From e4a29a6033ecc7ba5ec266f37e8f151f09ead020 Mon Sep 17 00:00:00 2001
From: mudathirmahgoub <mudathirmahgoub@gmail.com>
Date: Tue, 22 Sep 2020 16:59:41 -0500
Subject: Add skeleton for theory of bags (multisets) (#5100)

This PR adds initial headers and mostly empty source files for the theory of bags (multisets).
It acts as a basis for future commits.
It includes straightforward implementation for typing rules an enumerator for bags.
---
 src/theory/bags/term_registry.h | 63 +++++++++++++++++++++++++++++++++++++++++
 1 file changed, 63 insertions(+)
 create mode 100644 src/theory/bags/term_registry.h

(limited to 'src/theory/bags/term_registry.h')

diff --git a/src/theory/bags/term_registry.h b/src/theory/bags/term_registry.h
new file mode 100644
index 000000000..d284126ee
--- /dev/null
+++ b/src/theory/bags/term_registry.h
@@ -0,0 +1,63 @@
+/*********************                                                        */
+/*! \file term_registry.h
+ ** \verbatim
+ ** Top contributors (to current version):
+ **   Mudathir Mohamed
+ ** This file is part of the CVC4 project.
+ ** Copyright (c) 2009-2020 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 Bags state object
+ **/
+
+#include "cvc4_private.h"
+
+#ifndef CVC4__THEORY__BAGS__TERM_REGISTRY_H
+#define CVC4__THEORY__BAGS__TERM_REGISTRY_H
+
+#include <map>
+#include <vector>
+
+#include "context/cdhashmap.h"
+#include "theory/bags/inference_manager.h"
+#include "theory/bags/solver_state.h"
+
+namespace CVC4 {
+namespace theory {
+namespace bags {
+
+/**
+ * Term registry, the purpose of this class is to maintain a database of
+ * commonly used terms, and mappings from bags to their "proxy variables".
+ */
+class TermRegistry
+{
+  typedef context::CDHashMap<Node, Node, NodeHashFunction> NodeMap;
+
+ public:
+  TermRegistry(SolverState& state, InferenceManager& im);
+
+  /**
+   * Returns the existing empty bag for type tn
+   * or creates a new one and returns it.
+   **/
+  Node getEmptyBag(TypeNode tn);
+
+ private:
+  /** The inference manager */
+  InferenceManager& d_im;
+  /** Map from bag terms to their proxy variables */
+  NodeMap d_proxy;
+  /** Backwards map of above */
+  NodeMap d_proxy_to_term;
+  /** Map from types to empty bag of that type */
+  std::map<TypeNode, Node> d_emptybag;
+}; /* class Term */
+
+}  // namespace bags
+}  // namespace theory
+}  // namespace CVC4
+
+#endif /* CVC4__THEORY__BAGS__TERM_REGISTRY_H */
-- 
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