Method followpos

gecode/minimodel/reg.cpp:562–648

  }

  forceinline MiniModel::PosSet*
  REG::Exp::followpos(MiniModel::PosSetAllocator& psm,
                      MiniModel::PosInfo* pi) {
    int p=0;

    using MiniModel::PosSet;
    using MiniModel::NodeInfo;
    using MiniModel::ExpInfo;

    Region region;

    Support::DynamicStack<ExpInfo,Region> todo(region);
    Support::DynamicStack<NodeInfo,Region> done(region);

    // Start with first expression to be processed
    todo.push(ExpInfo(this));

    do {
      if (todo.top().exp == nullptr) {
        todo.pop();
        done.push(NodeInfo(true,nullptr,nullptr));
      } else {
        switch (todo.top().exp->type) {
        case ET_SYMBOL:
          {
            pi[p].symbol = todo.pop().exp->data.symbol;
            PosSet* ps = new (psm) PosSet(p++);
            done.push(NodeInfo(false,ps,ps));
          }
          break;
        case ET_STAR:
          if (todo.top().open) {
            // Evaluate subexpression recursively
            todo.top().open = false;
            todo.push(todo.top().exp->data.kids[0]);
          } else {
            todo.pop();
            NodeInfo ni = done.pop();
            for (PosSet* ps = ni.lastpos; ps != nullptr; ps = ps->next)
              pi[ps->pos].followpos =
                PosSet::cup(psm,pi[ps->pos].followpos,ni.firstpos);
            done.push(NodeInfo(true,ni.firstpos,ni.lastpos));
          }
          break;
        case ET_CONC:
          if (todo.top().open) {
            // Evaluate subexpressions recursively
            todo.top().open = false;
            REG::Exp* e = todo.top().exp;
            todo.push(e->data.kids[1]);
            todo.push(e->data.kids[0]);
          } else {
            todo.pop();
            NodeInfo ni1 = done.pop();
            NodeInfo ni0 = done.pop();
            for (PosSet* ps = ni0.lastpos; ps != nullptr; ps = ps->next)
              pi[ps->pos].followpos =
                PosSet::cup(psm,pi[ps->pos].followpos,ni1.firstpos);