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       1                 :            : /******************************************************************************
       2                 :            :  * Top contributors (to current version):
       3                 :            :  *   Andrew Reynolds, Hans-Joerg Schurr, Gereon Kremer
       4                 :            :  *
       5                 :            :  * This file is part of the cvc5 project.
       6                 :            :  *
       7                 :            :  * Copyright (c) 2009-2025 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                 :            :  * Proof step and proof step buffer utilities.
      14                 :            :  */
      15                 :            : 
      16                 :            : #include "cvc5_private.h"
      17                 :            : 
      18                 :            : #ifndef CVC5__PROOF__PROOF_STEP_BUFFER_H
      19                 :            : #define CVC5__PROOF__PROOF_STEP_BUFFER_H
      20                 :            : 
      21                 :            : #include <vector>
      22                 :            : 
      23                 :            : #include "cvc5/cvc5_proof_rule.h"
      24                 :            : #include "expr/node.h"
      25                 :            : #include "proof/trust_id.h"
      26                 :            : 
      27                 :            : namespace cvc5::internal {
      28                 :            : 
      29                 :            : class ProofChecker;
      30                 :            : 
      31                 :            : /**
      32                 :            :  * Information for constructing a step in a CDProof. Notice that the conclusion
      33                 :            :  * of the proof step is intentionally not included in this data structure.
      34                 :            :  * Instead, it is intended that conclusions may be associated with proof steps
      35                 :            :  * based on e.g. the result of proof checking.
      36                 :            :  */
      37                 :            : class ProofStep
      38                 :            : {
      39                 :            :  public:
      40                 :            :   ProofStep();
      41                 :            :   ProofStep(ProofRule r,
      42                 :            :             const std::vector<Node>& children,
      43                 :            :             const std::vector<Node>& args);
      44                 :            :   /** The proof rule */
      45                 :            :   ProofRule d_rule;
      46                 :            :   /** The proof children */
      47                 :            :   std::vector<Node> d_children;
      48                 :            :   /** The proof arguments */
      49                 :            :   std::vector<Node> d_args;
      50                 :            : };
      51                 :            : std::ostream& operator<<(std::ostream& out, ProofStep step);
      52                 :            : 
      53                 :            : /**
      54                 :            :  * Class used to speculatively try and buffer a set of proof steps before
      55                 :            :  * sending them to a proof object.
      56                 :            :  */
      57                 :            : class ProofStepBuffer
      58                 :            : {
      59                 :            :  public:
      60                 :            :   /**
      61                 :            :    * @param pc The proof checker we are using
      62                 :            :    * @param ensureUnique Whether we ensure that the conclusions of steps
      63                 :            :    * added to this buffer are unique. Later steps with the same conclusion as
      64                 :            :    * a previous one are discarded.
      65                 :            :    * @param autoSym Whether this proof step buffer is considering symmetry
      66                 :            :    * automatically. For example, this should be true if the steps of this buffer
      67                 :            :    * are being added to a CDProof with automatic symmetry. This impacts
      68                 :            :    * uniqueness of conclusions and whether certain steps are necessary.
      69                 :            :    */
      70                 :            :   ProofStepBuffer(ProofChecker* pc = nullptr,
      71                 :            :                   bool ensureUnique = false,
      72                 :            :                   bool autoSym = true);
      73                 :    4111200 :   ~ProofStepBuffer() {}
      74                 :            :   /**
      75                 :            :    * Returns the conclusion of the proof step, as determined by the proof
      76                 :            :    * checker of the given proof. If this is non-null, then the given step
      77                 :            :    * is added to the buffer maintained by this class.
      78                 :            :    *
      79                 :            :    * If expected is non-null, then this method returns null if the result of
      80                 :            :    * checking is not equal to expected. Furthermore note that if proof
      81                 :            :    * checking is set to none, this method will always successfully return
      82                 :            :    * expected.
      83                 :            :    */
      84                 :            :   Node tryStep(ProofRule id,
      85                 :            :                const std::vector<Node>& children,
      86                 :            :                const std::vector<Node>& args,
      87                 :            :                Node expected = Node::null());
      88                 :            :   /** Same as try step, but tracks whether a step was added */
      89                 :            :   Node tryStep(bool& added,
      90                 :            :                ProofRule id,
      91                 :            :                const std::vector<Node>& children,
      92                 :            :                const std::vector<Node>& args,
      93                 :            :                Node expected = Node::null());
      94                 :            :   /**
      95                 :            :    * Same as above, without checking
      96                 :            :    * @return true if a step was added. This may return false if e.g. expected
      97                 :            :    * was a duplicate conclusion.
      98                 :            :    */
      99                 :            :   bool addStep(ProofRule id,
     100                 :            :                const std::vector<Node>& children,
     101                 :            :                const std::vector<Node>& args,
     102                 :            :                Node expected);
     103                 :            :   /** Add trusted step */
     104                 :            :   bool addTrustedStep(TrustId id,
     105                 :            :                       const std::vector<Node>& children,
     106                 :            :                       const std::vector<Node>& args,
     107                 :            :                       Node conc);
     108                 :            :   /** Multi-step version */
     109                 :            :   void addSteps(ProofStepBuffer& psb);
     110                 :            :   /** pop step */
     111                 :            :   void popStep();
     112                 :            :   /** Get num steps */
     113                 :            :   size_t getNumSteps() const;
     114                 :            :   /** Get steps */
     115                 :            :   const std::vector<std::pair<Node, ProofStep>>& getSteps() const;
     116                 :            :   /** Clear */
     117                 :            :   void clear();
     118                 :            : 
     119                 :            :  protected:
     120                 :            :   /**
     121                 :            :    * Whether this proof step buffer is being added to a CDProof with automatic
     122                 :            :    * symmetry. This impacts uniqueness of conclusions and whether certain
     123                 :            :    * steps are necessary.
     124                 :            :    */
     125                 :            :   bool d_autoSym;
     126                 :            : 
     127                 :            :  private:
     128                 :            :   /** The proof checker*/
     129                 :            :   ProofChecker* d_checker;
     130                 :            :   /** the queued proof steps */
     131                 :            :   std::vector<std::pair<Node, ProofStep>> d_steps;
     132                 :            :   /** Whether we are ensuring the conclusions in the buffer are unique */
     133                 :            :   bool d_ensureUnique;
     134                 :            :   /** The set of conclusions in steps */
     135                 :            :   std::unordered_set<Node> d_allSteps;
     136                 :            : };
     137                 :            : 
     138                 :            : }  // namespace cvc5::internal
     139                 :            : 
     140                 :            : #endif /* CVC5__PROOF__PROOF_STEP_BUFFER_H */