mirror of
https://github.com/triqs/dft_tools
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430 lines
24 KiB
C++
430 lines
24 KiB
C++
/*******************************************************************************
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*
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* TRIQS: a Toolbox for Research in Interacting Quantum Systems
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*
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* Copyright (C) 2012 by O. Parcollet
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*
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* TRIQS is free software: you can redistribute it and/or modify it under the
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* terms of the GNU General Public License as published by the Free Software
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* Foundation, either version 3 of the License, or (at your option) any later
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* version.
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*
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* TRIQS is distributed in the hope that it will be useful, but WITHOUT ANY
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* WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
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* FOR A PARTICULAR PURPOSE. See the GNU General Public License for more
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* details.
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*
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* You should have received a copy of the GNU General Public License along with
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* TRIQS. If not, see <http://www.gnu.org/licenses/>.
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*
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******************************************************************************/
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#ifndef TRIQS_CLEF_CORE_H
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#define TRIQS_CLEF_CORE_H
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#include <triqs/utility/first_include.hpp>
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#include <tuple>
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#include <type_traits>
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#include <functional>
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#include <memory>
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#include <complex>
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#include <assert.h>
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#include <boost/preprocessor/stringize.hpp>
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#include <boost/preprocessor/repetition/repeat_from_to.hpp>
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#include <boost/preprocessor/repetition/enum.hpp>
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#include <boost/preprocessor/arithmetic/inc.hpp>
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#define TRIQS_CLEF_MAXNARGS 8
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namespace triqs { namespace clef {
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typedef unsigned long long ull_t;
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template<typename T> struct remove_cv_ref : std::remove_cv< typename std::remove_reference<T>::type> {};
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namespace tags { struct function_class{}; struct function{}; struct subscript{}; struct terminal{}; struct if_else{}; struct unary_op{}; struct binary_op{}; }
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/* ---------------------------------------------------------------------------------------------------
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* Placeholder and corresponding traits
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* --------------------------------------------------------------------------------------------------- */
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template<int i, typename T> struct pair {
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static constexpr int p = i;
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typedef typename remove_cv_ref <T>::type value_type;
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value_type const & r;
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value_type const & rhs() const { return r;}
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pair (T const & t) : r(t){}
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};
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template<int N> struct placeholder {
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static_assert( (N>=0) && (N<64) , "Placeholder number limited to [0,63]");
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static constexpr int index = N;
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template <typename RHS> pair<N,RHS> operator = (RHS const & rhs) { return pair<N,RHS>(rhs);}
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};
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template<typename T> struct is_placeholder : std::false_type {};
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template<int N> struct is_placeholder <placeholder <N> > : std::true_type {};
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template<typename... T> struct ph_set;
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template<typename T0, typename... T> struct ph_set<T0,T...>{static constexpr ull_t value= ph_set<T0>::value| ph_set<T...>::value;};
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template<typename T> struct ph_set<T> {static constexpr ull_t value= 0;};
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template<int N> struct ph_set<placeholder<N>> {static constexpr ull_t value= 1ull<<N;};
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template<int i, typename T> struct ph_set<pair<i,T> > : ph_set<placeholder<i>>{};
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/* ---------------------------------------------------------------------------------------------------
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* Detect if an object is a lazy expression
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* --------------------------------------------------------------------------------------------------- */
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template<typename... Args> struct is_any_lazy : std::false_type {};
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template<int N> struct is_any_lazy <placeholder <N> > : std::true_type {};
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template <typename T> struct is_any_lazy< T > : std::false_type {};
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template <typename T> struct is_any_lazy< T&& > : is_any_lazy<T> {};
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template <typename T> struct is_any_lazy< T& > : is_any_lazy<T> {};
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template <typename T> struct is_any_lazy< T const > : is_any_lazy<T> {};
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template<typename T, typename... Args> struct is_any_lazy<T, Args...> :
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std::integral_constant<bool, is_any_lazy<T>::value || is_any_lazy<Args...>::value> {};
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// a trait that checks the type are value i.e. no &, &&
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template<typename... T> struct has_no_ref : std::true_type {};
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template<typename T0, typename... T> struct has_no_ref<T0,T...> : std::integral_constant<bool, !(std::is_reference<T0>::value)&& has_no_ref<T...>::value> {};
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/* ---------------------------------------------------------------------------------------------------
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* Node of the expression tree
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* --------------------------------------------------------------------------------------------------- */
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template<typename Tag, typename... T> struct expr {
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static_assert( has_no_ref<T...>::value , "Internal error : expr childs can not be reference ");
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typedef std::tuple< T ...> childs_t;
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childs_t childs;
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expr(expr const & x) = default;
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expr(expr && x) : childs(std::move(x.childs)) {}
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template<typename... Args> explicit expr(Tag, Args&&...args) : childs(std::forward<Args>(args)...) {}
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template< typename Args >
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expr<tags::subscript, expr, typename remove_cv_ref<Args>::type > operator[](Args && args) const
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{ return expr<tags::subscript, expr, typename remove_cv_ref<Args>::type> (tags::subscript(), *this,std::forward<Args>(args));}
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template< typename... Args >
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expr<tags::function, expr, typename remove_cv_ref<Args>::type...> operator()(Args && ... args) const
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{ return expr<tags::function, expr, typename remove_cv_ref<Args>::type...>(tags::function(), *this,std::forward<Args>(args)...);}
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// only f(i,j) = expr is allowed, in case where f is a clef::function
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// otherwise use the << operator
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template<typename RHS, typename CH = childs_t>
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typename std::enable_if<std::is_base_of<tags::function_class, typename std::tuple_element<0,CH>::type>::value>::type
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operator= (RHS const & rhs) { *this << rhs;}
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template<typename RHS, typename CH = childs_t>
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typename std::enable_if<!std::is_base_of<tags::function_class, typename std::tuple_element<0,CH>::type>::value>::type
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operator= (RHS const & rhs) = delete;
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expr & operator= (expr const & ) = delete; // no ordinary copy
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};
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template<typename Tag, typename... T> struct ph_set< expr<Tag,T... > > : ph_set<T...> {};
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template<typename Tag, typename... T> struct is_any_lazy< expr<Tag,T... > >: std::true_type {};
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/* ---------------------------------------------------------------------------------------------------
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* The basic operations put in a template....
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* --------------------------------------------------------------------------------------------------- */
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template<typename Tag> struct operation;
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/// Terminal
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template<> struct operation<tags::terminal> { template<typename L> L operator()(L&& l) const { return std::forward<L>(l);} };
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/// Function call
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template<> struct operation<tags::function> {
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template<typename F, typename... Args> auto operator()(F const & f, Args const & ... args) const -> decltype(f(args...)) { return f(args...);}
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template<typename F, typename... Args> auto operator()(std::reference_wrapper<F> const &f, Args const & ... args) const -> decltype(f.get()(args...)) { return f.get()(args...);}
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};
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/// [ ] Call
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template<> struct operation<tags::subscript> {
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template<typename F, typename Args> auto operator()(F const & f, Args const & args) const -> decltype(f[args]) { return f[args];}
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template<typename F, typename Args> auto operator()(std::reference_wrapper<F> const &f, Args const & args) const -> decltype(f.get()[args]) { return f.get()[args];}
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};
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// all binary operators....
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#define TRIQS_CLEF_OPERATION(TAG,OP)\
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namespace tags { struct TAG : binary_op { static const char * name() { return BOOST_PP_STRINGIZE(OP);} };}\
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template<> struct operation<tags::TAG> {\
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template<typename L, typename R> auto operator()(L const & l, R const & r) const -> decltype(l OP r) { return l OP r;}\
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};\
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template<typename L, typename R>\
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typename std::enable_if<is_any_lazy<L,R>::value, expr<tags::TAG,typename remove_cv_ref<L>::type,typename remove_cv_ref<R>::type> >::type \
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operator OP (L && l, R && r) { return expr<tags::TAG,typename remove_cv_ref<L>::type,typename remove_cv_ref<R>::type> (tags::TAG(),std::forward<L>(l),std::forward<R>(r));}\
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TRIQS_CLEF_OPERATION(plus, +);
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TRIQS_CLEF_OPERATION(minus, -);
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TRIQS_CLEF_OPERATION(multiplies, *);
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TRIQS_CLEF_OPERATION(divides, /);
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TRIQS_CLEF_OPERATION(greater, >);
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TRIQS_CLEF_OPERATION(less, <);
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TRIQS_CLEF_OPERATION(leq, <=);
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TRIQS_CLEF_OPERATION(geq, >=);
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TRIQS_CLEF_OPERATION(eq, ==);
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#undef TRIQS_CLEF_OPERATION
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// all unary operators....
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#define TRIQS_CLEF_OPERATION(TAG,OP)\
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namespace tags { struct TAG : unary_op { static const char * name() { return BOOST_PP_STRINGIZE(OP);} };}\
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template<> struct operation<tags::TAG> {\
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template<typename L> auto operator()(L const & l) const -> decltype(OP l) { return OP l;}\
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};\
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template<typename L>\
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typename std::enable_if<is_any_lazy<L>::value, expr<tags::TAG,typename remove_cv_ref<L>::type> >::type \
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operator OP (L && l) { return expr<tags::TAG,typename remove_cv_ref<L>::type> (tags::TAG(),std::forward<L>(l));}\
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TRIQS_CLEF_OPERATION(negate, -);
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TRIQS_CLEF_OPERATION(loginot, !);
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#undef TRIQS_CLEF_OPERATION
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/// the only ternary node : expression if
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template<> struct operation<tags::if_else> {
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template<typename C, typename A, typename B> auto operator()(C const & c, A const & a, B const & b) const -> decltype((c?a:b)) {
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//static_assert(std::is_same<typename remove_cv_ref<A>::type,typename remove_cv_ref<B>::type>::value, "Expression if : evaluation type must be the same");
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return (c ? a: b);
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}
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};
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// operator is : if_else( Condition, A, B)
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template<typename C, typename A, typename B>
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expr<tags::if_else,typename remove_cv_ref<C>::type,typename remove_cv_ref<A>::type,typename remove_cv_ref<B>::type>
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if_else(C && c, A && a, B && b) {
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return expr<tags::if_else,typename remove_cv_ref<C>::type,typename remove_cv_ref<A>::type,typename remove_cv_ref<B>::type>
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(tags::if_else(),std::forward<C>(c),std::forward<A>(a),std::forward<B>(b));}
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/* ---------------------------------------------------------------------------------------------------
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* Evaluation of the expression tree.
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* --------------------------------------------------------------------------------------------------- */
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template<typename Tag, bool IsLazy, typename... Args> struct operation2;
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template<typename Tag, typename... Args> struct operation2<Tag, true, Args...> {
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typedef expr<Tag,typename remove_cv_ref<Args>::type ...> rtype;
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rtype operator()(Args && ... args) const {return rtype (Tag(), std::forward<Args>(args)...);}
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};
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template<typename Tag, typename... Args> struct operation2<Tag, false, Args...> {
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typedef typename std::remove_reference<typename std::result_of<operation<Tag>(Args...)>::type>::type rtype;
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// remove the reference because of ternary if_else in which decltype returns a ref...
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rtype operator()(Args const & ... args) const {return operation<Tag>()(args...); }
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};
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// Generic case : do nothing (for the leaf of the tree except placeholder)
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template<typename T, typename ... Pairs> struct evaluator{
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typedef T rtype;
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rtype operator()( T const & k, Pairs const &... pairs) {return k;}
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};
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// placeholder
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template<int N, int i, typename T, typename... Pairs> struct evaluator< placeholder<N>, pair<i,T>, Pairs... > {
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typedef evaluator< placeholder<N>, Pairs...> eval_t;
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typedef typename eval_t::rtype rtype;
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rtype operator()(placeholder<N>, pair<i,T> const &, Pairs const& ... pairs) { return eval_t()(placeholder<N>(), pairs...);}
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};
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template<int N, typename T, typename... Pairs> struct evaluator< placeholder<N>, pair<N,T>, Pairs... > {
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typedef typename pair<N,T>::value_type const & rtype;
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rtype operator()(placeholder<N>, pair<N,T> const & p, Pairs const& ...) { return p.r;}
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};
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// general expr node
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template<typename Tag, typename... Childs, typename... Pairs> struct evaluator<expr<Tag, Childs...>, Pairs...> {
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typedef operation2<Tag, is_any_lazy<typename evaluator<Childs, Pairs...>::rtype... >::value, typename evaluator<Childs, Pairs...>::rtype... > OPTYPE;
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typedef typename OPTYPE::rtype rtype;
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#define AUX(z,p,unused) eval(std::get<p>(ex.childs),pairs...)
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#define IMPL(z, NN, unused) \
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template< int arity = sizeof...(Childs)>\
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typename std::enable_if< arity==NN, rtype>::type\
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operator()(expr<Tag, Childs...> const & ex, Pairs const & ... pairs) const\
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{ return OPTYPE()(BOOST_PP_ENUM(NN,AUX,nil));}
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BOOST_PP_REPEAT_FROM_TO(1,BOOST_PP_INC(TRIQS_CLEF_MAXNARGS), IMPL, nil);
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#undef AUX
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#undef IMPL
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};
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// The general eval function for expressions
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template<typename T, typename... Pairs>
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typename evaluator<T,Pairs...>::rtype
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eval (T const & ex, Pairs const &... pairs) { return evaluator<T, Pairs...>()(ex, pairs...); }
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#ifdef TRIQS_SHORT_CIRCUIT_NOT_IMPLEMENTED
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// A short circuit if intersection of ph and is 0, no need to evaluate the whole tree......
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template<typename T, typename... Pairs>
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template<typename Tag, typename... Childs, typename... Pairs>
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typename std::enable_if< (ph_set<Childs...>::value & ph_set<Pairs...>::value) !=0, typename evaluator<expr<Tag,Childs...>,Pairs...>::rtype > ::type
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eval (expr<Tag,Childs...> const & ex, Pairs const &... pairs) { return evaluator<expr<Tag,Childs...>, Pairs...>()(ex, pairs...); }
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template<typename Tag, typename... Childs, typename... Pairs>
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typename std::enable_if< (ph_set<Childs...>::value & ph_set<Pairs...>::value) ==0, expr<Tag,Childs...> > ::type
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eval (expr<Tag,Childs...> const & ex, Pairs const &... pairs) { return ex; }
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#endif
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/* ---------------------------------------------------------------------------------------------------
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* make_function : transform an expression to a function
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* --------------------------------------------------------------------------------------------------- */
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template< typename Expr, int... Is> struct make_fun_impl {
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Expr ex; // keep a copy of the expression
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make_fun_impl(Expr const & ex_) : ex(ex_) {}
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// gcc 4.6 crashes (!!!) on the first variant
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#define TRIQS_WORKAROUND_GCC46BUG
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#ifndef TRIQS_WORKAROUND_GCC46BUG
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template<typename... Args>
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typename evaluator<Expr,pair<Is,Args>...>::rtype
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operator()(Args const &... args) const
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{ return evaluator<Expr,pair<Is,Args>...>() ( ex, pair<Is,Args>(args)...); }
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#else
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template<typename... Args> struct __eval {
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typedef evaluator<Expr,pair<Is,Args>...> eval_t;
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typedef typename eval_t::rtype rtype;
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rtype operator()(Expr const &ex , Args const &... args) const { return eval_t() ( ex, pair<Is,Args>(args)...); }
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};
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template<typename... Args>
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typename __eval<Args...>::rtype operator()(Args const &... args) const { return __eval<Args...>() ( ex, args...); }
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#endif
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};
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template<ull_t x, int... Is> struct ph_filter;
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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));};
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template<ull_t x> struct ph_filter<x> { static constexpr ull_t value = x; };
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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;};
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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>{};
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template< typename Expr, int... Is,typename... Pairs> struct evaluator<make_fun_impl<Expr,Is...>, Pairs...> {
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typedef evaluator<Expr,Pairs...> e_t;
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typedef make_fun_impl<typename e_t::rtype, Is...> rtype;
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rtype operator()(make_fun_impl<Expr,Is...> const & f, Pairs const & ... pairs) const { return rtype( e_t()(f.ex, pairs...));}
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};
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template< typename Expr, typename ... Phs>
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make_fun_impl<typename std::remove_cv<typename std::remove_reference<Expr>::type>::type,Phs::index...>
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make_function(Expr && ex, Phs...) { return {ex}; }
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namespace result_of {
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template< typename Expr, typename ... Phs> struct make_function {
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typedef make_fun_impl<typename std::remove_cv<typename std::remove_reference<Expr>::type>::type,Phs::index...> type;
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};
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}
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/* --------------------------------------------------------------------------------------------------
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* make_function
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* x_ >> expression is the same as make_function(expression,x)
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* --------------------------------------------------------------------------------------------------- */
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template <int N, typename Expr>
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make_fun_impl<Expr,N > operator >> ( placeholder<N> p, Expr&& ex) { return {ex}; }
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/* ---------------------------------------------------------------------------------------------------
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* Auto assign for ()
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* --------------------------------------------------------------------------------------------------- */
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// by default it is deleted = not implemented : every class has to define it...
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template<typename T, typename F> void triqs_clef_auto_assign (T,F) = delete;
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// remove the ref_wrapper, terminal ...
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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));}
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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));}
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// auto assign of an expr ? (for chain calls) : just reuse the same operator
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template<typename Tag, typename... Childs, typename RHS>
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void triqs_clef_auto_assign (expr<Tag,Childs...> && ex, RHS const & rhs) { ex << rhs;}
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template<typename Tag, typename... Childs, typename RHS>
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void triqs_clef_auto_assign (expr<Tag,Childs...> const & ex, RHS const & rhs) { ex << rhs;}
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// The case A(x_,y_) = RHS : we form the function (make_function) and call auto_assign (by ADL)
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template<typename F, typename RHS, int... Is>
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void operator<<(expr<tags::function, F, placeholder<Is>...> && ex, RHS && rhs) {
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triqs_clef_auto_assign(std::get<0>(ex.childs), make_function(std::forward<RHS>(rhs), placeholder<Is>()...));
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}
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template<typename F, typename RHS, int... Is>
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void operator<<(expr<tags::function, F, placeholder<Is>...> const & ex, RHS && rhs) {
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triqs_clef_auto_assign(std::get<0>(ex.childs), make_function(std::forward<RHS>(rhs), placeholder<Is>()...));
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}
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// any other case e.g. f(x_+y_) = RHS etc .... which makes no sense : compiler will stop
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template<typename F, typename RHS, typename... T>
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void operator<<(expr<tags::function, F, T...> && ex, RHS && rhs) = delete;
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template<typename F, typename RHS, typename... T>
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void operator<<(expr<tags::function, F, T...> const & ex, RHS && rhs) = delete;
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/* ---------------------------------------------------------------------------------------------------
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* Auto assign for []
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* --------------------------------------------------------------------------------------------------- */
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// by default it is deleted = not implemented : every class has to define it...
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template<typename T, typename F> void triqs_clef_auto_assign_subscript (T,F) = delete;
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// remove the ref_wrapper, terminal ...
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template<typename T, typename F> void triqs_clef_auto_assign_subscript (std::reference_wrapper<T> R ,F && f)
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{ triqs_clef_auto_assign_subscript(R.get(),std::forward<F>(f));}
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template<typename T, typename F> void triqs_clef_auto_assign_subscript (expr<tags::terminal,T> const & t,F && f)
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{ triqs_clef_auto_assign_subscript(std::get<0>(t.childs),std::forward<F>(f));}
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// auto assign of an expr ? (for chain calls) : just reuse the same operator
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template<typename Tag, typename... Childs, typename RHS>
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void triqs_clef_auto_assign_subscript (expr<Tag,Childs...> const & ex, RHS const & rhs) { ex << rhs;}
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// Same thing for the [ ]
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template<typename F, typename RHS, int... Is>
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void operator<<(expr<tags::subscript, F, placeholder<Is>...> const & ex, RHS && rhs) {
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triqs_clef_auto_assign_subscript(std::get<0>(ex.childs), make_function(std::forward<RHS>(rhs), placeholder<Is>()...));
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}
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template<typename F, typename RHS, typename... T>
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void operator<<(expr<tags::subscript, F, T...> const & ex, RHS && rhs) = delete;
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/* --------------------------------------------------------------------------------------------------
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* Create a terminal node of an object. The reference is wrapped in a reference_wrapper...
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* --------------------------------------------------------------------------------------------------- */
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template<typename T> expr<tags::terminal,typename remove_cv_ref<T>::type >
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make_expr(T && x){ return expr<tags::terminal,typename remove_cv_ref<T>::type >(tags::terminal(), std::forward<T>(x));}
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template<typename T> auto lazy (T && x) -> decltype (make_expr(std::ref(x))) { return make_expr(std::ref(x)); }
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/* --------------------------------------------------------------------------------------------------
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* Create a call node of an object
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* The object can be kept as a : a ref, a copy, a view
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* --------------------------------------------------------------------------------------------------- */
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namespace result_of {
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template< typename Obj, typename... Args > struct make_expr_call :
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std::enable_if< is_any_lazy<Args...>::value, expr<tags::function,typename remove_cv_ref<Obj>::type, typename remove_cv_ref<Args>::type ...> > {};
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}
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template< typename Obj, typename... Args >
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typename result_of::make_expr_call<Obj,Args...>::type
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make_expr_call(Obj&& obj, Args &&... args)
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{ return typename result_of::make_expr_call<Obj,Args...>::type (tags::function(),std::forward<Obj>(obj), std::forward<Args>(args)...);}
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/* --------------------------------------------------------------------------------------------------
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* function class : stores any expression polymorphically
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* f(x_,y_ ) = an expression associates this expression dynamically to f, which
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* can then be used as a std::function of the same signature...
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* --------------------------------------------------------------------------------------------------- */
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template<typename F> class function;
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template<typename ReturnType, typename... T> class function<ReturnType(T...)> : tags::function_class {
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typedef std::function<ReturnType(T...)> std_function_type;
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mutable std::shared_ptr <void> _exp; // CLEAN THIS MUTABLE ?
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mutable std::shared_ptr < std_function_type > _fnt_ptr;
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public:
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function():_fnt_ptr(new std_function_type ()){}
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template<typename Expr, typename... X>
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explicit function(Expr const & _e, X... x) : _exp(new Expr(_e)),_fnt_ptr(new std_function_type(make_function(_e, x...))){}
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ReturnType operator()(T const &... t) const { return (*_fnt_ptr)(t...);}
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template< typename... Args>
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typename triqs::clef::result_of::make_expr_call<function,Args...>::type
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operator()( Args&&... args ) const { return triqs::clef::make_expr_call (*this,args...);}
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template<typename RHS> friend void triqs_clef_auto_assign (function const & x, RHS rhs) {
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* (x._fnt_ptr) = std_function_type (rhs);
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x._exp = std::shared_ptr <void> (new typename std::remove_cv<decltype(rhs.ex)>::type (rhs.ex));
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}
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};
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/* --------------------------------------------------------------------------------------------------
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* The macro to make any function lazy
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* TRIQS_CLEF_MAKE_FNT_LAZY (Arity,FunctionName ) : creates a new function in the triqs::lazy namespace
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* taking expressions (at least one argument has to be an expression)
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* The lookup happens by ADL, so IT MUST BE USED IN THE triqs::lazy namespace
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* --------------------------------------------------------------------------------------------------- */
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#define TRIQS_CLEF_MAKE_FNT_LAZY(name)\
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struct name##_lazy_impl { \
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template<typename... A> auto operator()(A&&... a) const -> decltype (name(std::forward<A>(a)...)) { return name(std::forward<A>(a)...); }\
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};\
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template< typename... A> \
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typename triqs::clef::result_of::make_expr_call<name##_lazy_impl,A...>::type name( A&& ... a) { return make_expr_call(name##_lazy_impl(),a...);}
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}} // namespace triqs::clef
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#endif
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