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/****************************************************************************** |
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* Top contributors (to current version): |
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* Kshitij Bansal, Andrew Reynolds, Andres Noetzli |
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* |
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* This file is part of the cvc5 project. |
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* |
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* Copyright (c) 2009-2021 by the authors listed in the file AUTHORS |
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* in the top-level source directory and their institutional affiliations. |
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* All rights reserved. See the file COPYING in the top-level source |
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* directory for licensing information. |
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* **************************************************************************** |
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* |
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* Sets theory rewriter. |
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*/ |
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#include "cvc5_private.h" |
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#ifndef CVC5__THEORY__SETS__THEORY_SETS_REWRITER_H |
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#define CVC5__THEORY__SETS__THEORY_SETS_REWRITER_H |
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#include "theory/rewriter.h" |
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namespace cvc5 { |
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namespace theory { |
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namespace sets { |
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class TheorySetsRewriter : public TheoryRewriter |
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{ |
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public: |
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/** |
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* Rewrite a node into the normal form for the theory of sets. |
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* Called in post-order (really reverse-topological order) when |
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* traversing the expression DAG during rewriting. This is the |
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* main function of the rewriter, and because of the ordering, |
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* it can assume its children are all rewritten already. |
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* |
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* This function can return one of three rewrite response codes |
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* along with the rewritten node: |
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* |
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* REWRITE_DONE indicates that no more rewriting is needed. |
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* REWRITE_AGAIN means that the top-level expression should be |
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* rewritten again, but that its children are in final form. |
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* REWRITE_AGAIN_FULL means that the entire returned expression |
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* should be rewritten again (top-down with preRewrite(), then |
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* bottom-up with postRewrite()). |
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* |
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* Even if this function returns REWRITE_DONE, if the returned |
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* expression belongs to a different theory, it will be fully |
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* rewritten by that theory's rewriter. |
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*/ |
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RewriteResponse postRewrite(TNode node) override; |
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/** |
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* Rewrite a node into the normal form for the theory of sets |
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* in pre-order (really topological order)---meaning that the |
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* children may not be in the normal form. This is an optimization |
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* for theories with cancelling terms (e.g., 0 * (big-nasty-expression) |
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* in arithmetic rewrites to 0 without the need to look at the big |
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* nasty expression). Since it's only an optimization, the |
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* implementation here can do nothing. |
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*/ |
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RewriteResponse preRewrite(TNode node) override; |
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/** |
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* Rewrite an equality, in case special handling is required. |
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*/ |
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Node rewriteEquality(TNode equality) |
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{ |
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// often this will suffice |
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return postRewrite(equality).d_node; |
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} |
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private: |
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/** |
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* Returns true if elementTerm is in setTerm, where both terms are constants. |
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*/ |
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bool checkConstantMembership(TNode elementTerm, TNode setTerm); |
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}; /* class TheorySetsRewriter */ |
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} // namespace sets |
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} // namespace theory |
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} // namespace cvc5 |
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#endif /* CVC5__THEORY__SETS__THEORY_SETS_REWRITER_H */ |