// ObjectFormat.h

#ifndef ObjectFormat_H
#define ObjectFormat_H

// A format is inserted in a stram and dictates the behavior when the
// following objects are are inserted or extracted from that stream:
//   begin_object - signals the start of a new object
//   end_object - signals the end of the current object
//   new_line - starts a new line of output with appropriate prefix
//              (including indentation)
//
// For example
//
// cout << Format( "{ ", " }", "  ", ">>> " );
// cout << begin_object << "A = " << a << new_line << "B = " << b;
// cout << end_object;
//
// would produce:
//
// >>> { A = 1.234
// >>>   B = 6 }

//**********************************************************************

#include <iosfwd>
#include <string>

using std::ostream;
using std::string;

class ObjectFormat {

public:

  // Print the format for a stream.
  static void print_format(ostream& stream);

private:

  string _begin;
  string _end;
  string _indent;
  string _prefix;
  int _depth;

public:  // constructor

  // Constructor.
  // begin = string to appear at the start of an object
  //         '\n' is replaced with new_line.
  // end = string to appear at the end of an object
  // new_line = string to appear between "lines"
  // indent = string used to indent
  // prefix = string to appear in front of each line
  ObjectFormat(string begin="", string end ="", string indent ="",
         string prefix ="");

public:  // non-const functions

  // Return the start of object string and increment object depth.
  string begin_object();

  // Return the end of object string and decrement object depth.
  string end_object();

  // Return the prefix for a new line.
  string new_line();

  // Copy the state (depth) from another format.
  void copy_state(const ObjectFormat& fmt);

public:  // non-const functions

  // Return the start of object string.
  string get_begin_object_string() const { return _begin; }

  // Return the start of object string.
  string get_end_object_string() const { return _end; }

  // Return the indent string.
  string get_indent_string() const { return _indent; }

  // Return the prefix string.
  string get_prefix_string() const { return _prefix; }

};

//**********************************************************************

// Types for operator<<.
class BeginObject { };
class EndObject { };
class NewLine { };

//**********************************************************************

// Output stream operators.

// Associate a format with a stream.
ostream& operator<<(ostream& stream, const ObjectFormat& rhs);

// Indicate the start of an object.
// The start of object string is written to the stream.
ostream& operator<<(ostream& stream, const BeginObject& rhs);

// Indicate the end of an object.
// The end of object string is written to the stream.
ostream& operator<<(ostream& stream, const EndObject& rhs);

// Start a new line and indent for the current object.
// Do NOT call just before end_object;
ostream& operator<<(ostream& stream, const NewLine& rhs);

//**********************************************************************

// Objects intended for stream insertion.

// Assign the default format.
extern ObjectFormat null_format;

// Assign format which indents objects.
extern ObjectFormat indented_format;

// Assign format which indents and surrounds objects with brackets: [].
extern ObjectFormat bracketed_format;

// Assign format which indents and surrounds objects with braces: [].
extern ObjectFormat braced_format;

// Indicate the start of an objects.
extern BeginObject begin_object;

// Indicate the end of an object.
extern EndObject end_object;

// Indicate a new line.
extern NewLine new_line;

//**********************************************************************

#endif