has the form:
+   *   (SEXPR (VAR "<d_rule>") S1 ... Sn (VAR ":args") (SEXPR <d_args>))
+   * where S1, ..., Sn are the s-expressions for its <d_children>.
+   */
+  Node convertToSExpr(const ProofNode* pn);
+
+ private:
+  /** map proof rules to a variable */
+  std::map<PfRule, Node> d_pfrMap;
+  /** Dummy ":args" marker */
+  Node d_argsMarker;
+  /** map proof nodes to their s-expression */
+  std::map<const ProofNode*, Node> d_pnMap;
+  /**
+   * map nodes to a bound variable, used for nodes that have special AST status
+   * like builtin operators
+   */
+  std::map<Node, Node> d_nodeMap;
+  /** get or make pf rule variable */
+  Node getOrMkPfRuleVariable(PfRule r);
+  /** get or make node variable */
+  Node getOrMkNodeVariable(Node n);
+};
+
+}  // namespace CVC4
+
+#endif /* CVC4__EXPR__PROOF_RULE_H */