libsigcplusplus/sigc++/adaptors/macros/hide.h.m4

dnl Copyright 2002, The libsigc++ Development Team
dnl
dnl This library is free software; you can redistribute it and/or
dnl modify it under the terms of the GNU Lesser General Public
dnl License as published by the Free Software Foundation; either
dnl version 2.1 of the License, or (at your option) any later version.
dnl
dnl This library is distributed in the hope that it will be useful,
dnl but WITHOUT ANY WARRANTY; without even the implied warranty of
dnl MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
dnl Lesser General Public License for more details.
dnl
dnl You should have received a copy of the GNU Lesser General Public
dnl License along with this library; if not, write to the Free Software
dnl Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
dnl
divert(-1)

include(template.macros.m4)

define([ORDINAL],[dnl
ifelse($1,0,,$1)ifelse($1,0,[last],$1,1,[st],$1,2,[nd],$1,3,[rd],[th])[]dnl
])
define([DEDUCE_RESULT_TYPE],[dnl
ifelse(eval($1 < 2),1,[#ifndef DOXYGEN_SHOULD_SKIP_THIS
],)dnl Only for the first two template specializations. ($1 = 0..CALL_SIZE)
  template <LOOP(class T_arg%1=void, CALL_SIZE)>
  struct deduce_result_type
ifelse($1,0,[dnl
    { typedef typename adaptor_type::template deduce_result_type<LOOP(_P_(T_arg%1),eval($2-1))>::type type; };
],[dnl
    { typedef typename adaptor_type::template deduce_result_type<LIST(LOOP(_P_(T_arg%1),eval($1-1)), FOR(eval($1+1),$2,[_P_(T_arg%1),]))>::type type; };
])dnl
ifelse(eval($1 < 2),1,[#endif // DOXYGEN_SHOULD_SKIP_THIS
],)dnl
])
define([HIDE_OPERATOR],[dnl
ifelse($2,0,,[dnl
ifelse($2,1,[dnl
  /** Invokes the wrapped functor ignoring the only argument.
   * @param _A_a1 Argument to be ignored.
   * @return The return value of the functor invocation.
   */
  template <class T_arg1>
  typename deduce_result_type<T_arg1>::type
  operator()(T_arg1)
    { return this->functor_(); }

  #ifndef SIGC_TEMPLATE_SPECIALIZATION_OPERATOR_OVERLOAD
  template <class T_arg1>
  typename deduce_result_type<T_arg1>::type
  sun_forte_workaround(T_arg1 _A_a1)
    { return this->functor_(); }
  #endif

],$1,0,[dnl
  /** Invokes the wrapped functor, ignoring the last argument.dnl
FOR(1, eval($2-1),[
   * @param _A_a%1 Argument to be passed on to the functor.])
   * @param _A_a$2 Argument to be ignored.
   * @return The return value of the functor invocation.
   */
  template <LOOP([class T_arg%1], $2)>
  typename deduce_result_type<LOOP(T_arg%1, $2)>::type
  operator()(LOOP(T_arg%1 _A_a%1, eval($2-1)), T_arg$2)
    { return this->functor_.SIGC_WORKAROUND_OPERATOR_PARENTHESES<LIST(FOR(1,eval($2-1),[_P_(T_arg%1),]))>
        (LIST(FOR(1,eval($2-1),[_A_a%1,]))); }

  #ifndef SIGC_TEMPLATE_SPECIALIZATION_OPERATOR_OVERLOAD
  template <LOOP([class T_arg%1], $2)>
  typename deduce_result_type<LOOP(T_arg%1, $2)>::type
  sun_forte_workaround(LOOP(T_arg%1 _A_a%1, eval($2-1)), T_arg$2)
    { return this->functor_.SIGC_WORKAROUND_OPERATOR_PARENTHESES<LIST(FOR(1,eval($2-1),[_P_(T_arg%1),]))>
        (LIST(FOR(1,eval($2-1),[_A_a%1,]))); }
  #endif

],[dnl
  /** Invokes the wrapped functor, ignoring the ORDINAL($1) argument.dnl
FOR(1, eval($1-1),[
   * @param _A_a%1 Argument to be passed on to the functor.])
   * @param _A_a$1 Argument to be ignored.dnl
FOR(eval($1+1), $2,[
   * @param _A_a%1 Argument to be passed on to the functor.])
   * @return The return value of the functor invocation.
   */
  template <LOOP([class T_arg%1], $2)>
  typename deduce_result_type<LOOP(T_arg%1, $2)>::type
  operator()(LIST(FOR(1,eval($1-1),[T_arg%1 _A_a%1,]),T_arg$1,FOR(eval($1+1),$2,[T_arg%1 _A_a%1,])))
    { return this->functor_.SIGC_WORKAROUND_OPERATOR_PARENTHESES<LIST(FOR(1,eval($1-1),[_P_(T_arg%1),]),FOR(eval($1+1), $2,[_P_(T_arg%1),]))>
        (LIST(FOR(1,eval($1-1),[_A_a%1,]),FOR(eval($1+1),$2,[_A_a%1,]))); }

  #ifndef SIGC_TEMPLATE_SPECIALIZATION_OPERATOR_OVERLOAD
  template <LOOP([class T_arg%1], $2)>
  typename deduce_result_type<LOOP(T_arg%1, $2)>::type
  sun_forte_workaround(LIST(FOR(1,eval($1-1),[T_arg%1 _A_a%1,]),T_arg$1,FOR(eval($1+1),$2,[T_arg%1 _A_a%1,])))
    { return this->functor_.SIGC_WORKAROUND_OPERATOR_PARENTHESES<LIST(FOR(1,eval($1-1),[_P_(T_arg%1),]),FOR(eval($1+1), $2,[_P_(T_arg%1),]))>
        (LIST(FOR(1,eval($1-1),[_A_a%1,]),FOR(eval($1+1),$2,[_A_a%1,]))); }
  #endif

])])dnl
])dnl end HIDE_OPERATOR

define([HIDE_FUNCTOR],[dnl
ifelse($1,1,[#ifndef DOXYGEN_SHOULD_SKIP_THIS
],)dnl Include only the first two template specializations in the documentation. ($1 = -1..CALL_SIZE-1)
/** Adaptor that adds a dummy parameter to the wrapped functor.
 * This template specialization ignores the value of the ORDINAL(eval($1+1)) parameter in operator()().
 *
 * @ingroup hide
 */
template <class T_functor>
struct hide_functor <$1, T_functor> : public adapts<T_functor>
{
  typedef typename adapts<T_functor>::adaptor_type adaptor_type;

DEDUCE_RESULT_TYPE(eval($1+1),CALL_SIZE)dnl
  typedef typename adaptor_type::result_type  result_type;

FOR(eval($1+1),CALL_SIZE,[[HIDE_OPERATOR(eval($1+1),%1)]])dnl

  /** Constructs a hide_functor object that adds a dummy parameter to the passed functor.
   * @param _A_func Functor to invoke from operator()().
   */
  explicit hide_functor(const T_functor& _A_func)
    : adapts<T_functor>(_A_func)
    {}
};
ifelse($1,eval(CALL_SIZE-1),[#endif // DOXYGEN_SHOULD_SKIP_THIS
],)dnl Include only the first two template specializations in the documentation. ($1 = -1..CALL_SIZE-1)

])dnl end HIDE_FUNCTOR

divert(0)dnl
_FIREWALL([ADAPTORS_HIDE])
#include <sigc++/adaptors/adaptor_trait.h>

namespace sigc {

/** @defgroup hide hide(), hide_return()
 * sigc::hide() alters an arbitrary functor in that it adds a parameter
 * whose value is ignored on invocation of the returned functor.
 * Thus you can discard one argument of a signal.
 *
 * You may optionally specify the zero-based position of the parameter
 * to ignore as a template argument. The default is to ignore the last
 * parameter.
 * (A value of @p -1 adds a parameter at the end so sigc::hide<-1>() gives the same result as sigc::hide().)
 *
 * The type of the parameter can optionally be specified if not deduced.
 *
 * @par Examples:
 * @code
 * void foo(int, int);
 * // single argument hiding ...
 * sigc::hide(&foo)(1,2,3);     // adds a dummy parameter at the back and calls foo(1,2)
 * sigc::hide<-1>(&foo)(1,2,3); // same as sigc::hide(&foo)(1,2,3) (calls foo(1,2))
 * sigc::hide<0>(&foo)(1,2,3);  // adds a dummy parameter at the beginning and calls foo(2,3)
 * sigc::hide<1>(&foo)(1,2,3);  // adds a dummy parameter in the middle and calls foo(1,3)
 * sigc::hide<2>(&foo)(1,2,3);  // adds a dummy parameter at the back and calls foo(1,2)
 * @endcode
 *
 * The functor sigc::hide() returns can be directly passed into
 * sigc::signal::connect().
 *
 * @par Example:
 * @code
 * sigc::signal<void,int> some_signal;
 * void foo();
 * some_signal.connect(sigc::hide(&foo));
 * @endcode
 *
 * sigc::hide() can be nested in order to discard multiple arguments.
 * @par Example:
 * @code
 * // multiple argument hiding ...
 * sigc::hide(sigc::hide(&foo))(1,2,3,4); // adds two dummy parameters at the back and calls foo(1,2)
 * @endcode

 * sigc::hide_return() alters an arbitrary functor by
 * dropping its return value, thus converting it to a void functor.
 *
 * @ingroup adaptors
 */

/** Adaptor that adds a dummy parameter to the wrapped functor.
 * Use the convenience function sigc::hide() to create an instance of sigc::hide_functor.
 *
 * The following template arguments are used:
 * - @e I_location Zero-based position of the dummy parameter (@p -1 for the last parameter).
 * - @e T_type Type of the dummy parameter.
 * - @e T_functor Type of the functor to wrap.
 *
 * @ingroup hide
 */
template <int I_location, class T_functor>
#ifndef DOXYGEN_SHOULD_SKIP_THIS
struct hide_functor;
#else
struct hide_functor {};
#endif

FOR(-1,eval(CALL_SIZE-1),[[HIDE_FUNCTOR(%1)]])dnl

#ifndef DOXYGEN_SHOULD_SKIP_THIS
//template specialization of visitor<>::do_visit_each<>(action, functor):
/** Performs a functor on each of the targets of a functor.
 * The function overload for sigc::hide_functor performs a functor on the
 * functor stored in the sigc::hide_functor object.
 *
 * @ingroup hide
 */
template <int I_location, class T_functor>
struct visitor<hide_functor<I_location, T_functor> >
{
  template <typename T_action>
  static void do_visit_each(const T_action& _A_action,
                            const hide_functor<I_location, T_functor>& _A_target)
  {
    sigc::visit_each(_A_action, _A_target.functor_);
  }
};
#endif // DOXYGEN_SHOULD_SKIP_THIS

/** Creates an adaptor of type sigc::hide_functor which adds a dummy parameter to the passed functor.
 * The optional template argument @e I_location specifies the zero-based
 * position of the dummy parameter in the returned functor (@p -1 stands for the last parameter).
 *
 * @param _A_func Functor that should be wrapped.
 * @return Adaptor that executes @e _A_func, ignoring the value of the dummy parameter.
 *
 * @ingroup hide
 */
template <int I_location, class T_functor>
inline hide_functor<I_location, T_functor>
hide(const T_functor& _A_func)
  { return hide_functor<I_location, T_functor>(_A_func); }

/** Creates an adaptor of type sigc::hide_functor which adds a dummy parameter to the passed functor.
 * This overload adds a dummy parameter at the back of the functor's parameter list.
 *
 * @param _A_func Functor that should be wrapped.
 * @return Adaptor that executes @e _A_func, ignoring the value of the last parameter.
 *
 * @ingroup hide
 */
template <class T_functor>
inline hide_functor<-1, T_functor>
hide(const T_functor& _A_func)
  { return hide_functor<-1, T_functor> (_A_func); }

} /* namespace sigc */