8 This is a [link parser parser].
12 `spaces` accepts any number of whitespace characters. It requires at least one
17 #include <boost/metaparse/spaces.hpp>
19 [h1 Expression semantics]
29 #include <boost/metaparse/spaces.hpp>
30 #include <boost/metaparse/start.hpp>
31 #include <boost/metaparse/string.hpp>
32 #include <boost/metaparse/is_error.hpp>
33 #include <boost/metaparse/get_remaining.hpp>
35 #include <type_traits>
37 using namespace boost::metaparse;
41 BOOST_METAPARSE_STRING("foo"),
42 get_remaining<spaces::apply<BOOST_METAPARSE_STRING(" foo"), start>>::type
44 "it should consume all whitespaces at the beginning of the input"
48 is_error<spaces::apply<BOOST_METAPARSE_STRING("x"), start>>::type::value,
49 "it should return an error when the input does not begin with a whitespace"