#include <iostream>
#include <string>
#include <vector>

// forward declaration
class PrintVisitor;

class Printable {
public:
  virtual void Print(PrintVisitor& visitor) = 0;
};

class PrintVisitor {
public:
  // Constructor
  PrintVisitor(int start, int stop, int step) :
    current( start ),
    stop( stop ),
    step( step ),
    col( 0 ),
    row( 0 )
  {
  }
  bool Done() { // opcode
    return current > stop;
  }
  void Print(std::string to_print) { // opcode
    std::cout << to_print;
  }
  void Newline() { // opcode
    std::cout << "\n"; 
    col = 0;
    row += 1;
  }
  void Integer() { // opcode
    std::cout << current;
    current += step;
  }
  void Row() { // opcode
    std::cout << row;
  }
  void Col() { // opcode
    std::cout << col;
    col += 1;
  }
private:
  // interpretive state (e.g. registers)
  int current;
  int stop;
  int step;
  int col;
  int row;
};


class Loop : public Printable {
public:
  // Constructor.
  explicit Loop(Printable& body) : body(body) {}
  void Print(PrintVisitor& visitor) {
    while (not visitor.Done()) {
      body.Print(visitor);
    }
  }
private:
  Printable& body;
};

class Literal : public Printable {
public:
  // Constructor.
  explicit Literal(std::string to_print) : to_print(to_print) {}
  void Print(PrintVisitor& visitor) {
    visitor.Print(to_print);
  }
private:
  std::string to_print;
};

class Newline : public Printable {
public:
  void Print(PrintVisitor& visitor) {
    visitor.Newline();
  }
};

class Integer : public Printable {
public:
  void Print(PrintVisitor& visitor) {
    visitor.Integer();
  }
};

class Row : public Printable {
public:
  void Print(PrintVisitor& visitor) {
    visitor.Row();
  }
};

class Col : public Printable {
public:
  void Print(PrintVisitor& visitor) {
    visitor.Col();
  }
};

class Sequence : public Printable {
public:
  // Mutator
  void Add(Printable& to_add) {
    to_print.push_back(&to_add);
  }
  void Print(PrintVisitor& visitor) {
    for (int i= 0; i < to_print.size(); ++i) {
      to_print[i]->Print(visitor);
    }
  }
private:
  std::vector<Printable*> to_print;
};

class ExampleReport : public Printable {
public:
  // Constructor
  ExampleReport() :
    tab_col_lit("\tcol"),
    c(),
    nl90,
    row_lit("row"),
    r,
    colon_tab_lit(":\t"),
    i,
    comma_tab_lit(",\t"),
    loop_body(),
    loop(loop_body),
    total()
  {
    loop_body.Add(row_lit);
    loop_body.Add(r);
    loop_body.Add(colon_tab_lit);
    loop_body.Add(i);
    loop_body.Add(comma_tab_lit);
    loop_body.Add(i);
    loop_body.Add(comma_tab_lit);
    loop_body.Add(i);
    loop_body.Add(nl);
    total.Add(tab_col_lit);
    total.Add(c);
    total.Add(tab_col_lit);
    total.Add(c);
    total.Add(tab_col_lit);
    total.Add(c);
    total.Add(nl);
    total.Add(loop);
  }
  void Print(PrintVisitor& visitor) {
    total.Print(visitor);
  }
private:
  Literal tab_col_lit;
  Col c;
  Newline nl;
  Literal row_lit;
  Row r;
  Literal colon_tab_lit;
  Integer i;
  Literal comma_tab_lit;
  Sequence loop_body;
  Loop loop;
  Sequence total;
};

int main(int argc, char* argv[]) {
  ExampleReport report;
  PrintVisitor visitor(10, 30, 3);
  report.Print(visitor);
  return 0;
}