contracts.h

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#ifndef CONTRACTS_GROUP
#define CONTRACTS_GROUP

/*****************************************************************************\
*                                                                             *
*  Name   : contracts                                                         *
*  Author : Chris Koeritz                                                     *
*                                                                             *
*******************************************************************************
* Copyright (c) 1989-$now By Author.  This program is free software; you can  *
* redistribute it and/or modify it under the terms of the GNU General Public  *
* License as published by the Free Software Foundation; either version 2 of   *
* the License or (at your option) any later version.  This is online at:      *
*     http://www.fsf.org/copyleft/gpl.html                                    *
* Please send any updates to: fred@gruntose.com                               *
\*****************************************************************************/

#include "outcome.h"

namespace basis {

// forward declarations.
class base_string;



class attribute : public virtual root_object
{
public:
  virtual const root_object &get() const = 0;
  virtual void set(const root_object &new_value) = 0;
};


class equalizable : public virtual root_object
{
public:
  virtual bool equal_to(const equalizable &s2) const = 0;
  virtual bool operator == (const equalizable &s2) const { return equal_to(s2); }
};



class orderable : public virtual equalizable
{
public:
  virtual bool less_than(const orderable &s2) const  = 0;
  virtual bool operator < (const orderable &s2) const { return less_than(s2); }
};



class base_logger : public virtual root_object
{
public:
  virtual outcome log(const base_string &info, int filter) = 0;

};


#define DEFINE_FILTER(NAME, CURRENT_VALUE, INFO_STRING) NAME = CURRENT_VALUE

enum root_logging_filters {
  DEFINE_FILTER(NEVER_PRINT, -1, "This diagnostic entry should be dropped and never seen"),
  DEFINE_FILTER(ALWAYS_PRINT, 0, "This diagnostic entry will always be shown or recorded")
};



class base_synchronizer : public virtual root_object
{
public:
  virtual void establish_lock() = 0;
  virtual void repeal_lock() = 0;
};



class clonable : public virtual root_object
{
public:
  virtual clonable *clone() const = 0;
};



class nameable : public virtual root_object
{
public:
  virtual const char *class_name() const = 0;

};



class text_formable : public virtual nameable
{
public:
  virtual const char *class_name() const = 0;  // forwarded requirement from nameable.

  virtual void text_form(base_string &state_fill) const = 0;

};



class hoople_standard : public virtual text_formable, public virtual equalizable
{
public:
  // this is a union class and has no extra behavior beyond its bases.
};



class text_streamable : public virtual nameable
{
public:
  virtual bool produce(base_string &target) const = 0;

  virtual bool consume(const base_string &source) = 0;

};

} //namespace.

#endif