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       1                 :            : /******************************************************************************
       2                 :            :  * Top contributors (to current version):
       3                 :            :  *   Andrew Reynolds, Haniel Barbosa
       4                 :            :  *
       5                 :            :  * This file is part of the cvc5 project.
       6                 :            :  *
       7                 :            :  * Copyright (c) 2009-2024 by the authors listed in the file AUTHORS
       8                 :            :  * in the top-level source directory and their institutional affiliations.
       9                 :            :  * All rights reserved.  See the file COPYING in the top-level source
      10                 :            :  * directory for licensing information.
      11                 :            :  * ****************************************************************************
      12                 :            :  *
      13                 :            :  * Node converter utility
      14                 :            :  */
      15                 :            : 
      16                 :            : #include "cvc5_private.h"
      17                 :            : 
      18                 :            : #ifndef CVC5__EXPR__NODE_CONVERTER_H
      19                 :            : #define CVC5__EXPR__NODE_CONVERTER_H
      20                 :            : 
      21                 :            : #include <iostream>
      22                 :            : #include <map>
      23                 :            : 
      24                 :            : #include "expr/node.h"
      25                 :            : #include "expr/type_node.h"
      26                 :            : 
      27                 :            : namespace cvc5::internal {
      28                 :            : 
      29                 :            : /**
      30                 :            :  * A node converter for terms and types. Implements term/type traversals,
      31                 :            :  * calling the provided implementations of conversion methods (pre/postConvert
      32                 :            :  * and pre/postConvertType) at pre-traversal and post-traversal.
      33                 :            :  *
      34                 :            :  * This class can be used as a generic method for converting terms/types, which
      35                 :            :  * is orthogonal to methods for traversing nodes.
      36                 :            :  */
      37                 :            : class NodeConverter
      38                 :            : {
      39                 :            :  public:
      40                 :            :   /**
      41                 :            :    * @param forceIdem If true, this assumes that terms returned by postConvert
      42                 :            :    * and postConvertType should not be converted again.
      43                 :            :    */
      44                 :            :   NodeConverter(NodeManager* nm, bool forceIdem = true);
      45                 :     146937 :   virtual ~NodeConverter() {}
      46                 :            :   /**
      47                 :            :    * This converts node n based on the preConvert/postConvert methods that can
      48                 :            :    * be overriden by instances of this class.
      49                 :            :    *
      50                 :            :    * If n is null, this always returns the null node.
      51                 :            :    *
      52                 :            :    * @param preserveTypes If true, we make calls to postConvert below for the
      53                 :            :    * conversion, which requires that the conversion preserves the types of
      54                 :            :    * all subterms in n. If false, we make calls to postConvertUntyped, which
      55                 :            :    * may change the type of subterms.
      56                 :            :    */
      57                 :            :   Node convert(Node n, bool preserveTypes = true);
      58                 :            : 
      59                 :            :   /**
      60                 :            :    * This converts type node n based on the preConvertType/postConvertType
      61                 :            :    * methods that can be overriden by instances of this class.
      62                 :            :    */
      63                 :            :   TypeNode convertType(TypeNode tn);
      64                 :            : 
      65                 :            :  protected:
      66                 :            :   //------------------------- virtual interface
      67                 :            :   /** Should we traverse n? */
      68                 :            :   virtual bool shouldTraverse(Node n);
      69                 :            :   /**
      70                 :            :    * Run the conversion for n during pre-order traversal.
      71                 :            :    * Returning null is equivalent to saying the node should not be changed.
      72                 :            :    *
      73                 :            :    * If convert is called with preserveTypes=true, then we require that the
      74                 :            :    * type of the returned term (if non-null) is the same as the type of n.
      75                 :            :    */
      76                 :            :   virtual Node preConvert(Node n);
      77                 :            :   /**
      78                 :            :    * Run the conversion for post-order traversal, where notice n is a term
      79                 :            :    * of the form:
      80                 :            :    *   (f i_1 ... i_m)
      81                 :            :    * where i_1, ..., i_m are terms that have been returned by previous calls
      82                 :            :    * to postConvert.
      83                 :            :    *
      84                 :            :    * Returning null is equivalent to saying the node should not be changed.
      85                 :            :    *
      86                 :            :    * We require that the type of the returned term (if non-null) is the same
      87                 :            :    * as the type of n.
      88                 :            :    */
      89                 :            :   virtual Node postConvert(Node n);
      90                 :            :   /**
      91                 :            :    * Run the conversion for post-porder traversal. If orig is of the form
      92                 :            :    * (f e_1 ... e_m), then terms is {i_1, ..., i_m}, where i_1, ..., i_m
      93                 :            :    * is the result of converting e_1, ..., e_m. In contrast to the above
      94                 :            :    * method, the type of the returned term does not need to match the type
      95                 :            :    * of orig. The method also takes whether any of the elements of terms differ
      96                 :            :    * from the children of orig.
      97                 :            :    */
      98                 :            :   virtual Node postConvertUntyped(Node orig,
      99                 :            :                                   const std::vector<Node>& terms,
     100                 :            :                                   bool termsChanged);
     101                 :            :   /**
     102                 :            :    * Run the conversion, same as `preConvert`, but for type nodes, which notice
     103                 :            :    * can be built from children similar to Node.
     104                 :            :    */
     105                 :            :   virtual TypeNode preConvertType(TypeNode n);
     106                 :            :   /**
     107                 :            :    * Run the conversion, same as `postConvert`, but for type nodes, which notice
     108                 :            :    * can be built from children similar to Node.
     109                 :            :    */
     110                 :            :   virtual TypeNode postConvertType(TypeNode n);
     111                 :            :   //------------------------- end virtual interface
     112                 :            :  protected:
     113                 :            :   /** The underlying node manager */
     114                 :            :   NodeManager* d_nm;
     115                 :            : 
     116                 :            :  private:
     117                 :            :   /** Add to cache */
     118                 :            :   void addToCache(TNode cur, TNode ret);
     119                 :            :   /** Add to type cache */
     120                 :            :   void addToTypeCache(TypeNode cur, TypeNode ret);
     121                 :            :   /** Node cache for preConvert */
     122                 :            :   std::unordered_map<Node, Node> d_preCache;
     123                 :            :   /** Node cache for postConvert */
     124                 :            :   std::unordered_map<Node, Node> d_cache;
     125                 :            :   /** TypeNode cache for preConvert */
     126                 :            :   std::unordered_map<TypeNode, TypeNode> d_preTCache;
     127                 :            :   /** TypeNode cache for postConvert */
     128                 :            :   std::unordered_map<TypeNode, TypeNode> d_tcache;
     129                 :            :   /** Whether this node converter is idempotent. */
     130                 :            :   bool d_forceIdem;
     131                 :            : };
     132                 :            : 
     133                 :            : }  // namespace cvc5::internal
     134                 :            : 
     135                 :            : #endif