69 lines
1.4 KiB
Plaintext
69 lines
1.4 KiB
Plaintext
[#range_c]
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[section range_c]
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[h1 Synopsis]
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template <char From, char To>
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struct range_c;
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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`] [character value]]
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[[`To`] [character value]]
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]
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[h1 Description]
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`range_c` 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_c.hpp>
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[h1 Expression semantics]
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For any `A`, `B` characters the following are equivalent:
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range_c<A, B>
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accept_when<
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one_char,
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util::in_range_c<char, A, B>,
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errors::unexpected_character
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>
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[h1 Example]
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#include <boost/metaparse/range_c.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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using one_digit = range_c<'0', '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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