metaparse/doc/get_line.qbk
2015-07-19 09:53:35 +02:00

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[#get_line]
[section get_line]
[h1 Synopsis]
template <class SourcePosition>
struct get_line;
This is a [link lazy_metafunction lazy template metafunction].
[table Arguments
[[Name] [Type]]
[[`SourcePosition`] [[link source_position source position]]]
]
[h1 Description]
Returns the line of a source position.
[h1 Header]
#include <boost/metaparse/get_line.hpp>
[h1 Expression semantics]
For any `l`, `c` compile-time wrapped integral values and `ch` compile-time
wrapped character the following are equivalent
get_line<source_position<l, c, ch>>::type
l::type
[h1 Example]
#include <boost/metaparse/get_line.hpp>
#include <boost/metaparse/source_position.hpp>
#include <type_traits>
using namespace boost::metaparse;
struct returns_source_position
{
using type =
source_position<
std::integral_constant<int, 11>,
std::integral_constant<int, 13>,
std::integral_constant<char, 0>
>;
};
static_assert(
get_line<
source_position<
std::integral_constant<int, 11>,
std::integral_constant<int, 13>,
std::integral_constant<char, 0>
>
>::type::value == 11,
"It should return the line of a source position"
);
static_assert(
get_line<returns_source_position>::type::value == 11,
"It should support lazy evaluation"
);
[endsect]