Parser Combinator

An experimental parser combinator library written in C++23. Fully support constexpr parsing in compile time.

Example

constexpr auto ipv4 = [](
    uint8_t a, uint8_t b, uint8_t c, uint8_t d) {
    return (a << 24) | (b << 16) | (c << 8) | d;
};

constexpr auto octet = integer<uint8_t>;
constexpr auto ipv4_addr = eof(sepby<4>(octet, dot));
constexpr auto to_ipv4 = ipv4_addr | to([](auto&& result) {
    auto [a, b, c, d] = result;
    return ipv4( a, b, c, d );
});
static_assert(to_ipv4("192.168.1.1") == ipv4(192, 168, 1, 1));

Monadic

• to converts the parser's result to anther type
• map maps a function over the result of a parser
• or_else applies a function over the input if the parser failed
• and_then applies a function over the result of a parser

Combinator

• success consumes no input and always succeeds with given value.
• predict return the result of the parser if it satisfies a predictate
• seq (operator+) matches a sequence of parsers in the defined order. Return a std::tuple of the two return value of the parsers.
• choice (operator||) tries to apply the parsers in order until one of them succeeds.
• left matches two parsers and accepts the result from the left side.
• right matches two parsers and accepts the result from the right side.
• between matches three parsers and accepts the result from the middle one.
• many matches a parser multiple times, can be a matched 0 times. Return a std::vector of the return value of the parser.
• many1 matches a parser multiple times at least one time. Return a std::vector of the return value of the parser.
• many<> matches a parser in a fixed amount of times. Return a std::array of the return value of the parser.
• sepby matches a parser separated by another parser, can be a matched 0 times.
• sepby1 matches a parser separated by another parser at least one time.
• sepby<> matches a parser separated by another parser in a fixed amount of times.
• eof matches the of the input

Character

• any matches any character
• satisfy matches one character if it satisfies a predicate.
• range matches one character in the range of characters.
• one_of matches the character in the list of characters.
• none_of matches the character not in the list of characters.
• digit matches one numerical character: 0-9.
• octdigit matches one octal numerical character: 0-7.
• hexdigit matches one hexadecimal numerical character: 0-9, a-f, A-F.
• lower matches one lowercase alphabetic character: a-z.
• upper matches one uppercase alphabetic character: A-Z.
• alpha matches one alphabet character: a-z, A-Z.
• alphanum matches one numerical or alphabetic character: 0-9, a-z, A-Z.
• sign matches one sign character: -, +.
• space matches one whitespace character
• dot matches one semi character: ..
• semi matches one semi character: ;.
• comma matches one comma character: ,.
• colon matches one colon character: :.
• quota matches one quota character: ".
• escape matches one escaped character: ", \, /, \b, \f, \n, \r, \t.

Token

• symbol matches a specific string.
• octal matches a octal number.
• decimal matches a decimal number.
• hexadecimal matches a hexadecimal number.
• squares matches a parser enclosed in squares: [].
• brackets matches a parser enclosed in brackets: {}.
• parentheses matches a parser enclosed in parentheses: ().

Compiler support

• MSVC 19.34+ /std::c++latest