template<template< int > class Operation, int first, int last>
class Dune::ForLoop< Operation, first, last >
A static loop using TMP.
The ForLoop takes a
template<int i> class Operation
template argument with a static apply method which is called for i=first...last (first<=last are int template arguments). A specialization for class template class Operation for i=first or i=last is not required. The class Operation must provide a static void function apply(...). Arguments (as references) can be passed through the ForLoop to this function.
It is possible to pass a subclass to the ForLoop (since no specialization is needed).
Example of usage:
template<class Tuple>
struct PrintTupleTypes
{
template <int i>
struct Operation
{
template<class Stream>
static void apply(Stream &stream, const std::string &prefix)
{
stream << prefix << i << ": "
<< className<typename tuple_element<i, Tuple>::type>()
<< std::endl;
}
};
template<class Stream>
static void print(Stream &stream, const std::string &prefix)
{
std::string extended_prefix = prefix+" ";
stream << prefix << "tuple<" << std::endl;
ForLoop<Operation, 0, tuple_size<Tuple>::value-1>::
apply(stream, extended_prefix);
stream << prefix << ">" << std::endl;
}
};
- Note
- Since Dune 2.4, ForLoop uses variadic templates and perfect forwarding and thus supports arbitrary numbers of arguments to apply(), which can be any combination of lvalues and rvalues.