123456789101112131415161718192021222324252627282930313233343536373839404142434445464748495051525354555657585960616263646566676869707172737475767778798081828384858687 |
- [#sequence_apply]
- [section sequence_apply]
- [h1 Synopsis]
- template <template <class, ..., class> class T, class P1, ..., class Pn>
- struct sequence_applyn;
- This is a [link parser_combinator parser combinator].
- [table Arguments
- [[T] [Template class taking `n` arguments]]
- [[`P1`..`Pn`] [[link parser parser]s]]
- ]
- [h1 Description]
- It applies the `P1` ... `Pn` [link parser parser]s on the input in order. When
- all of them succeed, the result of parsing with `sequence_applyn` is the `T`
- template class instantiated with the results of the `P1` ... `Pn`
- [link parser parser]s. When any of the `P1` ... `Pn` [link parser parser]s
- reject the input, the error is propagated.
- `n` has to be in the `[1..BOOST_METAPARSE_LIMIT_SEQUENCE_SIZE)` range.
- [h1 Header]
- #include <boost/metaparse/sequence_apply.hpp>
- [h1 Expression semantics]
- For any `n > 0`, `p1` ... `pn` [link parser parser]s, `t` template class with
- `n` `class` arguments, `s` compile-time string and `pos` source position the
- following are equivalent:
- sequence_apply<t, p1, ..., pn>::apply<s, pos>::type
- when [link sequence `sequence`]`<p1, ..., pn>` accepts the input:
- return_<
- t<
- mpl::at_c<0, get_result<sequence<p1,...,pn>::apply<s, pos>>::type>::type,
- ...
- mpl::at_c<n, get_result<sequence<p1,...,pn>::apply<s, pos>>::type>::type,
- >
- >::apply<s, pos>::type
- when [link sequence `sequence`]`<p1, ..., pn>` rejects the input:
- sequence<p1, ..., pn>::apply<s, pos>::type
-
- [h1 Example]
- #include <boost/metaparse/sequence_apply.hpp>
- #include <boost/metaparse/int_.hpp>
- #include <boost/metaparse/middle_of.hpp>
- #include <boost/metaparse/lit_c.hpp>
- #include <boost/metaparse/start.hpp>
- #include <boost/metaparse/string.hpp>
- #include <boost/metaparse/get_result.hpp>
-
- #include <boost/type_traits/is_same.hpp>
-
- using namespace boost::metaparse;
-
- template <int Real, int Imaginary>
- struct complex_c { typedef complex_c type; };
- template <class Real, class Imaginary>
- struct complex : complex_c<Real::type::value, Imaginary::type::value> {};
- typedef
- sequence_apply2<complex, int_, middle_of<lit_c<'+'>, int_, lit_c<'i'>>>
- complex_parser;
-
- static_assert(
- boost::is_same<
- complex_c<1, 2>,
- get_result<
- complex_parser::apply<BOOST_METAPARSE_STRING("1+2i"), start>
- >::type::type
- >::type::value,
- "the result of parsing should be the list of digit values"
- );
- [endsect]
|