Remove some dead code from theory strings (#2125)

1 files changed, 0 insertions, 612 deletions

diff --git a/src/theory/strings/regexp_operation.cpp b/src/theory/strings/regexp_operation.cpp
index 0eccc72c7..e130d5e4b 100644
--- a/src/theory/strings/regexp_operation.cpp
+++ b/src/theory/strings/regexp_operation.cpp
@@ -634,76 +634,6 @@ Node RegExpOpr::derivativeSingle( Node r, CVC4::String c ) {
   return retNode;
 }
 
-//TODO:
-bool RegExpOpr::guessLength( Node r, int &co ) {
-  int k = r.getKind();
-  switch( k ) {
-    case kind::STRING_TO_REGEXP:
-    {
-      if(r[0].isConst()) {
-        co += r[0].getConst< CVC4::String >().size();
-        return true;
-      } else {
-        return false;
-      }
-    }
-      break;
-    case kind::REGEXP_CONCAT:
-    {
-      for(unsigned i=0; i<r.getNumChildren(); ++i) {
-        if(!guessLength( r[i], co)) {
-          return false;
-        }
-      }
-      return true;
-    }
-      break;
-    case kind::REGEXP_UNION:
-    {
-      int g_co;
-      for(unsigned i=0; i<r.getNumChildren(); ++i) {
-        int cop = 0;
-        if(!guessLength( r[i], cop)) {
-          return false;
-        }
-        if(i == 0) {
-          g_co = cop;
-        } else {
-          g_co = gcd(g_co, cop);
-        }
-      }
-      return true;
-    }
-      break;
-    case kind::REGEXP_INTER:
-    {
-      int g_co;
-      for(unsigned i=0; i<r.getNumChildren(); ++i) {
-        int cop = 0;
-        if(!guessLength( r[i], cop)) {
-          return false;
-        }
-        if(i == 0) {
-          g_co = cop;
-        } else {
-          g_co = gcd(g_co, cop);
-        }
-      }
-      return true;
-    }
-      break;
-    case kind::REGEXP_STAR:
-    {
-      co = 0;
-      return true;
-    }
-      break;
-    default:
-      Trace("strings-error") << "Unsupported term: " << mkString( r ) << " in membership of RegExp." << std::endl;
-      return false;
-  }
-}
-
 void RegExpOpr::firstChars( Node r, std::set<unsigned char> &pcset, SetNodes &pvset ) {
   Trace("regexp-fset") << "Start FSET(" << mkString(r) << ")" << std::endl;
   std::map< Node, std::pair< std::set<unsigned char>, SetNodes > >::const_iterator itr = d_fset_cache.find(r);
@@ -809,124 +739,6 @@ void RegExpOpr::firstChars( Node r, std::set<unsigned char> &pcset, SetNodes &pv
   }
 }
 
-bool RegExpOpr::follow( Node r, CVC4::String c, std::vector< unsigned char > &vec_chars ) {
-  int k = r.getKind();
-  switch( k ) {
-    case kind::STRING_TO_REGEXP:
-    {
-      if(r[0].isConst()) {
-        if(r[0] != d_emptyString) {
-          unsigned char t1 = r[0].getConst< CVC4::String >().getFirstChar();
-          if(c.isEmptyString()) {
-            vec_chars.push_back( t1 );
-            return true;
-          } else {
-            unsigned char t2 = c.getFirstChar();
-            if(t1 != t2) {
-              return false;
-            } else {
-              if(c.size() >= 2) {
-                vec_chars.push_back( c.substr(1,1).getFirstChar() );
-              } else {
-                vec_chars.push_back( '\0' );
-              }
-              return true;
-            }
-          }
-        } else {
-          return false;
-        }
-      } else {
-        return false;
-      }
-    }
-      break;
-    case kind::REGEXP_CONCAT:
-    {
-      for(unsigned i=0; i<r.getNumChildren(); ++i) {
-        if( follow(r[i], c, vec_chars) ) {
-          if(vec_chars[vec_chars.size() - 1] == '\0') {
-            vec_chars.pop_back();
-            c = d_emptyString.getConst< CVC4::String >();
-          }
-        } else {
-          return false;
-        }
-      }
-      vec_chars.push_back( '\0' );
-      return true;
-    }
-      break;
-    case kind::REGEXP_UNION:
-    {
-      bool flag = false;
-      for(unsigned i=0; i<r.getNumChildren(); ++i) {
-        if( follow(r[i], c, vec_chars) ) {
-          flag=true;
-        }
-      }
-      return flag;
-    }
-      break;
-    case kind::REGEXP_INTER:
-    {
-      std::vector< unsigned char > vt2;
-      for(unsigned i=0; i<r.getNumChildren(); ++i) {
-        std::vector< unsigned char > v_tmp;
-        if( !follow(r[i], c, v_tmp) ) {
-          return false;
-        }
-        std::vector< unsigned char > vt3(vt2);
-        vt2.clear();
-        std::set_intersection( vt3.begin(), vt3.end(), v_tmp.begin(), v_tmp.end(), vt2.begin() );
-        if(vt2.size() == 0) {
-          return false;
-        }
-      }
-      vec_chars.insert( vec_chars.end(), vt2.begin(), vt2.end() );
-      return true;
-    }
-      break;
-    case kind::REGEXP_STAR:
-    {
-      if(follow(r[0], c, vec_chars)) {
-        if(vec_chars[vec_chars.size() - 1] == '\0') {
-          if(c.isEmptyString()) {
-            return true;
-          } else {
-            vec_chars.pop_back();
-            c = d_emptyString.getConst< CVC4::String >();
-            return follow(r[0], c, vec_chars);
-          }
-        } else {
-          return true;
-        }
-      } else {
-        vec_chars.push_back( '\0' );
-        return true;
-      }
-    }
-      break;
-    default: {
-      Trace("strings-error") << "Unsupported term: " << mkString( r ) << " in follow of RegExp." << std::endl;
-      //AlwaysAssert( false );
-      //return Node::null();
-      return false;
-    }
-  }
-}
-
-Node RegExpOpr::mkAllExceptOne( unsigned char exp_c ) {
-  std::vector< Node > vec_nodes;
-  for(unsigned char c=d_char_start; c<=d_char_end; ++c) {
-    if(c != exp_c ) {
-      Node n = NodeManager::currentNM()->mkNode( kind::STRING_TO_REGEXP, NodeManager::currentNM()->mkConst( ::CVC4::String( c ) ) );
-      vec_nodes.push_back( n );
-    }
-  }
-  return NodeManager::currentNM()->mkNode( kind::REGEXP_UNION, vec_nodes );
-}
-
 //simplify
 void RegExpOpr::simplify(Node t, std::vector< Node > &new_nodes, bool polarity) {
   Trace("strings-regexp-simpl") << "RegExp-Simpl starts with " << t << ", polarity=" << polarity << std::endl;
@@ -1297,99 +1109,6 @@ void RegExpOpr::simplifyPRegExp( Node s, Node r, std::vector< Node > &new_nodes
   }
 }
 
-void RegExpOpr::getCharSet( Node r, std::set<unsigned char> &pcset, SetNodes &pvset ) {
-  std::map< Node, std::pair< std::set<unsigned char>, SetNodes > >::const_iterator itr = d_cset_cache.find(r);
-  if(itr != d_cset_cache.end()) {
-    pcset.insert((itr->second).first.begin(), (itr->second).first.end());
-    pvset.insert((itr->second).second.begin(), (itr->second).second.end());
-  } else {
-    std::set<unsigned char> cset;
-    SetNodes vset;
-    int k = r.getKind();
-    switch( k ) {
-      case kind::REGEXP_EMPTY: {
-        break;
-      }
-      case kind::REGEXP_SIGMA: {
-        for(unsigned char i='\0'; i<=d_lastchar; i++) {
-          cset.insert(i);
-        }
-        break;
-      }
-      case kind::REGEXP_RANGE: {
-        unsigned char a = r[0].getConst<String>().getFirstChar();
-        unsigned char b = r[1].getConst<String>().getFirstChar();
-        for(unsigned char i=a; i<=b; i++) {
-          cset.insert(i);
-        }
-        break;
-      }
-      case kind::STRING_TO_REGEXP: {
-        Node st = Rewriter::rewrite(r[0]);
-        if(st.isConst()) {
-          CVC4::String s = st.getConst< CVC4::String >();
-          cset.insert(s.getVec().begin(), s.getVec().end());
-        } else if(st.getKind() == kind::VARIABLE) {
-          vset.insert( st );
-        } else {
-          for(unsigned i=0; i<st.getNumChildren(); i++) {
-            if(st[i].isConst()) {
-              CVC4::String s = st[i].getConst< CVC4::String >();
-              cset.insert(s.getVec().begin(), s.getVec().end());
-            } else {
-              vset.insert( st[i] );
-            }
-          }
-        }
-        break;
-      }
-      case kind::REGEXP_CONCAT: {
-        for(unsigned i=0; i<r.getNumChildren(); i++) {
-          getCharSet(r[i], cset, vset);
-        }
-        break;
-      }
-      case kind::REGEXP_UNION: {
-        for(unsigned i=0; i<r.getNumChildren(); i++) {
-          getCharSet(r[i], cset, vset);
-        }
-        break;
-      }
-      case kind::REGEXP_INTER: {
-        //TODO: Overapproximation for now
-        //for(unsigned i=0; i<r.getNumChildren(); i++) {
-          //getCharSet(r[i], cset, vset);
-        //}
-        getCharSet(r[0], cset, vset);
-        break;
-      }
-      case kind::REGEXP_STAR: {
-        getCharSet(r[0], cset, vset);
-        break;
-      }
-      case kind::REGEXP_LOOP: {
-        getCharSet(r[0], cset, vset);
-        break;
-      }
-      default: {
-        //Trace("strings-error") << "Unsupported term: " << r << " in getCharSet." << std::endl;
-        Unreachable();
-      }
-    }
-    pcset.insert(cset.begin(), cset.end());
-    pvset.insert(vset.begin(), vset.end());
-    std::pair< std::set<unsigned char>, SetNodes > p(cset, vset);
-    d_cset_cache[r] = p;
-
-    Trace("regexp-cset") << "CSET( " << mkString(r) << " ) = { ";
-    for(std::set<unsigned char>::const_iterator itr = cset.begin();
-      itr != cset.end(); itr++) {
-        Trace("regexp-cset") << (*itr) << ",";
-      }
-    Trace("regexp-cset") << " }" << std::endl;
-  }
-}
-
 bool RegExpOpr::isPairNodesInSet(std::set< PairNodes > &s, Node n1, Node n2) {
   for(std::set< PairNodes >::const_iterator itr = s.begin();
       itr != s.end(); ++itr) {
@@ -1734,337 +1453,6 @@ Node RegExpOpr::intersect(Node r1, Node r2, bool &spflag) {
   }
 }
 
-Node RegExpOpr::complement(Node r, int &ret) {
-  Node rNode;
-  ret = 1;
-  if(d_compl_cache.find(r) != d_compl_cache.end()) {
-    rNode = d_compl_cache[r].first;
-    ret = d_compl_cache[r].second;
-  } else {
-    if(r == d_emptyRegexp) {
-      rNode = d_sigma_star;
-    } else if(r == d_emptySingleton) {
-      rNode = NodeManager::currentNM()->mkNode(kind::REGEXP_CONCAT, d_sigma, d_sigma_star);
-    } else if(!checkConstRegExp(r)) {
-      //TODO: var to be extended
-      ret = 0;
-    } else {
-      std::set<unsigned char> cset;
-      SetNodes vset;
-      firstChars(r, cset, vset);
-      std::vector< Node > vec_nodes;
-      for(unsigned char i=0; i<=d_lastchar; i++) {
-        CVC4::String c(i);
-        Node n = NodeManager::currentNM()->mkNode(kind::STRING_TO_REGEXP, NodeManager::currentNM()->mkConst(c));
-        Node r2;
-        if(cset.find(i) == cset.end()) {
-          r2 = d_sigma_star;
-        } else {
-          int rt;
-          derivativeS(r, c, r2);
-          if(r2 == r) {
-            r2 = d_emptyRegexp;
-          } else {
-            r2 = complement(r2, rt);
-          }
-        }
-        n = Rewriter::rewrite(NodeManager::currentNM()->mkNode(kind::REGEXP_CONCAT, n, r2));
-        vec_nodes.push_back(n);
-      }
-      rNode = vec_nodes.size()==0? d_emptyRegexp : vec_nodes.size()==1? vec_nodes[0] :
-            NodeManager::currentNM()->mkNode(kind::REGEXP_UNION, vec_nodes);
-    }
-    rNode = Rewriter::rewrite(rNode);
-    std::pair< Node, int > p(rNode, ret);
-    d_compl_cache[r] = p;
-  }
-  Trace("regexp-compl") << "COMPL( " << mkString(r) << " ) = " << mkString(rNode) << ", ret=" << ret << std::endl;
-  return rNode;
-}
-
-void RegExpOpr::splitRegExp(Node r, std::vector< PairNodes > &pset) {
-  Assert(checkConstRegExp(r));
-  if(d_split_cache.find(r) != d_split_cache.end()) {
-    pset = d_split_cache[r];
-  } else {
-    switch( r.getKind() ) {
-      case kind::REGEXP_EMPTY: {
-        break;
-      }
-      case kind::REGEXP_OPT: {
-        PairNodes tmp(d_emptySingleton, d_emptySingleton);
-        pset.push_back(tmp);
-      }
-      case kind::REGEXP_RANGE:
-      case kind::REGEXP_SIGMA: {
-        PairNodes tmp1(d_emptySingleton, r);
-        PairNodes tmp2(r, d_emptySingleton);
-        pset.push_back(tmp1);
-        pset.push_back(tmp2);
-        break;
-      }
-      case kind::STRING_TO_REGEXP: {
-        Assert(r[0].isConst());
-        CVC4::String s = r[0].getConst< CVC4::String >();
-        PairNodes tmp1(d_emptySingleton, r);
-        pset.push_back(tmp1);
-        for(unsigned i=1; i<s.size(); i++) {
-          CVC4::String s1 = s.substr(0, i);
-          CVC4::String s2 = s.substr(i);
-          Node n1 = NodeManager::currentNM()->mkNode(kind::STRING_TO_REGEXP, NodeManager::currentNM()->mkConst(s1));
-          Node n2 = NodeManager::currentNM()->mkNode(kind::STRING_TO_REGEXP, NodeManager::currentNM()->mkConst(s2));
-          PairNodes tmp3(n1, n2);
-          pset.push_back(tmp3);
-        }
-        PairNodes tmp2(r, d_emptySingleton);
-        pset.push_back(tmp2);
-        break;
-      }
-      case kind::REGEXP_CONCAT: {
-        for(unsigned i=0; i<r.getNumChildren(); i++) {
-          std::vector< PairNodes > tset;
-          splitRegExp(r[i], tset);
-          std::vector< Node > hvec;
-          std::vector< Node > tvec;
-          for(unsigned j=0; j<=i; j++) {
-            hvec.push_back(r[j]);
-          }
-          for(unsigned j=i; j<r.getNumChildren(); j++) {
-            tvec.push_back(r[j]);
-          }
-          for(unsigned j=0; j<tset.size(); j++) {
-            hvec[i] = tset[j].first;
-            tvec[0] = tset[j].second;
-            Node r1 = Rewriter::rewrite( hvec.size()==1?hvec[0]:NodeManager::currentNM()->mkNode(kind::REGEXP_CONCAT, hvec) );
-            Node r2 = Rewriter::rewrite( tvec.size()==1?tvec[0]:NodeManager::currentNM()->mkNode(kind::REGEXP_CONCAT, tvec) );
-            PairNodes tmp2(r1, r2);
-            pset.push_back(tmp2);
-          }
-        }
-        break;
-      }
-      case kind::REGEXP_UNION: {
-        for(unsigned i=0; i<r.getNumChildren(); ++i) {
-          std::vector< PairNodes > tset;
-          splitRegExp(r[i], tset);
-          pset.insert(pset.end(), tset.begin(), tset.end());
-        }
-        break;
-      }
-      case kind::REGEXP_INTER: {
-        bool spflag = false;
-        Node tmp = r[0];
-        for(unsigned i=1; i<r.getNumChildren(); i++) {
-          tmp = intersect(tmp, r[i], spflag);
-        }
-        splitRegExp(tmp, pset);
-        break;
-      }
-      case kind::REGEXP_STAR: {
-        std::vector< PairNodes > tset;
-        splitRegExp(r[0], tset);
-        PairNodes tmp1(d_emptySingleton, d_emptySingleton);
-        pset.push_back(tmp1);
-        for(unsigned i=0; i<tset.size(); i++) {
-          Node r1 = tset[i].first==d_emptySingleton ? r : NodeManager::currentNM()->mkNode(kind::REGEXP_CONCAT, r, tset[i].first);
-          Node r2 = tset[i].second==d_emptySingleton ? r : NodeManager::currentNM()->mkNode(kind::REGEXP_CONCAT, tset[i].second, r);
-          PairNodes tmp2(r1, r2);
-          pset.push_back(tmp2);
-        }
-        break;
-      }
-      case kind::REGEXP_LOOP: {
-        unsigned l = r[1].getConst<Rational>().getNumerator().toUnsignedInt();
-        unsigned u = r[2].getConst<Rational>().getNumerator().toUnsignedInt();
-        if(l == u) {
-          //R^n
-          if(l == 0) {
-            PairNodes tmp1(d_emptySingleton, d_emptySingleton);
-            pset.push_back(tmp1);
-          } else if(l == 1) {
-            splitRegExp(r[0], pset);
-          } else {
-            std::vector< PairNodes > tset;
-            splitRegExp(r[0], tset);
-            for(unsigned j=0; j<l; j++) {
-              Node num1 = NodeManager::currentNM()->mkConst(CVC4::Rational(j));
-              Node r1 = j==0? d_emptySingleton : j==1? r[0] : NodeManager::currentNM()->mkNode(kind::REGEXP_LOOP, r[0], num1, num1);
-              unsigned j2 = l - j - 1;
-              Node num2 = NodeManager::currentNM()->mkConst(CVC4::Rational(j2));
-              Node r2 = j2==0? d_emptySingleton : j2==1? r[0] : NodeManager::currentNM()->mkNode(kind::REGEXP_LOOP, r[0], num2, num2);
-              for(unsigned i=0; i<tset.size(); i++) {
-                r1 = tset[i].first==d_emptySingleton? r1 : NodeManager::currentNM()->mkNode(kind::REGEXP_CONCAT, r1, tset[i].first);
-                r2 = tset[i].second==d_emptySingleton? r2 : NodeManager::currentNM()->mkNode(kind::REGEXP_CONCAT, tset[i].second, r2);
-                PairNodes tmp2(r1, r2);
-                pset.push_back(tmp2);
-              }
-            }
-          }
-        } else {
-          //R{0,n}
-          PairNodes tmp1(d_emptySingleton, d_emptySingleton);
-          pset.push_back(tmp1);
-          std::vector< PairNodes > tset;
-          splitRegExp(r[0], tset);
-          pset.insert(pset.end(), tset.begin(), tset.end());
-          for(unsigned k=2; k<=u; k++) {
-            for(unsigned j=0; j<k; j++) {
-              Node num1 = NodeManager::currentNM()->mkConst(CVC4::Rational(j));
-              Node r1 = j==0? d_emptySingleton : j==1? r[0] : NodeManager::currentNM()->mkNode(kind::REGEXP_LOOP, r[0], num1, num1);
-              unsigned j2 = k - j - 1;
-              Node num2 = NodeManager::currentNM()->mkConst(CVC4::Rational(j2));
-              Node r2 = j2==0? d_emptySingleton : j2==1? r[0] : NodeManager::currentNM()->mkNode(kind::REGEXP_LOOP, r[0], num2, num2);
-              for(unsigned i=0; i<tset.size(); i++) {
-                r1 = tset[i].first==d_emptySingleton? r1 : NodeManager::currentNM()->mkNode(kind::REGEXP_CONCAT, r1, tset[i].first);
-                r2 = tset[i].second==d_emptySingleton? r2 : NodeManager::currentNM()->mkNode(kind::REGEXP_CONCAT, tset[i].second, r2);
-                PairNodes tmp2(r1, r2);
-                pset.push_back(tmp2);
-              }
-            }
-          }
-        }
-        break;
-      }
-      case kind::REGEXP_PLUS: {
-        std::vector< PairNodes > tset;
-        splitRegExp(r[0], tset);
-        for(unsigned i=0; i<tset.size(); i++) {
-          Node r1 = NodeManager::currentNM()->mkNode(kind::REGEXP_CONCAT, r, tset[i].first);
-          Node r2 = NodeManager::currentNM()->mkNode(kind::REGEXP_CONCAT, tset[i].second, r);
-          PairNodes tmp2(r1, r2);
-          pset.push_back(tmp2);
-        }
-        break;
-      }
-      default: {
-        Trace("strings-error") << "Unsupported term: " << r << " in splitRegExp." << std::endl;
-        Assert( false );
-        //return Node::null();
-      }
-    }
-    d_split_cache[r] = pset;
-  }
-}
-
-void RegExpOpr::flattenRegExp(Node r, std::vector< std::pair< CVC4::String, unsigned > > &fvec) {
-  Assert(false);
-  Assert(checkConstRegExp(r));
-  switch( r.getKind() ) {
-      case kind::REGEXP_EMPTY: {
-        //TODO
-        break;
-      }
-      case kind::REGEXP_SIGMA: {
-        CVC4::String s("a");
-        std::pair< CVC4::String, unsigned > tmp(s, 0);
-        //TODO
-        break;
-      }
-      case kind::STRING_TO_REGEXP: {
-        Assert(r[0].isConst());
-        CVC4::String s = r[0].getConst< CVC4::String >();
-        std::pair< CVC4::String, unsigned > tmp(s, 0);
-        //TODO
-        break;
-      }
-      case kind::REGEXP_CONCAT: {
-        for(unsigned i=0; i<r.getNumChildren(); i++) {
-          //TODO
-        }
-        break;
-      }
-      case kind::REGEXP_UNION: {
-        for(unsigned i=0; i<r.getNumChildren(); ++i) {
-          //TODO
-        }
-        break;
-      }
-      case kind::REGEXP_INTER: {
-        //TODO
-        break;
-      }
-      case kind::REGEXP_STAR: {
-        //TODO
-        break;
-      }
-      case kind::REGEXP_LOOP: {
-        //TODO
-        break;
-      }
-      default: {
-        Unreachable();
-      }
-  }
-}
-
-void RegExpOpr::disjunctRegExp(Node r, std::vector<Node> &vec_or) {
-  switch(r.getKind()) {
-      case kind::REGEXP_EMPTY: {
-        vec_or.push_back(r);
-        break;
-      }
-      case kind::REGEXP_SIGMA: {
-        vec_or.push_back(r);
-        break;
-      }
-      case kind::REGEXP_RANGE: {
-        vec_or.push_back(r);
-        break;
-      }
-      case kind::STRING_TO_REGEXP: {
-        vec_or.push_back(r);
-        break;
-      }
-      case kind::REGEXP_CONCAT: {
-        disjunctRegExp(r[0], vec_or);
-        for(unsigned i=1; i<r.getNumChildren(); i++) {
-          std::vector<Node> vec_con;
-          disjunctRegExp(r[i], vec_con);
-          std::vector<Node> vec_or2;
-          for(unsigned k1=0; k1<vec_or.size(); k1++) {
-            for(unsigned k2=0; k2<vec_con.size(); k2++) {
-              Node tmp = Rewriter::rewrite( NodeManager::currentNM()->mkNode(kind::REGEXP_CONCAT, vec_or[k1], vec_con[k2]) );
-              if(std::find(vec_or2.begin(), vec_or2.end(), tmp) == vec_or2.end()) {
-                vec_or2.push_back( tmp );
-              }
-            }
-          }
-          vec_or = vec_or2;
-        }
-        break;
-      }
-      case kind::REGEXP_UNION: {
-        for(unsigned i=0; i<r.getNumChildren(); ++i) {
-          std::vector<Node> vec_or2;
-          disjunctRegExp(r[i], vec_or2);
-          vec_or.insert(vec_or.end(), vec_or2.begin(), vec_or2.end());
-        }
-        break;
-      }
-      case kind::REGEXP_INTER: {
-        Assert(checkConstRegExp(r));
-        Node rtmp = r[0];
-        bool spflag = false;
-        for(unsigned i=1; i<r.getNumChildren(); ++i) {
-          rtmp = intersect(rtmp, r[i], spflag);
-        }
-        disjunctRegExp(rtmp, vec_or);
-        break;
-      }
-      case kind::REGEXP_STAR: {
-        vec_or.push_back(r);
-        break;
-      }
-      case kind::REGEXP_LOOP: {
-        vec_or.push_back(r);
-        break;
-      }
-      default: {
-        Unreachable();
-      }
-  }
-}
-
 //printing
 std::string RegExpOpr::niceChar(Node r) {
   if(r.isConst()) {