named_params.hpp 11.3 KB
Newer Older
xuebingbing's avatar
xuebingbing committed
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298 299 300 301 302 303 304 305 306 307 308 309 310 311 312 313 314 315 316 317 318 319 320 321 322 323 324 325 326 327 328 329
//  (C) Copyright Gennadiy Rozental 2005-2008.
//  Distributed under the Boost Software License, Version 1.0.
//  (See accompanying file LICENSE_1_0.txt or copy at 
//  http://www.boost.org/LICENSE_1_0.txt)

//  See http://www.boost.org/libs/test for the library home page.
//
//  File        : $RCSfile$
//
//  Version     : $Revision$
//
//  Description : facilities for named function parameters support
// ***************************************************************************

#ifndef BOOST_TEST_NAMED_PARAM_022505GER
#define BOOST_TEST_NAMED_PARAM_022505GER

// Boost
#include <boost/config.hpp>
#include <boost/detail/workaround.hpp>

// Boost.Test
#include <boost/test/utils/rtti.hpp>
#include <boost/test/utils/assign_op.hpp>

#include <boost/type_traits/remove_reference.hpp>

#include <boost/test/detail/suppress_warnings.hpp>

//____________________________________________________________________________//

namespace boost {

namespace nfp { // named function parameters

// ************************************************************************** //
// **************              forward declarations            ************** //
// ************************************************************************** //

template<typename T, typename unique_id,typename RefType>   struct named_parameter;
template<typename unique_id,bool required>                  struct keyword;

namespace nfp_detail {

template<typename NP1,typename NP2>        struct named_parameter_combine;

// ************************************************************************** //
// **************          access_to_invalid_parameter         ************** //
// ************************************************************************** //

struct access_to_invalid_parameter {};

//____________________________________________________________________________//

inline void 
report_access_to_invalid_parameter()
{
    throw access_to_invalid_parameter();
}

//____________________________________________________________________________//

// ************************************************************************** //
// **************                       nil                    ************** //
// ************************************************************************** //

struct nil {
    template<typename T>
#if defined(__GNUC__) || defined(__HP_aCC) || defined(__EDG__) || defined(__SUNPRO_CC)
    operator T() const
#else
    operator T const&() const
#endif
    { report_access_to_invalid_parameter(); static T* v = 0; return *v; }

    template<typename T>
    T any_cast() const
    { report_access_to_invalid_parameter(); static typename remove_reference<T>::type* v = 0; return *v; }

    template<typename Arg1>
    nil operator()( Arg1 const& )
    { report_access_to_invalid_parameter(); return nil(); }

    template<typename Arg1,typename Arg2>
    nil operator()( Arg1 const&, Arg2 const& )
    { report_access_to_invalid_parameter(); return nil(); }

    template<typename Arg1,typename Arg2,typename Arg3>
    nil operator()( Arg1 const&, Arg2 const&, Arg3 const& )
    { report_access_to_invalid_parameter(); return nil(); }

    // Visitation support
    template<typename Visitor>
    void            apply_to( Visitor& V ) const {}

    static nil&     inst() { static nil s_inst; return s_inst; }
private:
    nil() {}
};
    
// ************************************************************************** //
// **************              named_parameter_base            ************** //
// ************************************************************************** //

template<typename Derived>
struct named_parameter_base {
    template<typename NP>
    named_parameter_combine<NP,Derived>
    operator,( NP const& np ) const { return named_parameter_combine<NP,Derived>( np, *static_cast<Derived const*>(this) ); }
};

//____________________________________________________________________________//

// ************************************************************************** //
// **************             named_parameter_combine          ************** //
// ************************************************************************** //

template<typename NP, typename Rest = nil>
struct named_parameter_combine 
: Rest
, named_parameter_base<named_parameter_combine<NP,Rest> > {
    typedef typename NP::ref_type  res_type;
    typedef named_parameter_combine<NP,Rest> self_type;

    // Constructor
    named_parameter_combine( NP const& np, Rest const& r )
    : Rest( r )
    , m_param( np )
    {}

    // Access methods
    res_type    operator[]( keyword<typename NP::id,true> kw ) const    { return m_param[kw]; }
    res_type    operator[]( keyword<typename NP::id,false> kw ) const   { return m_param[kw]; }
    using       Rest::operator[];

    bool        has( keyword<typename NP::id,false> kw ) const          { return m_param.has( kw ); }
    using       Rest::has;

    void        erase( keyword<typename NP::id,false> kw ) const        { m_param.erase( kw ); }
    using       Rest::erase;

#if BOOST_WORKAROUND(__MWERKS__, BOOST_TESTED_AT(0x3206)) || \
    BOOST_WORKAROUND(__BORLANDC__, BOOST_TESTED_AT(0x0610))
    template<typename NP>
    named_parameter_combine<NP,self_type> operator,( NP const& np ) const
    { return named_parameter_combine<NP,self_type>( np, *this ); }
#else
    using       named_parameter_base<named_parameter_combine<NP,Rest> >::operator,;
#endif

    // Visitation support
    template<typename Visitor>
    void            apply_to( Visitor& V ) const
    {
        m_param.apply_to( V );

        Rest::apply_to( V );
    }
private:
    // Data members
    NP          m_param;
};

} // namespace nfp_detail

// ************************************************************************** //
// **************                 named_parameter              ************** //
// ************************************************************************** //

template<typename T, typename unique_id,typename ReferenceType=T&>
struct named_parameter
: nfp_detail::named_parameter_base<named_parameter<T, unique_id,ReferenceType> >
{
    typedef nfp_detail::nil nil_t;
    typedef T               data_type;
    typedef ReferenceType   ref_type;
    typedef unique_id       id;

    // Constructor
    explicit        named_parameter( ref_type v ) 
    : m_value( v )
    , m_erased( false )
    {}
    named_parameter( named_parameter const& np )
    : m_value( np.m_value )
    , m_erased( np.m_erased )
    {}

    // Access methods
    ref_type        operator[]( keyword<unique_id,true> ) const     { return m_erased ? nil_t::inst().template any_cast<ref_type>() :  m_value; }
    ref_type        operator[]( keyword<unique_id,false> ) const    { return m_erased ? nil_t::inst().template any_cast<ref_type>() :  m_value; }
    template<typename UnknownId>
    nil_t           operator[]( keyword<UnknownId,false> ) const    { return nil_t::inst(); }

    bool            has( keyword<unique_id,false> ) const           { return !m_erased; }
    template<typename UnknownId>
    bool            has( keyword<UnknownId,false> ) const           { return false; }

    void            erase( keyword<unique_id,false> ) const         { m_erased = true; }
    template<typename UnknownId>
    void            erase( keyword<UnknownId,false> ) const         {}

    // Visitation support
    template<typename Visitor>
    void            apply_to( Visitor& V ) const
    {
        V.set_parameter( rtti::type_id<unique_id>(), m_value );
    }

private:
    // Data members
    ref_type        m_value;
    mutable bool    m_erased;
};

//____________________________________________________________________________//

// ************************************************************************** //
// **************                    no_params                 ************** //
// ************************************************************************** //

namespace nfp_detail {
typedef named_parameter<char, struct no_params_type_t,char> no_params_type;
} // namespace nfp_detail

namespace {
nfp_detail::no_params_type no_params( '\0' );
} // local namespace

//____________________________________________________________________________//

// ************************************************************************** //
// **************                     keyword                  ************** //
// ************************************************************************** //

template<typename unique_id, bool required = false>
struct keyword {
    typedef unique_id id;

    template<typename T>
    named_parameter<T const,unique_id>
    operator=( T const& t ) const       { return named_parameter<T const,unique_id>( t ); }

    template<typename T>
    named_parameter<T,unique_id>
    operator=( T& t ) const   { return named_parameter<T,unique_id>( t ); }

    named_parameter<char const*,unique_id,char const*>
    operator=( char const* t ) const   { return named_parameter<char const*,unique_id,char const*>( t ); }
};

//____________________________________________________________________________//

// ************************************************************************** //
// **************                  typed_keyword               ************** //
// ************************************************************************** //

template<typename T, typename unique_id, bool required = false>
struct typed_keyword : keyword<unique_id,required> {
    named_parameter<T const,unique_id>
    operator=( T const& t ) const       { return named_parameter<T const,unique_id>( t ); }

    named_parameter<T,unique_id>
    operator=( T& t ) const             { return named_parameter<T,unique_id>( t ); }
};

//____________________________________________________________________________//

template<typename unique_id>
struct typed_keyword<bool,unique_id,false>
: keyword<unique_id,false>
, named_parameter<bool,unique_id,bool> {
    typedef unique_id id;

    typed_keyword() : named_parameter<bool,unique_id,bool>( true ) {}

    named_parameter<bool,unique_id,bool>
    operator!() const           { return named_parameter<bool,unique_id,bool>( false ); }
};

//____________________________________________________________________________//

// ************************************************************************** //
// **************                optionally_assign             ************** //
// ************************************************************************** //

template<typename T>
inline void
optionally_assign( T&, nfp_detail::nil )
{
    nfp_detail::report_access_to_invalid_parameter();
}

//____________________________________________________________________________//

template<typename T, typename Source>
inline void
#if BOOST_WORKAROUND( __MWERKS__, BOOST_TESTED_AT( 0x3003 ) ) \
    || BOOST_WORKAROUND( __DECCXX_VER, BOOST_TESTED_AT(60590042) )
optionally_assign( T& target, Source src )
#else
optionally_assign( T& target, Source const& src )
#endif
{
    using namespace unit_test;

    assign_op( target, src, static_cast<int>(0) );
}

//____________________________________________________________________________//

template<typename T, typename Params, typename Keyword>
inline void
optionally_assign( T& target, Params const& p, Keyword k )
{
    if( p.has(k) )
        optionally_assign( target, p[k] );
}

//____________________________________________________________________________//

} // namespace nfp

} // namespace boost

#include <boost/test/detail/enable_warnings.hpp>

#endif // BOOST_TEST_NAMED_PARAM_022505GER