1234567891011121314151617181920212223242526272829303132333435363738394041424344454647484950515253545556575859606162636465666768697071727374757677787980818283848586878889909192939495969798991001011021031041051061071081091101111121131141151161171181191201211221231241251261271281291301311321331341351361371381391401411421431441451461471481491501511521531541551561571581591601611621631641651661671681691701711721731741751761771781791801811821831841851861871881891901911921931941951961971981992002012022032042052062072082092102112122132142152162172182192202212222232242252262272282292302312322332342352362372382392402412422432442452462472482492502512522532542552562572582592602612622632642652662672682692702712722732742752762772782792802812822832842852862872882892902912922932942952962972982993003013023033043053063073083093103113123133143153163173183193203213223233243253263273283293303313323333343353363373383393403413423433443453463473483493503513523533543553563573583593603613623633643653663673683693703713723733743753763773783793803813823833843853863873883893903913923933943953963973983994004014024034044054064074084094104114124134144154164174184194204214224234244254264274284294304314324334344354364374384394404414424434444454464474484494504514524534544554564574584594604614624634644654664674684694704714724734744754764774784794804814824834844854864874884894904914924934944954964974984995005015025035045055065075085095105115125135145155165175185195205215225235245255265275285295305315325335345355365375385395405415425435445455465475485495505515525535545555565575585595605615625635645655665675685695705715725735745755765775785795805815825835845855865875885895905915925935945955965975985996006016026036046056066076086096106116126136146156166176186196206216226236246256266276286296306316326336346356366376386396406416426436446456466476486496506516526536546556566576586596606616626636646656666676686696706716726736746756766776786796806816826836846856866876886896906916926936946956966976986997007017027037047057067077087097107117127137147157167177187197207217227237247257267277287297307317327337347357367377387397407417427437447457467477487497507517527537547557567577587597607617627637647657667677687697707717727737747757767777787797807817827837847857867877887897907917927937947957967977987998008018028038048058068078088098108118128138148158168178188198208218228238248258268278288298308318328338348358368378388398408418428438448458468478488498508518528538548558568578588598608618628638648658668678688698708718728738748758768778788798808818828838848858868878888898908918928938948958968978988999009019029039049059069079089099109119129139149159169179189199209219229239249259269279289299309319329339349359369379389399409419429439449459469479489499509519529539549559569579589599609619629639649659669679689699709719729739749759769779789799809819829839849859869879889899909919929939949959969979989991000100110021003100410051006100710081009101010111012101310141015101610171018101910201021102210231024102510261027102810291030103110321033103410351036103710381039104010411042104310441045104610471048104910501051105210531054105510561057105810591060106110621063106410651066106710681069107010711072107310741075107610771078107910801081108210831084108510861087108810891090109110921093109410951096109710981099110011011102110311041105110611071108110911101111111211131114111511161117111811191120112111221123112411251126112711281129113011311132113311341135113611371138113911401141114211431144114511461147114811491150115111521153115411551156115711581159116011611162116311641165116611671168116911701171117211731174117511761177117811791180118111821183118411851186118711881189119011911192119311941195119611971198119912001201120212031204120512061207120812091210121112121213121412151216121712181219122012211222122312241225122612271228122912301231123212331234123512361237123812391240124112421243124412451246124712481249125012511252125312541255125612571258125912601261126212631264126512661267126812691270127112721273127412751276127712781279128012811282128312841285128612871288128912901291129212931294129512961297129812991300130113021303130413051306130713081309131013111312131313141315131613171318131913201321132213231324132513261327132813291330133113321333133413351336133713381339134013411342134313441345134613471348134913501351135213531354135513561357135813591360136113621363136413651366136713681369137013711372137313741375137613771378137913801381138213831384138513861387138813891390139113921393139413951396139713981399140014011402 |
- [/==============================================================================
- Copyright (C) 2006 Tobias Schwinger
- Use, modification and distribution is subject to 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)
- ===============================================================================/]
- [section Functional]
- Components to call functions and function objects and to make Fusion code
- callable through a function object interface.
- [heading Header]
- #include <boost/fusion/functional.hpp>
- [heading Fused and unfused forms]
- What is a function call?
- f (a,b,c)
- It is a name and a tuple written next to each other, left-to-right.
- Although the C++ syntax does not allow to replace [^(a,b,c)] with some Fusion
- __sequence__, introducing yet another function provides a solution:
- invoke(f,my_sequence)
- Alternatively it is possible to apply a simple transformation to [^f] in order
- to achieve the same effect:
- f tuple <=> ``f'`` (tuple)
- Now, [^f'] is an unary function that takes the arguments to `f` as a tuple;
- [^f'] is the /fused/ form of `f`.
- Reading the above equivalence right-to-left to get the inverse transformation,
- `f` is the /unfused/ form of [^f'].
- [heading Calling functions and function objects]
- Having generic C++ code call back arbitrary functions provided by the client
- used to be a heavily repetitive task, as different functions can differ in
- arity, invocation syntax and other properties that might be part of the type.
- Transporting arguments as Fusion sequences and factoring out the invocation
- makes Fusion algorithms applicable to function arguments and also reduces
- the problem to one invocation syntax and a fixed arity (instead of an arbitrary
- number of arbitrary arguments times several syntactic variants times additional
- properties).
- Transforming an unfused function into its fused counterpart allows n-ary
- calls from an algorithm that invokes an unary __poly_func_obj__ with
- __sequence__ arguments.
- The library provides several function templates to invoke different kinds of
- functions and adapters to transform them into fused form, respectively.
- Every variant has a corresponding generator function template that returns
- an adapter instance for the given argument.
- Constructors can be called applying __boost_func_factory__.
- [heading Making Fusion code callable through a function object interface]
- Transforming a fused function into its unfused counterpart allows to create
- function objects to accept arbitrary calls. In other words, an unary function
- object can be implemented instead of (maybe heavily overloaded) function
- templates or function call operators.
- The library provides both a strictly typed and a generic variant for this
- transformation. The latter should be used in combination with
- __boost_func_forward__ to attack __the_forwarding_problem__.
- Both variants have a corresponding generator function template that returns an
- adapter instance for the given argument.
- [/ ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ ]
- [section Concepts]
- [section:callable Callable Object]
- [heading Description]
- A pointer to a function, a pointer to member function, a pointer to member
- data, or a class type whose objects can appear immediately to the left of a
- function call operator.
- [heading Models]
- * function pointer types
- * member (function or data) pointer types
- * all kinds of function objects
- [heading Examples]
- & a_free_function
- & a_class::a_static_member_function
- & a_class::a_nonstatic_data_member
- & a_class::a_nonstatic_member_function
- std::less<int>()
- // using namespace boost;
- bind(std::less<int>(), _1, 5)
- lambda::_1 += lambda::_2;
- fusion::__make_fused_function_object__(std::less<int>())
- [endsect]
- [section:reg_callable Regular Callable Object]
- [heading Description]
- A non-member-pointer __callable_obj__ type: A pointer to a function or a class
- type whose objects can appear immediately to the left of a function call operator.
- [heading Refinement of]
- * __callable_obj__
- [variablelist Notation
- [[`F`][A possibly const qualified Deferred Callable Object type]]
- [[`f`][An object or reference to an object of type F]]
- [[`A1 ...AN`][Argument types]]
- [[`a1 ...aN`][Objects or references to objects with types `A1 ...AN`]]
- ]
- [heading Expression requirements]
- [table
- [[Expression][Return Type][Runtime Complexity]]
- [[`f(a1, ...aN)`][Unspecified][Unspecified]]
- ]
- [heading Models]
- * function pointer types
- * all kinds of function objects
- [heading Examples]
- & a_free_function
- & a_class::a_static_member_function
- std::less<int>()
- // using namespace boost;
- bind(std::less<int>(), _1, 5)
- lambda::_1 += lambda::_2;
- fusion::__make_fused_function_object__(std::less<int>())
- [endsect]
- [section:def_callable Deferred Callable Object]
- [heading Description]
- __callable_obj__ types that work with __boost_result_of__ to determine the
- result of a call.
- [heading Refinement of]
- * __callable_obj__
- [blurb note Once C++ supports the [^decltype] keyword, all models of
- __callable_obj__ will also be models of __def_callable_obj__, because
- function objects won't need client-side support for `result_of`.
- ]
- [variablelist Notation
- [[`F`][A possibly const qualified Deferred Callable Object type]]
- [[`A1 ...AN`][Argument types]]
- [[`a1 ...aN`][Objects or references to objects with types `A1 ...AN`]]
- [[`T1 ...TN`][`T`i is `A`i `&` if `a`i is an __lvalue__, same as `A`i, otherwise]]
- ]
- [heading Expression requirements]
- [table
- [[Expression][Type]]
- [[__boost_result_of_call__`< F(T1 ...TN) >::type`][Result of a call with `A1 ...AN`-typed arguments]]
- ]
- [heading Models]
- * __poly_func_obj__ types
- * member (function or data) pointer types
- [heading Examples]
- & a_free_function
- & a_class::a_static_member_function
- & a_class::a_nonstatic_data_member
- & a_class::a_nonstatic_member_function
- std::less<int>()
- // using namespace boost;
- bind(std::less<int>(), _1, 5)
- // Note: Boost.Lambda expressions don't work with __boost_result_of__
- fusion::__make_fused_function_object__(std::less<int>())
- [endsect]
- [section:poly Polymorphic Function Object]
- [heading Description]
- A non-member-pointer __def_callable_obj__ type.
- [heading Refinement of]
- * __reg_callable_obj__
- * __def_callable_obj__
- [variablelist Notation
- [[`F`][A possibly const-qualified Polymorphic Function Object type]]
- [[`f`][An object or reference to an object of type F]]
- [[`A1 ...AN`][Argument types]]
- [[`a1 ...aN`][Objects or references to objects with types `A1 ...AN`]]
- [[`T1 ...TN`][`T`i is `A`i `&` if `a`i is an __lvalue__, same as `A`i, otherwise]]
- ]
- [heading Expression requirements]
- [table
- [[Expression][Return Type][Runtime Complexity]]
- [[`f(a1, ...aN)`][`result_of< F(T1, ...TN) >::type`][Unspecified]]
- ]
- [heading Models]
- * function pointers
- * function objects of the Standard Library
- * all Fusion __functional_adapters__
- [heading Examples]
- & a_free_function
- & a_class::a_static_member_function
- std::less<int>()
- // using namespace boost;
- bind(std::less<int>(), _1, 5)
- // Note: Boost.Lambda expressions don't work with __boost_result_of__
- fusion::__make_fused_function_object__(std::less<int>())
- [endsect]
- [endsect]
- [/ ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ ]
- [section Invocation]
- [section Functions]
- [section invoke]
- [heading Description]
- Calls a __def_callable_obj__ with the arguments from a __sequence__.
- The first template parameter can be specialized explicitly to avoid copying
- and/or to control the const qualification of a function object.
- If the target function is a pointer to a class members, the corresponding
- object can be specified as a reference, pointer, or smart pointer.
- In case of the latter, a freestanding [^get_pointer] function must be
- defined (Boost provides this function for [^std::auto_ptr] and
- __boost_shared_ptr_call__).
- Constructors can be called applying __boost_func_factory__.
- [heading Synopsis]
- template<
- typename Function,
- class Sequence
- >
- typename __result_of_invoke__<Function, Sequence>::type
- invoke(Function f, Sequence & s);
- template<
- typename Function,
- class Sequence
- >
- typename __result_of_invoke__<Function, Sequence const>::type
- invoke(Function f, Sequence const & s);
- [heading Parameters]
- [table
- [[Parameter] [Requirement] [Description]]
- [[`f`] [A __def_callable_obj__] [The function to call.]]
- [[`s`] [A __forward_sequence__] [The arguments.]]
- ]
- [heading Expression Semantics]
- invoke(f,s);
- [*Return type]: Return type of `f` when invoked with the elements in `s` as its
- arguments.
- [*Semantics]: Invokes `f` with the elements in `s` as arguments and returns
- the result of the call expression.
- [heading Header]
- #include <boost/fusion/functional/invocation/invoke.hpp>
- [heading Example]
- __std_plus_doc__<int> add;
- assert(invoke(add,__make_vector__(1,1)) == 2);
- [heading See also]
- * __invoke_procedure__
- * __invoke_function_object__
- * __result_of_invoke__
- * __fused__
- * __make_fused__
- [endsect]
- [section:invoke_proc invoke_procedure]
- [heading Description]
- Calls a __callable_obj__ with the arguments from a __sequence__. The result
- of the call is ignored.
- The first template parameter can be specialized explicitly to avoid copying
- and/or to control the const qualification of a function object.
- For pointers to class members corresponding object can be specified as
- a reference, pointer, or smart pointer. In case of the latter, a freestanding
- [^get_pointer] function must be defined (Boost provides this function for
- [^std::auto_ptr] and __boost_shared_ptr_call__).
- The target function must not be a pointer to a member object (dereferencing
- such a pointer without returning anything does not make sense, so it isn't
- implemented).
- [heading Synopsis]
- template<
- typename Function,
- class Sequence
- >
- typename __result_of_invoke_procedure__<Function, Sequence>::type
- invoke_procedure(Function f, Sequence & s);
- template<
- typename Function,
- class Sequence
- >
- typename __result_of_invoke_procedure__<Function, Sequence const>::type
- invoke_procedure(Function f, Sequence const & s);
- [heading Parameters]
- [table
- [[Parameter] [Requirement] [Description]]
- [[`f`] [Model of __callable_obj__] [The function to call.]]
- [[`s`] [Model of __forward_sequence__] [The arguments.]]
- ]
- [heading Expression Semantics]
- invoke_procedure(f,s);
- [*Return type]: `void`
- [*Semantics]: Invokes `f` with the elements in `s` as arguments.
- [heading Header]
- #include <boost/fusion/functional/invocation/invoke_procedure.hpp>
- [heading Example]
- __vector__<int,int> v(1,2);
- using namespace boost::lambda;
- invoke_procedure(_1 += _2, v);
- assert(__front__(v) == 3);
- [heading See also]
- * __invoke__
- * __invoke_function_object__
- * __result_of_invoke_procedure__
- * __fused_procedure__
- * __make_fused_procedure__
- [endsect]
- [section:invoke_fobj invoke_function_object]
- [heading Description]
- Calls a __poly_func_obj__ with the arguments from a __sequence__.
- The first template parameter can be specialized explicitly to avoid copying
- and/or to control the const qualification of a function object.
- Constructors can be called applying __boost_func_factory__.
- [heading Synopsis]
- template<
- typename Function,
- class Sequence
- >
- typename __result_of_invoke_function_object__<Function, Sequence>::type
- invoke_function_object(Function f, Sequence & s);
- template<
- typename Function,
- class Sequence
- >
- typename __result_of_invoke_function_object__<Function, Sequence const>::type
- invoke_function_object(Function f, Sequence const & s);
- [heading Parameters]
- [table
- [[Parameter] [Requirement] [Description]]
- [[`f`] [Model of __poly_func_obj__] [The function object to call.]]
- [[`s`] [Model of __forward_sequence__] [The arguments.]]
- ]
- [heading Expression Semantics]
- invoke_function_object(f,s);
- [*Return type]: Return type of `f` when invoked with the elements in `s` as its
- arguments.
- [*Semantics]: Invokes `f` with the elements in `s` as arguments and returns the
- result of the call expression.
- [heading Header]
- #include <boost/fusion/functional/invocation/invoke_function_object.hpp>
- [heading Example]
- struct sub
- {
- template <typename Sig>
- struct result;
- template <class Self, typename T>
- struct result< Self(T,T) >
- { typedef typename remove_reference<T>::type type; };
- template<typename T>
- T operator()(T lhs, T rhs) const
- {
- return lhs - rhs;
- }
- };
- void try_it()
- {
- sub f;
- assert(f(2,1) == invoke_function_object(f,__make_vector__(2,1)));
- }
- [heading See also]
- * __invoke__
- * __invoke_procedure__
- * __result_of_invoke_function_object__
- * __fused_function_object__
- * __make_fused_function_object__
- [endsect]
- [endsect] [/ Functions]
- [section Metafunctions]
- [section invoke]
- [heading Description]
- Returns the result type of __invoke__.
- [heading Synopsis]
- namespace result_of
- {
- template<
- typename Function,
- class Sequence
- >
- struct invoke
- {
- typedef __unspecified__ type;
- };
- }
- [heading See also]
- * __invoke__
- * __fused__
- [endsect]
- [section:invoke_proc invoke_procedure]
- [heading Description]
- Returns the result type of __invoke_procedure__.
- [heading Synopsis]
- namespace result_of
- {
- template<
- typename Function,
- class Sequence
- >
- struct invoke_procedure
- {
- typedef __unspecified__ type;
- };
- }
- [heading See also]
- * __invoke_procedure__
- * __fused_procedure__
- [endsect]
- [section:invoke_fobj invoke_function_object]
- [heading Description]
- Returns the result type of __invoke_function_object__.
- [heading Synopsis]
- namespace result_of
- {
- template<
- class Function,
- class Sequence
- >
- struct invoke_function_object
- {
- typedef __unspecified__ type;
- };
- }
- [heading See also]
- * __invoke_function_object__
- * __fused_function_object__
- [endsect]
- [endsect] [/ Metafunctions ]
- [section Limits]
- [heading Header]
- #include <boost/fusion/functional/invocation/limits.hpp>
- [heading Macros]
- The following macros can be defined to change the maximum arity.
- The default is 6.
- * BOOST_FUSION_INVOKE_MAX_ARITY
- * BOOST_FUSION_INVOKE_PROCEDURE_MAX_ARITY
- * BOOST_FUSION_INVOKE_FUNCTION_OBJECT_MAX_ARITY
- [endsect]
- [endsect] [/ Invocation ]
- [/ ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ ]
- [section:adapters Adapters]
- Function object templates to transform a particular target function.
- [section fused]
- [heading Description]
- An unary __poly_func_obj__ adapter template for __def_callable_obj__ target
- functions. It takes a __forward_sequence__ that contains the arguments for the
- target function.
- The type of the target function is allowed to be const qualified or a
- reference. Const qualification is preserved and propagated appropriately
- (in other words, only const versions of [^operator()] can be used for a
- target function object that is const or, if the target function object
- is held by value, the adapter is const - these semantics have nothing to
- do with the const qualification of a member function, which is referring
- to the type of object pointed to by [^this] which is specified with the
- first element in the sequence passed to the adapter).
- If the target function is a pointer to a class members, the corresponding
- object can be specified as a reference, pointer, or smart pointer.
- In case of the latter, a freestanding [^get_pointer] function must be
- defined (Boost provides this function for [^std::auto_ptr] and
- __boost_shared_ptr_call__).
- [heading Header]
- #include <boost/fusion/functional/adapter/fused.hpp>
- [heading Synopsis]
- template <typename Function>
- class fused;
- [heading Template parameters]
- [table
- [[Parameter] [Description] [Default]]
- [[`Function`] [A __def_callable_obj__] []]
- ]
- [heading Model of]
- * __poly_func_obj__
- * __def_callable_obj__
- [variablelist Notation
- [[`R`] [A possibly const qualified __def_callable_obj__ type or reference type thereof]]
- [[`r`] [An object convertible to `R`]]
- [[`s`] [A __sequence__ of arguments that are accepted by `r`]]
- [[`f`] [An instance of `fused<R>`]]
- ]
- [heading Expression Semantics]
- [table
- [[Expression] [Semantics]]
- [[`fused<R>(r)`] [Creates a fused function as described above, initializes the target function with `r`.]]
- [[`fused<R>()`] [Creates a fused function as described above, attempts to use `R`'s default constructor.]]
- [[`f(s)`] [Calls `r` with the elements in `s` as its arguments.]]
- ]
- [heading Example]
- fused< __std_plus_doc__<long> > f;
- assert(f(__make_vector__(1,2l)) == 3l);
- [heading See also]
- * __fused_procedure__
- * __fused_function_object__
- * __invoke__
- * __make_fused__
- * __deduce__
- [endsect]
- [section fused_procedure]
- [heading Description]
- An unary __poly_func_obj__ adapter template for __callable_obj__ target
- functions. It takes a __forward_sequence__ that contains the arguments for
- the target function.
- The result is discarded and the adapter's return type is `void`.
- The type of the target function is allowed to be const qualified or a
- reference. Const qualification is preserved and propagated appropriately
- (in other words, only const versions of [^operator()] can be used for a
- target function object that is const or, if the target function object
- is held by value, the adapter is const - these semantics have nothing to
- do with the const qualification of a member function, which is referring
- to the type of object pointed to by [^this] which is specified with the
- first element in the sequence passed to the adapter).
- If the target function is a pointer to a members function, the corresponding
- object can be specified as a reference, pointer, or smart pointer.
- In case of the latter, a freestanding [^get_pointer] function must be
- defined (Boost provides this function for [^std::auto_ptr] and
- __boost_shared_ptr_call__).
- The target function must not be a pointer to a member object (dereferencing
- such a pointer without returning anything does not make sense, so this case
- is not implemented).
- [heading Header]
- #include <boost/fusion/functional/adapter/fused_procedure.hpp>
- [heading Synopsis]
- template <typename Function>
- class fused_procedure;
- [heading Template parameters]
- [table
- [[Parameter] [Description] [Default]]
- [[`Function`] [__callable_obj__ type] []]
- ]
- [heading Model of]
- * __poly_func_obj__
- * __def_callable_obj__
- [variablelist Notation
- [[`R`] [A possibly const qualified __callable_obj__ type or reference type thereof]]
- [[`r`] [An object convertible to `R`]]
- [[`s`] [A __sequence__ of arguments that are accepted by `r`]]
- [[`f`] [An instance of `fused_procedure<R>`]]
- ]
- [heading Expression Semantics]
- [table
- [[Expression] [Semantics]]
- [[`fused_procedure<R>(r)`] [Creates a fused function as described above, initializes the target function with `r`.]]
- [[`fused_procedure<R>()`] [Creates a fused function as described above, attempts to use `R`'s default constructor.]]
- [[`f(s)`] [Calls `r` with the elements in `s` as its arguments.]]
- ]
- [heading Example]
- template<class SequenceOfSequences, class Func>
- void n_ary_for_each(SequenceOfSequences const & s, Func const & f)
- {
- __for_each__(__zip_view__<SequenceOfSequences>(s),
- fused_procedure<Func const &>(f));
- }
- void try_it()
- {
- __vector__<int,float> a(2,2.0f);
- __vector__<int,float> b(1,1.5f);
- using namespace boost::lambda;
- n_ary_for_each(__vector_tie__(a,b), _1 -= _2);
- assert(a == __make_vector__(1,0.5f));
- }
- [heading See also]
- * __fused__
- * __fused_function_object__
- * __invoke_procedure__
- * __make_fused_procedure__
- [endsect]
- [section fused_function_object]
- [heading Description]
- An unary __poly_func_obj__ adapter template for a __poly_func_obj__ target
- function. It takes a __forward_sequence__ that contains the arguments for the
- target function.
- The type of the target function is allowed to be const qualified or a
- reference. Const qualification is preserved and propagated appropriately
- (in other words, only const versions of [^operator()] can be used for an
- target function object that is const or, if the target function object
- is held by value, the adapter is const).
- [heading Header]
- #include <boost/fusion/functional/adapter/fused_function_object.hpp>
- [heading Synopsis]
- template <class Function>
- class fused_function_object;
- [heading Template parameters]
- [table
- [[Parameter] [Description] [Default]]
- [[`Function`] [__poly_func_obj__ type] []]
- ]
- [heading Model of]
- * __poly_func_obj__
- * __def_callable_obj__
- [variablelist Notation
- [[`R`] [A possibly const qualified __poly_func_obj__ type or reference type thereof]]
- [[`r`] [An object convertible to `R`]]
- [[`s`] [A __sequence__ of arguments that are accepted by `r`]]
- [[`f`] [An instance of `fused<R>`]]
- ]
- [heading Expression Semantics]
- [table
- [[Expression] [Semantics]]
- [[`fused_function_object<R>(r)`] [Creates a fused function as described above, initializes the target function with `r`.]]
- [[`fused_function_object<R>()`] [Creates a fused function as described above, attempts to use `R`'s default constructor.]]
- [[`f(s)`] [Calls `r` with the elements in `s` as its arguments.]]
- ]
- [heading Example]
- template<class SeqOfSeqs, class Func>
- typename __result_of_transform__< zip_view<SeqOfSeqs> const,
- fused_function_object<Func const &> >::type
- n_ary_transform(SeqOfSeqs const & s, Func const & f)
- {
- return __transform__(zip_view<SeqOfSeqs>(s),
- fused_function_object<Func const &>(f));
- }
- struct sub
- {
- template <typename Sig>
- struct result;
- template <class Self, typename T>
- struct result< Self(T,T) >
- { typedef typename remove_reference<T>::type type; };
- template<typename T>
- T operator()(T lhs, T rhs) const
- {
- return lhs - rhs;
- }
- };
- void try_it()
- {
- __vector__<int,float> a(2,2.0f);
- __vector__<int,float> b(1,1.5f);
- __vector__<int,float> c(1,0.5f);
- assert(c == n_ary_transform(__vector_tie__(a,b), sub()));
- }
- [heading See also]
- * __fused__
- * __fused_procedure__
- * __invoke_function_object__
- * __make_fused_function_object__
- * __deduce__
- [endsect]
- [section unfused]
- [heading Description]
- An n-ary __poly_func_obj__ adapter template for an unary __poly_func_obj__
- target function. When called, its arguments are bundled to a
- __random_access_sequence__ of references that is passed to the target function
- object.
- The nullary overload of the call operator can be removed by setting the
- second template parameter to `false`, which is very useful if the result type
- computation would result in a compile error, otherwise (nullary call
- operator's prototypes can't be templates and thus are instantiated as early
- as the class template).
- Only __lvalue__ arguments are accepted. To overcome this limitation, apply
- __boost_func_forward__.
- The type of the target function is allowed to be const qualified or a
- reference. Const qualification is preserved and propagated appropriately.
- In other words, only const versions of [^operator()] can be used if
- the target function object is const - or, in case the target function
- object is held by value, the adapter is const.
- [heading Header]
- #include <boost/fusion/functional/adapter/unfused.hpp>
- [heading Synopsis]
- template <class Function, bool AllowNullary = true>
- class unfused;
- [heading Template parameters]
- [table
- [[Parameter] [Description] [Default]]
- [[`Function`] [A unary __poly_func_obj__] []]
- [[`AllowNullary`] [Boolean constant] [true]]
- ]
- [heading Model of]
- * __poly_func_obj__
- * __def_callable_obj__
- [variablelist Notation
- [[`F`] [A possibly const qualified, unary __poly_func_obj__ type or reference type thereof]]
- [[`f`] [An object convertible to `F`]]
- [[`UL`] [The type `unfused<F>`]]
- [[`ul`] [An instance of `UL`, initialized with `f`]]
- [[`a0`...`aN`] [Arguments to `ul`]]
- ]
- [heading Expression Semantics]
- [table
- [[Expression] [Semantics]]
- [[`UL(f)`] [Creates a fused function as described above, initializes the target function with `f`.]]
- [[`UL()`] [Creates a fused function as described above, attempts to use `F`'s default constructor.]]
- [[`ul(a0`...`aN)`] [Calls `f` with a __sequence__ that contains references to the arguments `a0`...`aN`.]]
- ]
- [heading Example]
- struct fused_incrementer
- {
- template <class Seq>
- struct result
- {
- typedef void type;
- };
- template <class Seq>
- void operator()(Seq const & s) const
- {
- __for_each__(s,++boost::lambda::_1);
- }
- };
- void try_it()
- {
- unfused<fused_incrementer> increment;
- int a = 2; char b = 'X';
- increment(a,b);
- assert(a == 3 && b == 'Y');
- }
- [heading See also]
- * __unfused_typed__
- * __make_unfused__
- [endsect]
- [section unfused_typed]
- [heading Description]
- An n-ary __poly_func_obj__ adapter template for an unary __poly_func_obj__
- target function. When called, its arguments are bundled to a
- __random_access_sequence__ that is passed to the target function object.
- The call operators of resulting function objects are strictly typed
- (in other words, non-templatized) with the types from a __sequence__.
- The type of the target function is allowed to be const qualified or a
- reference. Const qualification is preserved and propagated appropriately
- (in other words, only const versions of [^operator()] can be used if
- the target function object is const - or, in case the target function object
- is held by value, the adapter is const).
- [note For Microsoft Visual C++ 7.1 (Visual Studio 2003) the detection
- of the Function Object's const qualification easily causes an internal error.
- Therefore the adapter is always treated as if it was const. ]
- [tip If the type sequence passed to this template contains
- non-reference elements, the element is copied only once - the call operator's
- signature is optimized automatically to avoid by-value parameters.]
- [heading Header]
- #include <boost/fusion/functional/adapter/unfused_typed.hpp>
- [heading Synopsis]
- template <class Function, class Sequence>
- class unfused_typed;
- [heading Template parameters]
- [table
- [[Parameter] [Description] [Default]]
- [[`Function`] [A unary __poly_func_obj__] []]
- [[`Sequence`] [A __sequence__] []]
- ]
- [heading Model of]
- * __poly_func_obj__
- * __def_callable_obj__
- [variablelist Notation
- [[`F`] [A possibly const qualified, unary __poly_func_obj__ type or reference type thereof]]
- [[`f`] [An object convertible to `F`]]
- [[`S`] [A __sequence__ of parameter types]]
- [[`UT`] [The type `unfused_typed<F,S>`]]
- [[`ut`] [An instance of `UT`, initialized with `f`]]
- [[`a0`...`aN`] [Arguments to `ut`, convertible to the types in `S`]]
- ]
- [heading Expression Semantics]
- [table
- [[Expression] [Semantics]]
- [[`UT(f)`] [Creates a fused function as described above, initializes the target function with `f`.]]
- [[`UT()`] [Creates a fused function as described above, attempts to use `F`'s default constructor.]]
- [[`ut(a0`...`aN)`] [Calls `f` with an instance of `S` (or a subsequence of `S` starting at the first element,
- if fewer arguments are given and the overload hasn't been disabled) initialized with
- `a0`...`aN`.]]
- ]
- [heading Example]
- struct add_assign // applies operator+=
- {
- typedef void result_type; // for simplicity
- template <typename T>
- void operator()(T & lhs, T const & rhs) const
- {
- lhs += rhs;
- }
- };
- template <class Tie>
- class fused_parallel_adder
- {
- Tie tie_dest;
- public:
- explicit fused_parallel_adder(Tie const & dest)
- : tie_dest(dest)
- { }
- typedef void result_type;
- template <class Seq>
- void operator()(Seq const & s) const
- {
- for_each( zip(tie_dest,s), fused<add_assign>() );
- }
- };
- // accepts a tie and creates a typed function object from it
- struct fused_parallel_adder_maker
- {
- template <typename Sig>
- struct result;
- template <class Self, class Seq>
- struct result< Self(Seq) >
- {
- typedef typename remove_reference<Seq>::type seq;
- typedef unfused_typed< fused_parallel_adder<seq>,
- typename mpl::transform<seq, remove_reference<_> >::type > type;
- };
- template <class Seq>
- typename result< void(Seq) >::type operator()(Seq const & tie)
- {
- return typename result< void(Seq) >::type(
- fused_parallel_adder<Seq>(tie) );
- }
- };
- unfused<fused_parallel_adder_maker> parallel_add;
- void try_it()
- {
- int a = 2; char b = 'X';
- // the second call is strictly typed with the types deduced from the
- // first call
- parallel_add(a,b)(3,2);
- parallel_add(a,b)(3);
- parallel_add(a,b)();
- assert(a == 8 && b == 'Z');
- }
- [heading See also]
- * __unfused__
- * __deduce__
- * __deduce_sequence__
- [endsect]
- [section Limits]
- [heading Header]
- #include <boost/fusion/functional/adapter/limits.hpp>
- [heading Macros]
- The following macros can be defined to change the maximum arity.
- The value used for these macros must not exceed `FUSION_MAX_VECTOR_SIZE`.
- The default is 6.
- * BOOST_FUSION_UNFUSED_MAX_ARITY
- * BOOST_FUSION_UNFUSED_TYPE_MAX_ARITY
- [endsect]
- [endsect] [/ Adapters]
- [/ ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ ]
- [section Generation]
- [section Functions]
- [section:mk_fused make_fused]
- [heading Description]
- Creates a __fused__ adapter for a given __def_callable_obj__. The usual
- __element_conversion__ is applied to the target function.
- [heading Synopsis]
- template <typename F>
- inline typename __result_of_make_fused__<F>::type
- make_fused(F const & f);
- [heading Parameters]
- [table
- [[Parameter] [Requirement] [Description]]
- [[`f`] [Model of __def_callable_obj__] [The function to transform.]]
- ]
- [heading Expression Semantics]
- make_fused(f);
- [*Return type]: A specialization of __fused__.
- [*Semantics]: Returns a __fused__ adapter for `f`.
- [heading Header]
- #include <boost/fusion/functional/generation/make_fused.hpp>
- #include <boost/fusion/include/make_fused.hpp>
- [heading Example]
- float sub(float a, float b) { return a - b; }
- void try_it()
- {
- __vector__<int,float> a(2,2.0f);
- __vector__<int,float> b(1,1.5f);
- __vector__<float,float> c(1.0f,0.5f);
- assert(c == __transform__(__zip__(a,b), make_fused(& sub)));
- assert(c == __transform__(__zip__(a,b), make_fused(__std_minus_doc__<float>())));
- }
- [heading See also]
- * __fused__
- * __deduce__
- * __result_of_make_fused__
- [endsect]
- [section:mk_fused_proc make_fused_procedure]
- [heading Description]
- Creates a __fused_procedure__ adapter for a given __def_callable_obj__.
- The usual __element_conversion__ applied to the target function.
- [heading Synopsis]
- template <typename F>
- inline typename __result_of_make_fused_procedure__<F>::type
- make_fused_procedure(F const & f);
- [heading Parameters]
- [table
- [[Parameter] [Requirement] [Description]]
- [[`f`] [Model of __callable_obj__] [The function to transform.]]
- ]
- [heading Expression Semantics]
- make_fused_procedure(f);
- [*Return type]: A specialization of __fused_procedure__.
- [*Semantics]: Returns a __fused_procedure__ adapter for `f`.
- [heading Header]
- #include <boost/fusion/functional/generation/make_fused_procedure.hpp>
- #include <boost/fusion/include/make_fused_procedure.hpp>
- [heading Example]
- __vector__<int,int,int> v(1,2,3);
- using namespace boost::lambda;
- make_fused_procedure(_1 += _2 - _3)(v);
- assert(__front__(v) == 0);
- [heading See also]
- * __fused_procedure__
- * __deduce__
- * __result_of_make_fused_procedure__
- [endsect]
- [section:mk_fused_fobj make_fused_function_object]
- [heading Description]
- Creates a __fused_function_object__ adapter for a given __def_callable_obj__.
- The usual __element_conversion__ is applied to the target function.
- [heading Synopsis]
- template <typename F>
- inline typename __result_of_make_fused_function_object__<F>::type
- make_fused_function_object(F const & f);
- [heading Parameters]
- [table
- [[Parameter] [Requirement] [Description]]
- [[`f`] [Model of __poly_func_obj__] [The function to transform.]]
- ]
- [heading Expression Semantics]
- make_fused_function_object(f);
- [*Return type]: A specialization of __fused_function_object__.
- [*Semantics]: Returns a __fused_function_object__ adapter for `f`.
- [heading Header]
- #include <boost/fusion/functional/generation/make_fused_function_object.hpp>
- #include <boost/fusion/include/make_fused_function_object.hpp>
- [heading Example]
- struct sub
- {
- template <typename Sig>
- struct result;
- template <class Self, typename T>
- struct result< Self(T,T) >
- { typedef typename remove_reference<T>::type type; };
- template<typename T>
- T operator()(T lhs, T rhs) const
- {
- return lhs - rhs;
- }
- };
- void try_it()
- {
- __vector__<int,float> a(2,2.0f);
- __vector__<int,float> b(1,1.5f);
- __vector__<int,float> c(1,0.5f);
- assert(c == __transform__(__zip__(a,b), make_fused_function_object(sub())));
- }
- [heading See also]
- * __fused_function_object__
- * __deduce__
- * __result_of_make_fused_function_object__
- [endsect]
- [section:mk_unfused make_unfused]
- [heading Description]
- Creates a __unfused__ adapter for a given, unary __poly_func_obj__.
- The usual __element_conversion__ is applied to the target function.
- [heading Synopsis]
- template <typename F>
- inline typename __result_of_make_unfused__<F>::type
- make_unfused(F const & f);
- [heading Parameters]
- [table
- [[Parameter] [Requirement] [Description]]
- [[`f`] [Model of __poly_func_obj__] [The function to transform.]]
- ]
- [heading Expression Semantics]
- make_unfused(f);
- [*Return type]: A specialization of __unfused__.
- [*Semantics]: Returns a __unfused__ adapter for `f`.
- [heading Header]
- #include <boost/fusion/functional/generation/make_unfused.hpp>
- #include <boost/fusion/include/make_unfused.hpp>
- [heading Example]
- struct fused_incrementer
- {
- template <class Seq>
- struct result
- {
- typedef void type;
- };
- template <class Seq>
- void operator()(Seq const & s) const
- {
- __for_each__(s,++boost::lambda::_1);
- }
- };
- void try_it()
- {
- int a = 2; char b = 'X';
- make_unfused(fused_incrementer())(a,b);
- assert(a == 3 && b == 'Y');
- }
- [heading See also]
- * __unfused__
- * __deduce__
- * __result_of_make_unfused__
- [endsect]
- [endsect] [/ Functions]
- [section Metafunctions]
- [section:mk_fused make_fused]
- [heading Description]
- Returns the result type of __make_fused__.
- [heading Header]
- #include <boost/fusion/functional/generation/make_fused.hpp>
- #include <boost/fusion/include/make_fused.hpp>
- [heading Synopsis]
- namespace result_of
- {
- template<typename Function>
- struct make_fused
- {
- typedef __unspecified__ type;
- };
- }
- [heading See also]
- * __make_fused__
- [endsect]
- [section:mk_fused_proc make_fused_procedure]
- [heading Description]
- Returns the result type of __make_fused_procedure__.
- [heading Header]
- #include <boost/fusion/functional/generation/make_fused_procedure.hpp>
- #include <boost/fusion/include/make_fused_procedure.hpp>
- [heading Synopsis]
- namespace result_of
- {
- template<typename Function>
- struct make_fused_procedure
- {
- typedef __unspecified__ type;
- };
- }
- [heading See also]
- * __make_fused_procedure__
- [endsect]
- [section:mk_fused_fobj make_fused_function_object]
- [heading Description]
- Returns the result type of __make_fused_function_object__.
- [heading Header]
- #include <boost/fusion/functional/generation/make_fused_function_object.hpp>
- #include <boost/fusion/include/make_fused_function_object.hpp>
- [heading Synopsis]
- namespace result_of
- {
- template<typename Function>
- struct make_fused_function_object
- {
- typedef __unspecified__ type;
- };
- }
- [heading See also]
- * __make_fused_function_object__
- [endsect]
- [section:mk_unfused make_unfused]
- [heading Description]
- Returns the result type of __make_unfused__.
- [heading Header]
- #include <boost/fusion/functional/generation/make_unfused.hpp>
- #include <boost/fusion/include/make_unfused.hpp>
- [heading Synopsis]
- namespace result_of
- {
- template<typename Function>
- struct make_unfused
- {
- typedef __unspecified__ type;
- };
- }
- [heading See also]
- * __make_unfused__
- [endsect]
- [endsect] [/ Metafunctions]
- [endsect] [/ Generation]
- [endsect] [/ Functional ]
|