From 80be200c84494a4f82ab30cb743b7758c67db5b5 Mon Sep 17 00:00:00 2001
From: Haniel Barbosa <hanielbbarbosa@gmail.com>
Date: Thu, 16 Aug 2018 11:18:11 -0500
Subject: Refactor apply2const (#2316)

---
 src/preprocessing/passes/apply_to_const.cpp | 108 ++++++++++++++++++++++++++++
 src/preprocessing/passes/apply_to_const.h   |  51 +++++++++++++
 2 files changed, 159 insertions(+)
 create mode 100644 src/preprocessing/passes/apply_to_const.cpp
 create mode 100644 src/preprocessing/passes/apply_to_const.h

(limited to 'src/preprocessing')

diff --git a/src/preprocessing/passes/apply_to_const.cpp b/src/preprocessing/passes/apply_to_const.cpp
new file mode 100644
index 000000000..bbe4439ec
--- /dev/null
+++ b/src/preprocessing/passes/apply_to_const.cpp
@@ -0,0 +1,108 @@
+/*********************                                                        */
+/*! \file apply_to_const.cpp
+ ** \verbatim
+ ** Top contributors (to current version):
+ **   Haniel Barbosa
+ ** This file is part of the CVC4 project.
+ ** Copyright (c) 2009-2018 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 The ApplyToConst preprocessing pass
+ **
+ ** Rewrites applies to constants
+ **/
+
+#include "preprocessing/passes/apply_to_const.h"
+
+#include "theory/rewriter.h"
+
+namespace CVC4 {
+namespace preprocessing {
+namespace passes {
+
+using namespace CVC4::theory;
+
+ApplyToConst::ApplyToConst(PreprocessingPassContext* preprocContext)
+    : PreprocessingPass(preprocContext, "apply-to-const"){};
+
+Node ApplyToConst::rewriteApplyToConst(TNode n, NodeMap& cache)
+{
+  Trace("rewriteApplyToConst") << "rewriteApplyToConst :: " << n << std::endl;
+
+  if (n.getMetaKind() == kind::metakind::CONSTANT
+      || n.getMetaKind() == kind::metakind::VARIABLE
+      || n.getMetaKind() == kind::metakind::NULLARY_OPERATOR)
+  {
+    return n;
+  }
+
+  if (cache.find(n) != cache.end())
+  {
+    Trace("rewriteApplyToConst") << "in cache :: " << cache[n] << std::endl;
+    return cache[n];
+  }
+
+  if (n.getKind() == kind::APPLY_UF)
+  {
+    if (n.getNumChildren() == 1 && n[0].isConst() && n[0].getType().isInteger())
+    {
+      stringstream ss;
+      ss << n.getOperator() << "_";
+      if (n[0].getConst<Rational>() < 0)
+      {
+        ss << "m" << -n[0].getConst<Rational>();
+      }
+      else
+      {
+        ss << n[0];
+      }
+      Node newvar =
+          NodeManager::currentNM()->mkSkolem(ss.str(),
+                                             n.getType(),
+                                             "rewriteApplyToConst skolem",
+                                             NodeManager::SKOLEM_EXACT_NAME);
+      cache[n] = newvar;
+      Trace("rewriteApplyToConst") << "made :: " << newvar << std::endl;
+      return newvar;
+    }
+    stringstream ss;
+    ss << "The rewrite-apply-to-const preprocessor is currently limited;\n"
+       << "it only works if all function symbols are unary and with Integer\n"
+       << "domain, and all applications are to integer values.\n"
+       << "Found application: " << n;
+    Unhandled(ss.str());
+  }
+
+  NodeBuilder<> builder(n.getKind());
+  if (n.getMetaKind() == kind::metakind::PARAMETERIZED)
+  {
+    builder << n.getOperator();
+  }
+  for (unsigned i = 0; i < n.getNumChildren(); ++i)
+  {
+    builder << rewriteApplyToConst(n[i], cache);
+  }
+  Node rewr = builder;
+  cache[n] = rewr;
+  Trace("rewriteApplyToConst") << "built :: " << rewr << std::endl;
+  return rewr;
+}
+
+PreprocessingPassResult ApplyToConst::applyInternal(
+    AssertionPipeline* assertionsToPreprocess)
+{
+  NodeMap cache;
+  for (unsigned i = 0, size = assertionsToPreprocess->size(); i < size; ++i)
+  {
+    assertionsToPreprocess->replace(i,
+                                    Rewriter::rewrite(rewriteApplyToConst(
+                                        (*assertionsToPreprocess)[i], cache)));
+  }
+  return PreprocessingPassResult::NO_CONFLICT;
+}
+
+}  // namespace passes
+}  // namespace preprocessing
+}  // namespace CVC4
diff --git a/src/preprocessing/passes/apply_to_const.h b/src/preprocessing/passes/apply_to_const.h
new file mode 100644
index 000000000..9d5072023
--- /dev/null
+++ b/src/preprocessing/passes/apply_to_const.h
@@ -0,0 +1,51 @@
+/*********************                                                        */
+/*! \file apply_to_const.h
+ ** \verbatim
+ ** Top contributors (to current version):
+ **   Haniel Barbosa
+ ** This file is part of the CVC4 project.
+ ** Copyright (c) 2009-2018 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 The ApplyToConst preprocessing pass
+ **
+ ** Rewrites applies to constants
+ **/
+
+#include "cvc4_private.h"
+
+#ifndef __CVC4__PREPROCESSING__PASSES__APPLY_TO_CONST_H
+#define __CVC4__PREPROCESSING__PASSES__APPLY_TO_CONST_H
+
+#include <unordered_map>
+
+#include "expr/node.h"
+#include "preprocessing/preprocessing_pass.h"
+#include "preprocessing/preprocessing_pass_context.h"
+
+namespace CVC4 {
+namespace preprocessing {
+namespace passes {
+
+using NodeMap = std::unordered_map<Node, Node, NodeHashFunction>;
+
+class ApplyToConst : public PreprocessingPass
+{
+ public:
+  ApplyToConst(PreprocessingPassContext* preprocContext);
+
+ protected:
+  PreprocessingPassResult applyInternal(
+      AssertionPipeline* assertionsToPreprocess) override;
+
+ private:
+  Node rewriteApplyToConst(TNode n, NodeMap& cache);
+};
+
+}  // namespace passes
+}  // namespace preprocessing
+}  // namespace CVC4
+
+#endif /* __CVC4__PREPROCESSING__PASSES__APPLY_TO_CONST_H */
-- 
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