What this library can do

ctre::match<"REGEX">(subject);// C++20"REGEX"_ctre.match(subject);// C++17 + N3599 extension

Unknown character escape behaviour

Basic API

// look if whole input matches the regex:template<fixed_string regex>autoctre::match(auto Range &&) -> regex_results;template<fixed_string regex>autoctre::match(auto First &&,auto Last &&) -> regex_results;// look if input contains match somewhere inside of itself:template<fixed_string regex>autoctre::search(auto Range &&) -> regex_results;template<fixed_string regex>autoctre::search(auto First &&,auto Last &&) -> regex_results;// check if input starts with match (but doesn't need to match everything):template<fixed_string regex>autoctre::starts_with(auto Range &&) -> regex_results;template<fixed_string regex>autoctre::starts_with(auto First &&,auto Last &&) -> regex_results;// result type is deconstructible into a structured bindingstemplate<...>structregex_results {operatorbool()const;// if it's a matchautoto_view()const -> std::string_view;// also view()autoto_string()const -> std::string;// also str()operatorstd::string_view()const;// also supports all char variantsexplicitoperatorstd::string()const;// also size(), begin(), end(), data()size_tcount()const;// number of capturestemplate<size_t Id>const captured_content &get()const;// provide specific capture, whole regex_results is implicit capture 0};

Range outputting API

// search for regex in input and return each occurrence, ignoring rest:template<fixed_string regex>autoctre::range(auto Range &&) -> range of regex_result;template<fixed_string regex>autoctre::range(auto First &&,auto Last &&) -> range of regex_result;// return range of each match, stopping at something which can't be matchedtemplate<fixed_string regex>autoctre::tokenize(auto Range &&) -> range of regex_result;template<fixed_string regex>autoctre::tokenize(auto First &&,auto Last &&) -> range of regex_result;// return parts of the input split by the regex, returning it as part of content of the implicit zero capture (other captures are not changed, you can use it to access how the values were split):template<fixed_string regex>autoctre::split(auto Range &&) -> regex_result;template<fixed_string regex>autoctre::split(auto First &&,auto Last &&) -> range of regex_result;

Functors

auto matcher = ctre::match<"regex">;if (matcher(input)) ...

Possible subjects (inputs)

Unicode support

Supported compilers

Template UDL syntax

constexprautomatch(std::string_view sv)noexcept {usingnamespacectre::literals;return"h.*"_ctre.match(sv);}

C++17 syntax

staticconstexprauto pattern = ctll::fixed_string{"h.*" };constexprautomatch(std::string_view sv)noexcept {return ctre::match<pattern>(sv);}

C++20 syntax

constexprautomatch(std::string_view sv)noexcept {return ctre::match<"h.*">(sv);}

Examples

Extracting number from input

std::optional<std::string_view>extract_number(std::string_view s)noexcept {if (auto m = ctre::match<"[a-z]+([0-9]+)">(s)) {return m.get<1>().to_view();    }else {return std::nullopt;    }}

Extracting values from date

structdate { std::string_view year; std::string_view month; std::string_view day; };std::optional<date>extract_date(std::string_view s)noexcept {usingnamespacectre::literals;if (auto [whole, year, month, day] = ctre::match<"(\\d{4})/(\\d{1,2})/(\\d{1,2})">(s); whole) {return date{year, month, day};    }else {return std::nullopt;    }}// static_assert(extract_date("2018/08/27"sv).has_value());// static_assert((*extract_date("2018/08/27"sv)).year == "2018"sv);// static_assert((*extract_date("2018/08/27"sv)).month == "08"sv);// static_assert((*extract_date("2018/08/27"sv)).day == "27"sv);

Using captures

auto result = ctre::match<"(?<year>\\d{4})/(?<month>\\d{1,2})/(?<day>\\d{1,2})">(s);return date{result.get<"year">(), result.get<"month">, result.get<"day">};// or in C++ emulation, but the object must have a linkagestaticconstexpr ctll::fixed_string year ="year";staticconstexpr ctll::fixed_string month ="month";staticconstexpr ctll::fixed_string day ="day";return date{result.get<year>(), result.get<month>(), result.get<day>()};// or use numbered access// capture 0 is the whole matchreturn date{result.get<1>(), result.get<2>(), result.get<3>()};

Lexer

enumclasstype {    unknown, identifier, number};structlex_item {    type t;    std::string_view c;};std::optional<lex_item>lexer(std::string_view v)noexcept {if (auto [m,id,num] = ctre::match<"([a-z]+)|([0-9]+)">(v); m) {if (id) {return lex_item{type::identifier, id};        }elseif (num) {return lex_item{type::number, num};        }    }return std::nullopt;}

Range over input

auto input ="123,456,768"sv;for (auto match: ctre::search_all<"([0-9]+),?">(input))    std::cout << std::string_view{match.get<0>()} <<"\n";

Unicode

#include<ctre-unicode.hpp>#include<iostream>// needed if you want to output to the terminalstd::string_viewcast_from_unicode(std::u8string_view input)noexcept {returnstd::string_view(reinterpret_cast<constchar *>(input.data()), input.size());}intmain() {usingnamespacestd::literals;    std::u8string_view original =u8"Tu es un génie"sv;for (auto match: ctre::search_all<"\\p{Letter}+">(original))        std::cout <<cast_from_unicode(match) << std::endl;return0;}

Installing ctre using vcpkg

git clone https://github.com/Microsoft/vcpkg.gitcd vcpkg./bootstrap-vcpkg.sh./vcpkg integrate install./vcpkg install ctre

Running tests (for developers)