bool_set File Reference

#include <typeinfo>
#include <iostream>
#include <tr2/bool_set.tcc>

Macros
#define	_GLIBCXX_TR2_BOOL_SET   1

Functions
namespace std	_GLIBCXX_VISIBILITY (default)

Detailed Description

This is a TR2 C++ Library header.

Macro Definition Documentation

#define _GLIBCXX_TR2_BOOL_SET   1

Function Documentation

namespace std _GLIBCXX_VISIBILITY

(

default

)

bool_set

See N2136, Bool_set: multi-valued logic by Hervé Brönnimann, Guillaume Melquiond, Sylvain Pion.

The implicit conversion to bool is slippery! I may use the new explicit conversion. This has been specialized in the language so that in contexts requiring a bool the conversion happens implicitly. Thus most objections should be eliminated.

Default constructor.

Constructor from bool.

Return true if states are equal.

Return true if this is empty.

Return true if this is indeterminate.

Return true if this is false or true (normal boolean).

Conversion to bool.

Bool set state.

{
namespace tr2
{
_GLIBCXX_BEGIN_NAMESPACE_VERSION

  class bool_set
  {
  public:

    constexpr bool_set() : _M_b(_S_false) { }

    constexpr bool_set(bool __t) : _M_b(_Bool_set_val(__t)) { }

    // I'm not sure about this.
    bool contains(bool_set __b) const
    { return this->is_singleton() && this->equals(__b); }

    bool equals(bool_set __b) const
    { return __b._M_b == _M_b; }

    bool is_emptyset() const
    { return _M_b == _S_empty; }

    bool is_indeterminate() const
    { return _M_b == _S_indet; }

    bool is_singleton() const
    { return _M_b == _S_false || _M_b == _S_true_; }

    //explicit
    operator bool() const
    {
      if (! is_singleton())
    throw std::bad_cast();
      return _M_b;
    }

    static bool_set indeterminate()
    {
      bool_set __b;
      __b._M_b = _S_indet;
      return __b;
    }

    static bool_set emptyset()
    {
      bool_set __b;
      __b._M_b = _S_empty;
      return __b;
    }

    friend bool_set
    operator!(bool_set __b)
    { return __b._M_not(); }

    friend bool_set
    operator^(bool_set __s, bool_set __t)
    { return __s._M_xor(__t); }

    friend bool_set
    operator|(bool_set __s, bool_set __t)
    { return __s._M_or(__t); }

    friend bool_set
    operator&(bool_set __s, bool_set __t)
    { return __s._M_and(__t); }

    friend bool_set
    operator==(bool_set __s, bool_set __t)
    { return __s._M_eq(__t); }


    //  These overloads replace the facet additions in the paper!

    template<typename CharT, typename Traits>
      friend std::basic_ostream<CharT, Traits>&
      operator<<(std::basic_ostream<CharT, Traits>& __out, bool_set __b)
      {
    int __a = __b._M_b;
    __out << __a;
      }

    template<typename CharT, typename Traits>
      friend std::basic_istream<CharT, Traits>&
      operator>>(std::basic_istream<CharT, Traits>& __in, bool_set& __b)
      {
    long __c;
    __in >> __c;
    if (__c >= _S_false && __c < _S_empty)
      __b._M_b = static_cast<_Bool_set_val>(__c);
      }

  private:

    enum _Bool_set_val: unsigned char
    {
      _S_false = 0,
      _S_true_ = 1,
      _S_indet = 2,
      _S_empty = 3
    };

    _Bool_set_val _M_b;

    bool_set(_Bool_set_val __c) : _M_b(__c) { }

    bool_set _M_not() const
    { return _S_not[this->_M_b]; }

    bool_set _M_xor(bool_set __b) const
    { return _S_xor[this->_M_b][__b._M_b]; }

    bool_set _M_or(bool_set __b) const
    { return _S_or[this->_M_b][__b._M_b]; }

    bool_set _M_and(bool_set __b) const
    { return _S_and[this->_M_b][__b._M_b]; }

    bool_set _M_eq(bool_set __b) const
    { return _S_eq[this->_M_b][__b._M_b]; }

    static _Bool_set_val _S_not[4];

    static _Bool_set_val _S_xor[4][4];

    static _Bool_set_val _S_or[4][4];

    static _Bool_set_val _S_and[4][4];

    static _Bool_set_val _S_eq[4][4];
  };

  //  20.2.3.2 bool_set values

  inline bool
  contains(bool_set __s, bool_set __t)
  { return __s.contains(__t); }

  inline bool
  equals(bool_set __s, bool_set __t)
  { return __s.equals(__t); }

  inline bool
  is_emptyset(bool_set __b)
  { return __b.is_emptyset(); }

  inline bool
  is_indeterminate(bool_set __b)
  { return __b.is_indeterminate(); }

  inline bool
  is_singleton(bool_set __b)
  { return __b.is_singleton(); }

  inline bool
  certainly(bool_set __b)
  { return ! __b.contains(false); }

  inline bool
  possibly(bool_set __b)
  { return __b.contains(true); }


  //  20.2.3.3 bool_set set operations

  inline bool_set
  set_union(bool __s, bool_set __t)
  { return bool_set(__s) | __t; }

  inline bool_set
  set_union(bool_set __s, bool __t)
  { return __s | bool_set(__t); }

  inline bool_set
  set_union(bool_set __s, bool_set __t)
  { return __s | __t; }

  inline bool_set
  set_intersection(bool __s, bool_set __t)
  { return bool_set(__s) & __t; }

  inline bool_set
  set_intersection(bool_set __s, bool __t)
  { return __s & bool_set(__t); }

  inline bool_set
  set_intersection(bool_set __s, bool_set __t)
  { return __s & __t; }

  inline bool_set
  set_complement(bool_set __b)
  { return ! __b; }


  //  20.2.3.4 bool_set logical operators

  inline bool_set
  operator^(bool __s, bool_set __t)
  { return bool_set(__s) ^ __t; }

  inline bool_set
  operator^(bool_set __s, bool __t)
  { return __s ^ bool_set(__t); }

  inline bool_set
  operator|(bool __s, bool_set __t)
  { return bool_set(__s) | __t; }

  inline bool_set
  operator|(bool_set __s, bool __t)
  { return __s | bool_set(__t); }

  inline bool_set
  operator&(bool __s, bool_set __t)
  { return bool_set(__s) & __t; }

  inline bool_set
  operator&(bool_set __s, bool __t)
  { return __s & bool_set(__t); }


  //  20.2.3.5 bool_set relational operators

  inline bool_set
  operator==(bool __s, bool_set __t)
  { return bool_set(__s) == __t; }

  inline bool_set
  operator==(bool_set __s, bool __t)
  { return __s == bool_set(__t); }

  inline bool_set
  operator!=(bool __s, bool_set __t)
  { return ! (__s == __t); }

  inline bool_set
  operator!=(bool_set __s, bool __t)
  { return ! (__s == __t); }

  inline bool_set
  operator!=(bool_set __s, bool_set __t)
  { return ! (__s == __t); }

_GLIBCXX_END_NAMESPACE_VERSION
}
}