68 lines
1.5 KiB
Plaintext
68 lines
1.5 KiB
Plaintext
[#range]
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[section range]
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[h1 Synopsis]
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template <class From, class To>
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struct range;
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This is a [link parser parser].
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[table Arguments
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[[Name] [Type]]
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[[`From`] [[link boxed_value boxed] character value]]
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[[`To`] [[link boxed_value boxed] character value]]
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]
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[h1 Description]
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`range` accepts one character in the range `[From..To]`. 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/range.hpp>
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[h1 Expression semantics]
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For any `A`, `B` wrapped characters the following are equivalent:
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range<A, B>
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accept_when<one_char, util::in_range<A, B>, errors::unexpected_character>
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[h1 Example]
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#include <boost/metaparse/range.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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#include <type_traits>
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using namespace boost::metaparse;
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using one_digit =
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range<std::integral_constant<char, '0'>, std::integral_constant<char, '9'>>;
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static_assert(
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!is_error<one_digit::apply<BOOST_METAPARSE_STRING("0"), start>>::type::value,
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"one_digit should accept a digit"
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);
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static_assert(
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is_error<one_digit::apply<BOOST_METAPARSE_STRING("x"), start>>::type::value,
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"one_digit should reject a value outside of ['0'..'9']"
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);
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static_assert(
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get_result<
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one_digit::apply<BOOST_METAPARSE_STRING("0"), start>
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>::type::value == '0',
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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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