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dft_tools/triqs/clef/clef.hpp
Olivier Parcollet 1dd2d9e691 correction after compiling on linux gcc 4.8.1/ clang 3.3 
- clef : lazy_method is broken . remove it from the test for the moment.
2013-09-08 15:35:57 +02:00

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/*******************************************************************************
*
* TRIQS: a Toolbox for Research in Interacting Quantum Systems
*
* Copyright (C) 2012-2013 by O. Parcollet
*
* TRIQS 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 3 of the License, or (at your option) any later
* version.
*
* TRIQS is distributed in the hope that it will be useful, but WITHOUT ANY
* WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
* FOR A PARTICULAR PURPOSE. See the GNU General Public License for more
* details.
*
* You should have received a copy of the GNU General Public License along with
* TRIQS. If not, see <http://www.gnu.org/licenses/>.
*
******************************************************************************/
#ifndef TRIQS_CLEF_CORE_H
#define TRIQS_CLEF_CORE_H
#include <triqs/utility/first_include.hpp>
#include <triqs/utility/macros.hpp>
#include <triqs/utility/compiler_details.hpp>
#include <tuple>
#include <type_traits>
#include <functional>
#include <memory>
#include <complex>
#include <boost/preprocessor/stringize.hpp>
#include <boost/preprocessor/repetition/repeat_from_to.hpp>
#include <boost/preprocessor/repetition/enum.hpp>
#include <boost/preprocessor/arithmetic/inc.hpp>
#define TRIQS_CLEF_MAXNARGS 8
namespace triqs { namespace clef {
typedef unsigned long long ull_t;
namespace tags { struct function_class{}; struct function{}; struct subscript{}; struct terminal{}; struct if_else{}; struct unary_op{}; struct binary_op{}; }
// Compute the type to put in the expression tree.
// If T is a lvalue reference, pack it into a reference_wrapper, unless force_copy_in_expr<T>::value == true
// If T is an rvalue reference, we store it as the type (using move semantics).
template<typename T> struct force_copy_in_expr : std::false_type{};
template<typename T> struct force_copy_in_expr<T const> : force_copy_in_expr<T>{};
template< class T > struct expr_storage_t {typedef T type;};
template< class T > struct expr_storage_t<T&> : std::conditional<force_copy_in_expr<T>::value, T ,std::reference_wrapper<T>>{};
template< class T > struct expr_storage_t<T&&> {typedef T type;};
/* ---------------------------------------------------------------------------------------------------
* Placeholder and corresponding traits
* --------------------------------------------------------------------------------------------------- */
template<int i, typename T> class pair; // forward
// a placeholder is an empty struct, labelled by an int.
template<int N> struct placeholder {
static_assert( (N>=0) && (N<64) , "Placeholder number limited to [0,63]");
static constexpr int index = N;
template <typename RHS> pair<N,RHS> operator = (RHS && rhs) { return {std::forward<RHS>(rhs)};}
};
// placeholder will always be copied (they are empty anyway).
template< int N > struct force_copy_in_expr<placeholder<N>> : std::true_type{};
// represent a couple (placeholder, value).
template<int N, typename U> struct pair {
U rhs;
static constexpr int p = N;
typedef typename remove_cv_ref <U>::type value_type;
};
// ph_set is a trait that given a pack of type, returns the set of placeholders they contain
// it returns a int in binary coding : bit N in the int is 1 iif at least one T is lazy and contains placeholder<N>
template<typename... T> struct ph_set;
template<typename T0, typename... T> struct ph_set<T0,T...>{static constexpr ull_t value= ph_set<T0>::value| ph_set<T...>::value;};
template<typename T> struct ph_set<T> {static constexpr ull_t value= 0;};
template<int N> struct ph_set<placeholder<N>> {static constexpr ull_t value= 1ull<<N;};
template<int i, typename T> struct ph_set<pair<i,T> > : ph_set<placeholder<i>>{};
// in_any_lazy : trait to detect if any of Args is a lazy expression
template<typename... Args> struct is_any_lazy : std::false_type {};
template<int N> struct is_any_lazy <placeholder <N> > : std::true_type {};
template <typename T> struct is_any_lazy< T > : std::false_type {};
template <typename T> struct is_any_lazy< T&& > : is_any_lazy<T> {};
template <typename T> struct is_any_lazy< T& > : is_any_lazy<T> {};
template <typename T> struct is_any_lazy< T const > : is_any_lazy<T> {};
template<typename T, typename... Args> struct is_any_lazy<T, Args...> :
std::integral_constant<bool, is_any_lazy<T>::value || is_any_lazy<Args...>::value> {};
template<typename T>
constexpr bool ClefExpression() { return is_any_lazy<T>::value;}
template<typename T> struct is_clef_expression : is_any_lazy<T>{};
/* ---------------------------------------------------------------------------------------------------
* Node of the expression tree
* --------------------------------------------------------------------------------------------------- */
template<typename Tag, typename... T> struct expr {
// T can be U, U & (a reference or a value).
typedef std::tuple<T...> childs_t;
childs_t childs;
expr(expr const & x) = default;
expr(expr && x) noexcept : childs(std::move(x.childs)) {}
// a constructor with the Tag make it unambiguous with other constructors...
template<typename... Args> expr(Tag, Args&&...args) : childs(std::forward<Args>(args)...) {}
// [] returns a new lazy expression, with one more layer
template<typename Args>
expr<tags::subscript, expr, typename expr_storage_t<Args>::type > operator[](Args && args) const
{ return {tags::subscript(), *this,std::forward<Args>(args)};}
// () also ...
template< typename... Args >
expr<tags::function, expr, typename expr_storage_t<Args>::type...> operator()(Args && ... args) const
{ return {tags::function(), *this,std::forward<Args>(args)...};}
// assignement is in general deleted
expr & operator= (expr const &) = delete; // no ordinary assignment
expr & operator= (expr &&) = default; // move assign ok
// however, this is ok in the case f(i,j) = expr, where f is a clef::function
template<typename RHS, typename CH = childs_t>
ENABLE_IF(std::is_base_of<tags::function_class, typename std::tuple_element<0,CH>::type>)
operator= (RHS const & rhs) { *this << rhs;}
template<typename RHS, typename CH = childs_t>
DISABLE_IF(std::is_base_of<tags::function_class, typename std::tuple_element<0,CH>::type>)
operator= (RHS const & rhs) = delete;
};
// set some traits
template<typename Tag, typename... T> struct ph_set< expr<Tag,T... > > : ph_set<T...> {};
template<typename Tag, typename... T> struct is_any_lazy< expr<Tag,T... > >: std::true_type {};
// if we want that subexpression are copied ?
template<typename Tag, typename... T> struct force_copy_in_expr< expr<Tag,T... > > : std::true_type{};
/* ---------------------------------------------------------------------------------------------------
* The basic operations put in a template....
* --------------------------------------------------------------------------------------------------- */
template<typename Tag> struct operation;
// a little function to clean the reference_wrapper
template<typename U> U & _cl(U & x) { return x;}
template<typename U> U & _cl(std::reference_wrapper<U> x) { return x.get();}
/// Terminal
template<> struct operation<tags::terminal> { template<typename L> L operator()(L&& l) const { return std::forward<L>(l);} };
/// Function call
template<> struct operation<tags::function> {
template<typename F, typename... Args> auto operator()(F const & f, Args const & ... args) const DECL_AND_RETURN(_cl(f)(_cl(args)...));
};
/// [ ] Call
template<> struct operation<tags::subscript> {
template<typename F, typename Args> auto operator()(F const & f, Args const & args) const DECL_AND_RETURN(_cl(f)[_cl(args)]);
};
// all binary operators....
#define TRIQS_CLEF_OPERATION(TAG,OP)\
namespace tags { struct TAG : binary_op { static const char * name() { return BOOST_PP_STRINGIZE(OP);} };}\
template<> struct operation<tags::TAG> {\
template<typename L, typename R> auto operator()(L const & l, R const & r) const DECL_AND_RETURN ( _cl(l) OP _cl(r));\
};\
template<typename L, typename R>\
typename std::enable_if<is_any_lazy<L,R>::value, expr<tags::TAG,typename expr_storage_t<L>::type,typename expr_storage_t<R>::type> >::type \
operator OP (L && l, R && r) { return {tags::TAG(),std::forward<L>(l),std::forward<R>(r)};}\
TRIQS_CLEF_OPERATION(plus, +);
TRIQS_CLEF_OPERATION(minus, -);
TRIQS_CLEF_OPERATION(multiplies, *);
TRIQS_CLEF_OPERATION(divides, /);
TRIQS_CLEF_OPERATION(greater, >);
TRIQS_CLEF_OPERATION(less, <);
TRIQS_CLEF_OPERATION(leq, <=);
TRIQS_CLEF_OPERATION(geq, >=);
TRIQS_CLEF_OPERATION(eq, ==);
#undef TRIQS_CLEF_OPERATION
// all unary operators....
#define TRIQS_CLEF_OPERATION(TAG,OP)\
namespace tags { struct TAG : unary_op { static const char * name() { return BOOST_PP_STRINGIZE(OP);} };}\
template<> struct operation<tags::TAG> {\
template<typename L> auto operator()(L const & l) const DECL_AND_RETURN (OP _cl(l));\
};\
template<typename L>\
typename std::enable_if<is_any_lazy<L>::value, expr<tags::TAG,typename expr_storage_t<L>::type> >::type \
operator OP (L && l) { return {tags::TAG(),std::forward<L>(l)};}\
TRIQS_CLEF_OPERATION(negate, -);
TRIQS_CLEF_OPERATION(loginot, !);
#undef TRIQS_CLEF_OPERATION
/// the only ternary node : expression if
template<> struct operation<tags::if_else> {
template<typename C, typename A, typename B> auto operator()(C const & c, A const & a, B const & b) const DECL_AND_RETURN (_cl(c) ? _cl(a): _cl(b));
};
// operator is : if_else( Condition, A, B)
template<typename C, typename A, typename B>
expr<tags::if_else,typename expr_storage_t<C>::type,typename expr_storage_t<A>::type,typename expr_storage_t<B>::type>
if_else(C && c, A && a, B && b) { return {tags::if_else(),std::forward<C>(c),std::forward<A>(a),std::forward<B>(b)};}
/* ---------------------------------------------------------------------------------------------------
* Evaluation of the expression tree.
* --------------------------------------------------------------------------------------------------- */
template<typename Tag, bool IsLazy, typename... Args> struct operation2;
template<typename Tag, typename... Args> struct operation2<Tag, true, Args...> {
typedef expr<Tag,typename remove_cv_ref<Args>::type ...> rtype;
rtype operator()(Args const & ... args) const {return rtype {Tag(), args...};}
};
template<typename Tag, typename... Args> struct operation2<Tag, false, Args...> {
typedef typename std::remove_reference<typename std::result_of<operation<Tag>(Args...)>::type>::type rtype;
// remove the reference because of ternary if_else in which decltype returns a ref...
rtype operator()(Args const & ... args) const {return operation<Tag>()(args...); }
};
// Generic case : do nothing (for the leaf of the tree except placeholder)
template<typename T, typename ... Pairs> struct evaluator{
typedef T rtype;
rtype operator()(T const & k, Pairs const &... pairs) {return k;}
};
// placeholder
template<int N, int i, typename T, typename... Pairs> struct evaluator< placeholder<N>, pair<i,T>, Pairs... > {
typedef evaluator< placeholder<N>, Pairs...> eval_t;
typedef typename eval_t::rtype rtype;
rtype operator()(placeholder<N>, pair<i,T> const &, Pairs const& ... pairs) { return eval_t()(placeholder<N>(), pairs...);}
};
template<int N, typename T, typename... Pairs> struct evaluator< placeholder<N>, pair<N,T>, Pairs... > {
typedef T const & rtype;
//typedef typename pair<N,T>::value_type const & rtype;
rtype operator()(placeholder<N>, pair<N,T> const & p, Pairs const& ...) { return p.rhs;}
};
// general expr node
template<typename Tag, typename... Childs, typename... Pairs> struct evaluator<expr<Tag, Childs...>, Pairs...> {
typedef operation2<Tag, is_any_lazy<typename evaluator<Childs, Pairs...>::rtype... >::value, typename evaluator<Childs, Pairs...>::rtype... > OPTYPE;
typedef typename OPTYPE::rtype rtype;
// first done manually for clearer error messages ...
template< int arity = sizeof...(Childs)>
typename std::enable_if< arity==1, rtype>::type
operator()(expr<Tag, Childs...> const & ex, Pairs const & ... pairs) const
{ return OPTYPE()(eval(std::get<0>(ex.childs),pairs...) );}
template< int arity = sizeof...(Childs)>
typename std::enable_if< arity==2, rtype>::type
operator()(expr<Tag, Childs...> const & ex, Pairs const & ... pairs) const
{ return OPTYPE()(eval(std::get<0>(ex.childs),pairs...),eval(std::get<1>(ex.childs),pairs...) );}
#define AUX(z,p,unused) eval(std::get<p>(ex.childs),pairs...)
#define IMPL(z, NN, unused) \
template< int arity = sizeof...(Childs)>\
typename std::enable_if< arity==NN, rtype>::type\
operator()(expr<Tag, Childs...> const & ex, Pairs const & ... pairs) const\
{ return OPTYPE()(BOOST_PP_ENUM(NN,AUX,nil));}
BOOST_PP_REPEAT_FROM_TO(3,BOOST_PP_INC(TRIQS_CLEF_MAXNARGS), IMPL, nil);
#undef AUX
#undef IMPL
};
#ifdef TRIQS_CLEF_EVAL_SHORT_CIRCUIT
// A short circuit if intersection of ph and is 0, no need to evaluate the whole tree......
// Seems useless, && the second eval is not correct if hte expression is a terminal.
template<typename T, typename... Pairs>
typename std::enable_if< (ph_set<T>::value & ph_set<Pairs...>::value) !=0, typename evaluator<T,Pairs...>::rtype > ::type
eval (T const & ex, Pairs const &... pairs) { return evaluator<T, Pairs...>()(ex, pairs...); }
template<typename T, typename... Pairs>
typename std::enable_if< (ph_set<T>::value & ph_set<Pairs...>::value) ==0, T const &> ::type
eval (T const & ex, Pairs const &... pairs) { return ex;}
#else
// The general eval function for expressions
template<typename T, typename... Pairs>
typename evaluator<T,Pairs...>::rtype
eval (T const & ex, Pairs const &... pairs) { return evaluator<T, Pairs...>()(ex, pairs...); }
#endif
/* ---------------------------------------------------------------------------------------------------
* make_function : transform an expression to a function
* --------------------------------------------------------------------------------------------------- */
template< typename Expr, int... Is> struct make_fun_impl {
Expr ex; // keep a copy of the expression
make_fun_impl(Expr const & ex_) : ex(ex_) {}
// gcc 4.6 crashes (!!!) on the first variant
#ifndef TRIQS_COMPILER_OBSOLETE_GCC
template<typename... Args>
typename evaluator<Expr,pair<Is,Args>...>::rtype
operator()(Args &&... args) const
{ return evaluator<Expr,pair<Is,Args>...>() ( ex, pair<Is,Args>{std::forward<Args>(args)}...); }
#else
template<typename... Args> struct __eval {
typedef evaluator<Expr,pair<Is,Args>...> eval_t;
typedef typename eval_t::rtype rtype;
rtype operator()(Expr const &ex , Args &&... args) const { return eval_t() ( ex, pair<Is,Args>{std::forward<Args>(args)}...); }
};
template<typename... Args>
typename __eval<Args...>::rtype operator()(Args &&... args) const { return __eval<Args...>() ( ex, std::forward<Args>(args)...); }
#endif
};
// values of the ph, excluding the Is ...
template<ull_t x, int... Is> struct ph_filter;
template<ull_t x, int I0, int... Is> struct ph_filter<x,I0,Is...> { static constexpr ull_t value = ph_filter<x,Is...>::value & (~ (1ull<<I0));};
template<ull_t x> struct ph_filter<x> { static constexpr ull_t value = x; };
template< typename Expr, int... Is> struct ph_set<make_fun_impl<Expr,Is...> > { static constexpr ull_t value = ph_filter <ph_set<Expr>::value, Is...>::value;};
template< typename Expr, int... Is> struct is_any_lazy<make_fun_impl<Expr,Is...> > : std::integral_constant<bool,ph_set<make_fun_impl<Expr,Is...>>::value !=0>{};
template< typename Expr, int... Is> struct force_copy_in_expr<make_fun_impl<Expr,Is...> > : std::true_type{};
template< typename Expr, int... Is,typename... Pairs> struct evaluator<make_fun_impl<Expr,Is...>, Pairs...> {
typedef evaluator<Expr,Pairs...> e_t;
typedef make_fun_impl<typename e_t::rtype, Is...> rtype;
rtype operator()(make_fun_impl<Expr,Is...> const & f, Pairs const & ... pairs) const { return rtype( e_t()(f.ex, pairs...));}
};
template< typename Expr, typename ... Phs>
make_fun_impl<typename remove_cv_ref <Expr>::type,Phs::index...>
make_function(Expr && ex, Phs...) { return {ex}; }
namespace result_of {
template< typename Expr, typename ... Phs> struct make_function {
typedef make_fun_impl<typename remove_cv_ref<Expr>::type,Phs::index...> type;
};
}
template<int ... N> struct ph_list {};
template<int ... N> ph_list<N...> var( placeholder<N> ...) { return {};}
template<typename Expr, int ... N>
auto operator >> (ph_list<N...>, Expr const & ex) DECL_AND_RETURN( make_function(ex, placeholder<N>()...));
/* --------------------------------------------------------------------------------------------------
* make_function
* x_ >> expression is the same as make_function(expression,x)
* --------------------------------------------------------------------------------------------------- */
template <int N, typename Expr>
make_fun_impl<Expr,N > operator >> (placeholder<N> p, Expr&& ex) { return {ex}; }
/* ---------------------------------------------------------------------------------------------------
* Auto assign for ()
* --------------------------------------------------------------------------------------------------- */
// by default it is deleted = not implemented : every class has to define it...
template<typename T, typename F> void triqs_clef_auto_assign (T,F) = delete;
// remove the ref_wrapper, terminal ...
template<typename T, typename F> void triqs_clef_auto_assign (std::reference_wrapper<T> R ,F && f) { triqs_clef_auto_assign(R.get(),std::forward<F>(f));}
template<typename T, typename F> void triqs_clef_auto_assign (expr<tags::terminal,T> const & t,F && f) { triqs_clef_auto_assign(std::get<0>(t.childs),std::forward<F>(f));}
// auto assign of an expr ? (for chain calls) : just reuse the same operator
template<typename Tag, typename... Childs, typename RHS>
void triqs_clef_auto_assign (expr<Tag,Childs...> && ex, RHS const & rhs) { ex << rhs;}
template<typename Tag, typename... Childs, typename RHS>
void triqs_clef_auto_assign (expr<Tag,Childs...> const & ex, RHS const & rhs) { ex << rhs;}
// The case A(x_,y_) = RHS : we form the function (make_function) and call auto_assign (by ADL)
template<typename F, typename RHS, int... Is>
void operator<<(expr<tags::function, F, placeholder<Is>...> && ex, RHS && rhs) {
triqs_clef_auto_assign(std::get<0>(ex.childs), make_function(std::forward<RHS>(rhs), placeholder<Is>()...));
}
template<typename F, typename RHS, int... Is>
void operator<<(expr<tags::function, F, placeholder<Is>...> const & ex, RHS && rhs) {
triqs_clef_auto_assign(std::get<0>(ex.childs), make_function(std::forward<RHS>(rhs), placeholder<Is>()...));
}
template<typename F, typename RHS, int... Is>
void operator<<(expr<tags::function, F, placeholder<Is>...> & ex, RHS && rhs) {
triqs_clef_auto_assign(std::get<0>(ex.childs), make_function(std::forward<RHS>(rhs), placeholder<Is>()...));
}
// any other case e.g. f(x_+y_) = RHS etc .... which makes no sense : compiler will stop
template<typename F, typename RHS, typename... T>
void operator<<(expr<tags::function, F, T...> && ex, RHS && rhs) = delete;
template<typename F, typename RHS, typename... T>
void operator<<(expr<tags::function, F, T...> const & ex, RHS && rhs) = delete;
/* ---------------------------------------------------------------------------------------------------
* Auto assign for []
* --------------------------------------------------------------------------------------------------- */
// by default it is deleted = not implemented : every class has to define it...
template<typename T, typename F> void triqs_clef_auto_assign_subscript (T,F) = delete;
// remove the ref_wrapper, terminal ...
template<typename T, typename F> void triqs_clef_auto_assign_subscript (std::reference_wrapper<T> R ,F && f)
{ triqs_clef_auto_assign_subscript(R.get(),std::forward<F>(f));}
template<typename T, typename F> void triqs_clef_auto_assign_subscript (expr<tags::terminal,T> const & t,F && f)
{ triqs_clef_auto_assign_subscript(std::get<0>(t.childs),std::forward<F>(f));}
// auto assign of an expr ? (for chain calls) : just reuse the same operator
template<typename Tag, typename... Childs, typename RHS>
void triqs_clef_auto_assign_subscript (expr<Tag,Childs...> && ex, RHS const & rhs) { ex << rhs;}
template<typename Tag, typename... Childs, typename RHS>
void triqs_clef_auto_assign_subscript (expr<Tag,Childs...> const & ex, RHS const & rhs) { ex << rhs;}
// Same thing for the [ ]
template<typename F, typename RHS, int... Is>
void operator<<(expr<tags::subscript, F, placeholder<Is>...> const & ex, RHS && rhs) {
triqs_clef_auto_assign_subscript(std::get<0>(ex.childs), make_function(std::forward<RHS>(rhs), placeholder<Is>()...));
}
template<typename F, typename RHS, int... Is>
void operator<<(expr<tags::subscript, F, placeholder<Is>...> && ex, RHS && rhs) {
triqs_clef_auto_assign_subscript(std::get<0>(ex.childs), make_function(std::forward<RHS>(rhs), placeholder<Is>()...));
}
template<typename F, typename RHS, typename... T>
void operator<<(expr<tags::subscript, F, T...> && ex, RHS && rhs) = delete;
template<typename F, typename RHS, typename... T>
void operator<<(expr<tags::subscript, F, T...> const & ex, RHS && rhs) = delete;
/* --------------------------------------------------------------------------------------------------
* Create a terminal node of an object. the from clone version force copying the object
* --------------------------------------------------------------------------------------------------- */
// make a node with the ref, unless it is an rvalue (which is moved).
template<typename T> expr<tags::terminal,typename expr_storage_t<T>::type >
make_expr(T && x){ return {tags::terminal(), std::forward<T>(x)};}
// make a node from a copy of the object
template<typename T> expr<tags::terminal,typename remove_cv_ref<T>::type >
make_expr_from_clone(T && x){ return {tags::terminal(), std::forward<T>(x)};}
/* --------------------------------------------------------------------------------------------------
* Create a call node of an object
* The object can be kept as a : a ref, a copy, a view
* --------------------------------------------------------------------------------------------------- */
template<typename T> struct arity { static constexpr int value =-1;};
namespace _result_of {
template< typename Obj, typename... Args > struct make_expr_call :
std::enable_if< is_any_lazy<Args...>::value, expr<tags::function,typename expr_storage_t<Obj>::type, typename expr_storage_t<Args>::type ...> > {
static_assert (((arity<Obj>::value==-1) || (arity<Obj>::value == sizeof...(Args))), "Object called with a wrong number of arguments");
};
}
template< typename Obj, typename... Args >
typename _result_of::make_expr_call<Obj,Args...>::type
make_expr_call(Obj&& obj, Args &&... args) { return {tags::function(),std::forward<Obj>(obj), std::forward<Args>(args)...};}
/* --------------------------------------------------------------------------------------------------
* Create a [] call (subscript) node of an object
* The object can be kept as a : a ref, a copy, a view
* --------------------------------------------------------------------------------------------------- */
namespace _result_of {
template< typename Obj, typename Arg> struct make_expr_subscript :
std::enable_if< is_any_lazy<Arg>::value, expr<tags::subscript,typename expr_storage_t<Obj>::type, typename expr_storage_t<Arg>::type> > {};
}
template< typename Obj, typename Arg>
typename _result_of::make_expr_subscript<Obj,Arg>::type
make_expr_subscript(Obj&& obj, Arg && arg) { return {tags::subscript(),std::forward<Obj>(obj), std::forward<Arg>(arg)};}
/* --------------------------------------------------------------------------------------------------
* function class : stores any expression polymorphically
* f(x_,y_ ) = an expression associates this expression dynamically to f, which
* can then be used as a std::function of the same signature...
* --------------------------------------------------------------------------------------------------- */
template<typename F> class function;
template<typename ReturnType, typename... T> class function<ReturnType(T...)> : tags::function_class {
typedef std::function<ReturnType(T...)> std_function_type;
mutable std::shared_ptr <void> _exp; // CLEAN THIS MUTABLE ?
mutable std::shared_ptr < std_function_type > _fnt_ptr;
public:
function():_fnt_ptr{std::make_shared<std_function_type> ()}{}
template<typename Expr, typename... X>
explicit function(Expr const & _e, X... x) : _exp(new Expr(_e)),_fnt_ptr(new std_function_type(make_function(_e, x...))){}
ReturnType operator()(T const &... t) const { return (*_fnt_ptr)(t...);}
#ifndef TRIQS_COMPILER_OBSOLETE_GCC
template< typename... Args>
auto operator()( Args&&... args ) const DECL_AND_RETURN(make_expr_call (*this,std::forward<Args>(args)...));
#else
template< typename... Args>
typename _result_of::make_expr_call<function const & ,Args...>::type
operator()( Args&&... args ) const { return make_expr_call (*this,args...);}
#endif
template<typename RHS> friend void triqs_clef_auto_assign (function const & x, RHS rhs) {
* (x._fnt_ptr) = std_function_type (rhs);
x._exp = std::shared_ptr <void> (new typename std::remove_cv<decltype(rhs.ex)>::type (rhs.ex));
}
};
template<typename F> struct force_copy_in_expr <function<F>> : std::true_type{};
/* --------------------------------------------------------------------------------------------------
* The macro to make any function lazy
* TRIQS_CLEF_MAKE_FNT_LAZY (Arity,FunctionName ) : creates a new function in the triqs::lazy namespace
* taking expressions (at least one argument has to be an expression)
* The lookup happens by ADL, so IT MUST BE USED IN THE triqs::lazy namespace
* --------------------------------------------------------------------------------------------------- */
#define TRIQS_CLEF_MAKE_FNT_LAZY(name)\
struct name##_lazy_impl { \
template<typename... A> auto operator()(A&&... a) const DECL_AND_RETURN (name(std::forward<A>(a)...));\
};\
template< typename... A> \
auto name( A&& ... a) DECL_AND_RETURN(make_expr_call(name##_lazy_impl(),std::forward<A>(a)...));
#ifndef TRIQS_COMPILER_OBSOLETE_GCC
#define TRIQS_CLEF_IMPLEMENT_LAZY_METHOD(TY,name)\
struct __clef_lazy_method_impl_##name { \
TY * _x;\
template<typename... A> auto operator()(A&&... a) const DECL_AND_RETURN (_x->name(std::forward<A>(a)...));\
friend std::ostream & operator<<(std::ostream & out, __clef_lazy_method_impl_##name const & x) { return out<<BOOST_PP_STRINGIZE(TY)<<"."<<BOOST_PP_STRINGIZE(name);}\
};\
template< typename... A> \
auto name( A&& ... a) DECL_AND_RETURN (make_expr_call(__clef_lazy_method_impl_##name{this},std::forward<A>(a)...));
#define TRIQS_CLEF_IMPLEMENT_LAZY_CALL(...)\
template< typename... Args>\
auto operator()(Args&&... args ) const & DECL_AND_RETURN(make_expr_call (*this,std::forward<Args>(args)...));\
\
template< typename... Args>\
auto operator()(Args&&... args ) & DECL_AND_RETURN(make_expr_call (*this,std::forward<Args>(args)...));\
\
template< typename... Args>\
auto operator()(Args&&... args ) && DECL_AND_RETURN(make_expr_call (std::move(*this),std::forward<Args>(args)...));\
#else
#define TRIQS_CLEF_IMPLEMENT_LAZY_METHOD(TY,name,RETURN_TYPE)\
struct __clef_lazy_method_impl_##name { \
TY * _x;\
template<typename... A> RETURN_TYPE operator()(A&&... a) const {return ((*_x).name(std::forward<A>(a)...));}\
friend std::ostream & operator<<(std::ostream & out, __clef_lazy_method_impl_##name const & x) { return out<<BOOST_PP_STRINGIZE(TY)<<"."<<BOOST_PP_STRINGIZE(name);}\
};\
template< typename... A> \
typename _result_of::make_expr_call<__clef_lazy_method_impl_##name, A...>::type\
name( A&& ... a) {return make_expr_call(__clef_lazy_method_impl_##name{this},std::forward<A>(a)...);}
#define TRIQS_CLEF_IMPLEMENT_LAZY_CALL(TY)\
template< typename... Args>\
typename triqs::clef::_result_of::make_expr_call<TY const &,Args...>::type\
operator()(Args&&... args ) const {return make_expr_call (*this,std::forward<Args>(args)...);}\
\
template< typename... Args>\
typename triqs::clef::_result_of::make_expr_call<TY &,Args...>::type\
operator()(Args&&... args ) {return make_expr_call (*this,std::forward<Args>(args)...);}
#endif
}} // namespace triqs::clef
#endif
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