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- [#is_whitespace_c]
- [section is_whitespace_c]
- [h1 Synopsis]
- namespace util
- {
- template <char C>
- struct is_whitespace_c;
- }
- This is a template class similar to a [link metafunction template metafunction]
- but taking a `char` value as argument.
- [table Arguments
- [[Name] [Type]]
- [[`D`] [`char` value]]
- ]
- [h1 Description]
- Checks if `C` is a whitespace character. Returns a boxed boolean value.
- [h1 Header]
- #include <boost/metaparse/util/is_whitespace_c.hpp>
- [h1 Expression semantics]
- The following expressions are equivalent:
- is_whitespace_c<' '>::type
- boost::mpl::true_
- is_whitespace_c<'\t'>::type
- boost::mpl::true_
- is_whitespace_c<'\r'>::type
- boost::mpl::true_
- is_whitespace_c<'\n'>::type
- boost::mpl::true_
- For any `c` character other than the above listed ones the following are
- equivalent:
- is_whitespace_c<c>::type
- boost::mpl::false_
- [h1 Example]
- #include <boost/metaparse/util/is_whitespace_c.hpp>
-
- #include <type_traits>
-
- using namespace boost::metaparse;
-
- static_assert(
- util::is_whitespace_c<' '>::type::value,
- "a space should be a whitespace character"
- );
-
- static_assert(
- !util::is_whitespace_c<'0'>::type::value,
- "a number should not be a whitespace character"
- );
-
- [endsect]
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