56 lines
1.1 KiB
Plaintext
56 lines
1.1 KiB
Plaintext
[#letter]
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[section letter]
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[h1 Synopsis]
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struct letter;
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This is a [link parser parser].
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[h1 Description]
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Parser accepting one character in the range `a-z` or `A-Z`. The result of the
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parser is the accepted character.
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[h1 Header]
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#include <boost/metaparse/letter.hpp>
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[h1 Expression semantics]
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The following are equivalent:
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letter
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accept_when<one_char, util::is_letter<>, error::letter_expected>
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[h1 Example]
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#include <boost/metaparse/letter.hpp>
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#include <boost/metaparse/start.hpp>
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#include <boost/metaparse/string.hpp>
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#include <boost/metaparse/is_error.hpp>
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#include <boost/metaparse/get_result.hpp>
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using namespace boost::metaparse;
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static_assert(
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!is_error<letter::apply<BOOST_METAPARSE_STRING("a"), start>>::type::value,
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"letter should accept a letter"
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);
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static_assert(
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is_error<letter::apply<BOOST_METAPARSE_STRING("0"), start>>::type::value,
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"letter should reject a digit"
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);
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static_assert(
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get_result<
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letter::apply<BOOST_METAPARSE_STRING("z"), start>
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>::type::value == 'z',
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"the result of parsing should be the character value"
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);
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[endsect]
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