dft_tools/test/triqs/clef/lazy_method.cpp

#include "./common.hpp"
#include <triqs/clef.hpp>

struct Obj {
double v;                      // put something in it
Obj(double v_): v(v_){}        // constructor
Obj(Obj const &) = delete;    // a non copyable object, to illustrate that we do NOT copy...

// a method
double my_method(double x) const { return 2*x;}

// CLEF overload
TRIQS_CLEF_IMPLEMENT_LAZY_METHOD(Obj,my_method);

// Just to print itself nicely in the expressions
friend std::ostream & operator<<(std::ostream & out, Obj const & x) { return out<<"Obj";}
};

int main() {
Obj f(7);
triqs::clef::placeholder<1> x_; triqs::clef::placeholder<2> y_;

std::cout << "Clef expression     : "<<  f.my_method(y_) + 2*x_ << std::endl ;
std::cout << "Complete evaluation : "<< eval(f.my_method(x_) + 2*x_, x_=1) << std::endl ;
std::cout << "Partial evaluation  : "<< eval(f.my_method(y_) + 2*x_, y_=1) << std::endl ;
std::cout << "Complete evalution  : "<< eval(f.my_method(y_) + 2*x_, x_=3, y_=1) << std::endl ;
}