CLI11.h

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// CLI11: Version 2.3.1
// Originally designed by Henry Schreiner
// https://github.com/CLIUtils/CLI11
//
// This is a standalone header file generated by MakeSingleHeader.py in CLI11/scripts
// from: v2.3.1
//
// CLI11 2.3.1 Copyright (c) 2017-2022 University of Cincinnati, developed by Henry
// Schreiner under NSF AWARD 1414736. All rights reserved.
//
// Redistribution and use in source and binary forms of CLI11, with or without
// modification, are permitted provided that the following conditions are met:
//
// 1. Redistributions of source code must retain the above copyright notice, this
//    list of conditions and the following disclaimer.
// 2. Redistributions in binary form must reproduce the above copyright notice,
//    this list of conditions and the following disclaimer in the documentation
//    and/or other materials provided with the distribution.
// 3. Neither the name of the copyright holder nor the names of its contributors
//    may be used to endorse or promote products derived from this software without
//    specific prior written permission.
//
// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
// ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
// WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
// DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR
// ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
// (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
// LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON
// ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
// SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

// This header is not meant to be included in a .h file, to guard against
// conflicts if a program includes their own CLI11 header and then transitively
// includes this header.
#ifdef PXR_CLI11_H
#error This file should only be included once in any given source (.cpp) file.
#endif
#define PXR_CLI11_H

#pragma once

// Standard combined includes:
#include <functional>
#include <locale>
#include <cstdint>
#include <iomanip>
#include <memory>
#include <exception>
#include <stdexcept>
#include <string>
#include <vector>
#include <iterator>
#include <algorithm>
#include <sstream>
#include <cmath>
#include <type_traits>
#include <limits>
#include <set>
#include <utility>
#include <map>
#include <iostream>
#include <numeric>
#include <fstream>
#include <tuple>

#include "pxr/pxr.h"

// Guard against possible conflicts if this header is included in the
// same file as another CLI11 header.
#ifdef CLI11_VERSION
#error This file cannot be included alongside a different CLI11 header.
#endif

#define CLI11_VERSION_MAJOR 2
#define CLI11_VERSION_MINOR 3
#define CLI11_VERSION_PATCH 1
#define CLI11_VERSION "2.3.1"




// The following version macro is very similar to the one in pybind11
#if !(defined(_MSC_VER) && __cplusplus == 199711L) && !defined(__INTEL_COMPILER)
#if __cplusplus >= 201402L
#define CLI11_CPP14
#if __cplusplus >= 201703L
#define CLI11_CPP17
#if __cplusplus > 201703L
#define CLI11_CPP20
#endif
#endif
#endif
#elif defined(_MSC_VER) && __cplusplus == 199711L
// MSVC sets _MSVC_LANG rather than __cplusplus (supposedly until the standard is fully implemented)
// Unless you use the /Zc:__cplusplus flag on Visual Studio 2017 15.7 Preview 3 or newer
#if _MSVC_LANG >= 201402L
#define CLI11_CPP14
#if _MSVC_LANG > 201402L && _MSC_VER >= 1910
#define CLI11_CPP17
#if _MSVC_LANG > 201703L && _MSC_VER >= 1910
#define CLI11_CPP20
#endif
#endif
#endif
#endif

#if defined(CLI11_CPP14)
#define CLI11_DEPRECATED(reason) [[deprecated(reason)]]
#elif defined(_MSC_VER)
#define CLI11_DEPRECATED(reason) __declspec(deprecated(reason))
#else
#define CLI11_DEPRECATED(reason) __attribute__((deprecated(reason)))
#endif

// GCC < 10 doesn't ignore this in unevaluated contexts
#if !defined(CLI11_CPP17) ||                                                                                           \
    (defined(__GNUC__) && !defined(__llvm__) && !defined(__INTEL_COMPILER) && __GNUC__ < 10 && __GNUC__ > 4)
#define CLI11_NODISCARD
#else
#define CLI11_NODISCARD [[nodiscard]]
#endif

/** detection of rtti */
#ifndef CLI11_USE_STATIC_RTTI
#if(defined(_HAS_STATIC_RTTI) && _HAS_STATIC_RTTI)
#define CLI11_USE_STATIC_RTTI 1
#elif defined(__cpp_rtti)
#if(defined(_CPPRTTI) && _CPPRTTI == 0)
#define CLI11_USE_STATIC_RTTI 1
#else
#define CLI11_USE_STATIC_RTTI 0
#endif
#elif(defined(__GCC_RTTI) && __GXX_RTTI)
#define CLI11_USE_STATIC_RTTI 0
#else
#define CLI11_USE_STATIC_RTTI 1
#endif
#endif

/** Inline macro **/
#ifdef CLI11_COMPILE
#define CLI11_INLINE
#else
#define CLI11_INLINE inline
#endif



// C standard library
// Only needed for existence checking
#if defined CLI11_CPP17 && defined __has_include && !defined CLI11_HAS_FILESYSTEM
#if __has_include(<filesystem>)
// Filesystem cannot be used if targeting macOS < 10.15
#if defined __MAC_OS_X_VERSION_MIN_REQUIRED && __MAC_OS_X_VERSION_MIN_REQUIRED < 101500
#define CLI11_HAS_FILESYSTEM 0
#elif defined(__wasi__)
// As of wasi-sdk-14, filesystem is not implemented
#define CLI11_HAS_FILESYSTEM 0
#else
#include <filesystem>
#if defined __cpp_lib_filesystem && __cpp_lib_filesystem >= 201703
#if defined _GLIBCXX_RELEASE && _GLIBCXX_RELEASE >= 9
#define CLI11_HAS_FILESYSTEM 1
#elif defined(__GLIBCXX__)
// if we are using gcc and Version <9 default to no filesystem
#define CLI11_HAS_FILESYSTEM 0
#else
#define CLI11_HAS_FILESYSTEM 1
#endif
#else
#define CLI11_HAS_FILESYSTEM 0
#endif
#endif
#endif
#endif

#if defined CLI11_HAS_FILESYSTEM && CLI11_HAS_FILESYSTEM > 0
#include <filesystem>  // NOLINT(build/include)
#else
#include <sys/stat.h>
#include <sys/types.h>
#endif

// Isolate symbols from other translation units that may have included their
// own copy of CLI11 by wrapping in the pxr namespace as well as a secondary
// hard-coded namespace. The latter is needed in case the outer pxr namespace
// has been disabled.
PXR_NAMESPACE_OPEN_SCOPE

namespace pxr_CLI {

namespace CLI {


/// Include the items in this namespace to get free conversion of enums to/from streams.
/// (This is available inside CLI as well, so CLI11 will use this without a using statement).
namespace enums {

/// output streaming for enumerations
template <typename T, typename = typename std::enable_if<std::is_enum<T>::value>::type>
std::ostream &operator<<(std::ostream &in, const T &item) {
    // make sure this is out of the detail namespace otherwise it won't be found when needed
    return in << static_cast<typename std::underlying_type<T>::type>(item);
}

}  // namespace enums

/// Export to CLI namespace
using enums::operator<<;

namespace detail {
/// a constant defining an expected max vector size defined to be a big number that could be multiplied by 4 and not
/// produce overflow for some expected uses
constexpr int expected_max_vector_size{1 << 29};
// Based on http://stackoverflow.com/questions/236129/split-a-string-in-c
/// Split a string by a delim
CLI11_INLINE std::vector<std::string> split(const std::string &s, char delim);

/// Simple function to join a string
template <typename T> std::string join(const T &v, std::string delim = ",") {
    std::ostringstream s;
    auto beg = std::begin(v);
    auto end = std::end(v);
    if(beg != end)
        s << *beg++;
    while(beg != end) {
        s << delim << *beg++;
    }
    return s.str();
}

/// Simple function to join a string from processed elements
template <typename T,
          typename Callable,
          typename = typename std::enable_if<!std::is_constructible<std::string, Callable>::value>::type>
std::string join(const T &v, Callable func, std::string delim = ",") {
    std::ostringstream s;
    auto beg = std::begin(v);
    auto end = std::end(v);
    auto loc = s.tellp();
    while(beg != end) {
        auto nloc = s.tellp();
        if(nloc > loc) {
            s << delim;
            loc = nloc;
        }
        s << func(*beg++);
    }
    return s.str();
}

/// Join a string in reverse order
template <typename T> std::string rjoin(const T &v, std::string delim = ",") {
    std::ostringstream s;
    for(std::size_t start = 0; start < v.size(); start++) {
        if(start > 0)
            s << delim;
        s << v[v.size() - start - 1];
    }
    return s.str();
}

// Based roughly on http://stackoverflow.com/questions/25829143/c-trim-whitespace-from-a-string

/// Trim whitespace from left of string
CLI11_INLINE std::string &ltrim(std::string &str);

/// Trim anything from left of string
CLI11_INLINE std::string &ltrim(std::string &str, const std::string &filter);

/// Trim whitespace from right of string
CLI11_INLINE std::string &rtrim(std::string &str);

/// Trim anything from right of string
CLI11_INLINE std::string &rtrim(std::string &str, const std::string &filter);

/// Trim whitespace from string
inline std::string &trim(std::string &str) { return ltrim(rtrim(str)); }

/// Trim anything from string
inline std::string &trim(std::string &str, const std::string filter) { return ltrim(rtrim(str, filter), filter); }

/// Make a copy of the string and then trim it
inline std::string trim_copy(const std::string &str) {
    std::string s = str;
    return trim(s);
}

/// remove quotes at the front and back of a string either '"' or '\''
CLI11_INLINE std::string &remove_quotes(std::string &str);

/// Add a leader to the beginning of all new lines (nothing is added
/// at the start of the first line). `"; "` would be for ini files
///
/// Can't use Regex, or this would be a subs.
CLI11_INLINE std::string fix_newlines(const std::string &leader, std::string input);

/// Make a copy of the string and then trim it, any filter string can be used (any char in string is filtered)
inline std::string trim_copy(const std::string &str, const std::string &filter) {
    std::string s = str;
    return trim(s, filter);
}
/// Print a two part "help" string
CLI11_INLINE std::ostream &
format_help(std::ostream &out, std::string name, const std::string &description, std::size_t wid);

/// Print subcommand aliases
CLI11_INLINE std::ostream &format_aliases(std::ostream &out, const std::vector<std::string> &aliases, std::size_t wid);

/// Verify the first character of an option
/// - is a trigger character, ! has special meaning and new lines would just be annoying to deal with
template <typename T> bool valid_first_char(T c) { return ((c != '-') && (c != '!') && (c != ' ') && c != '\n'); }

/// Verify following characters of an option
template <typename T> bool valid_later_char(T c) {
    // = and : are value separators, { has special meaning for option defaults,
    // and \n would just be annoying to deal with in many places allowing space here has too much potential for
    // inadvertent entry errors and bugs
    return ((c != '=') && (c != ':') && (c != '{') && (c != ' ') && c != '\n');
}

/// Verify an option/subcommand name
CLI11_INLINE bool valid_name_string(const std::string &str);

/// Verify an app name
inline bool valid_alias_name_string(const std::string &str) {
    static const std::string badChars(std::string("\n") + '\0');
    return (str.find_first_of(badChars) == std::string::npos);
}

/// check if a string is a container segment separator (empty or "%%")
inline bool is_separator(const std::string &str) {
    static const std::string sep("%%");
    return (str.empty() || str == sep);
}

/// Verify that str consists of letters only
inline bool isalpha(const std::string &str) {
    return std::all_of(str.begin(), str.end(), [](char c) { return std::isalpha(c, std::locale()); });
}

/// Return a lower case version of a string
inline std::string to_lower(std::string str) {
    std::transform(std::begin(str), std::end(str), std::begin(str), [](const std::string::value_type &x) {
        return std::tolower(x, std::locale());
    });
    return str;
}

/// remove underscores from a string
inline std::string remove_underscore(std::string str) {
    str.erase(std::remove(std::begin(str), std::end(str), '_'), std::end(str));
    return str;
}

/// Find and replace a substring with another substring
CLI11_INLINE std::string find_and_replace(std::string str, std::string from, std::string to);

/// check if the flag definitions has possible false flags
inline bool has_default_flag_values(const std::string &flags) {
    return (flags.find_first_of("{!") != std::string::npos);
}

CLI11_INLINE void remove_default_flag_values(std::string &flags);

/// Check if a string is a member of a list of strings and optionally ignore case or ignore underscores
CLI11_INLINE std::ptrdiff_t find_member(std::string name,
                                        const std::vector<std::string> names,
                                        bool ignore_case = false,
                                        bool ignore_underscore = false);

/// Find a trigger string and call a modify callable function that takes the current string and starting position of the
/// trigger and returns the position in the string to search for the next trigger string
template <typename Callable> inline std::string find_and_modify(std::string str, std::string trigger, Callable modify) {
    std::size_t start_pos = 0;
    while((start_pos = str.find(trigger, start_pos)) != std::string::npos) {
        start_pos = modify(str, start_pos);
    }
    return str;
}

/// Split a string '"one two" "three"' into 'one two', 'three'
/// Quote characters can be ` ' or "
CLI11_INLINE std::vector<std::string> split_up(std::string str, char delimiter = '\0');

/// This function detects an equal or colon followed by an escaped quote after an argument
/// then modifies the string to replace the equality with a space.  This is needed
/// to allow the split up function to work properly and is intended to be used with the find_and_modify function
/// the return value is the offset+1 which is required by the find_and_modify function.
CLI11_INLINE std::size_t escape_detect(std::string &str, std::size_t offset);

/// Add quotes if the string contains spaces
CLI11_INLINE std::string &add_quotes_if_needed(std::string &str);

}  // namespace detail




namespace detail {
CLI11_INLINE std::vector<std::string> split(const std::string &s, char delim) {
    std::vector<std::string> elems;
    // Check to see if empty string, give consistent result
    if(s.empty()) {
        elems.emplace_back();
    } else {
        std::stringstream ss;
        ss.str(s);
        std::string item;
        while(std::getline(ss, item, delim)) {
            elems.push_back(item);
        }
    }
    return elems;
}

CLI11_INLINE std::string &ltrim(std::string &str) {
    auto it = std::find_if(str.begin(), str.end(), [](char ch) { return !std::isspace<char>(ch, std::locale()); });
    str.erase(str.begin(), it);
    return str;
}

CLI11_INLINE std::string &ltrim(std::string &str, const std::string &filter) {
    auto it = std::find_if(str.begin(), str.end(), [&filter](char ch) { return filter.find(ch) == std::string::npos; });
    str.erase(str.begin(), it);
    return str;
}

CLI11_INLINE std::string &rtrim(std::string &str) {
    auto it = std::find_if(str.rbegin(), str.rend(), [](char ch) { return !std::isspace<char>(ch, std::locale()); });
    str.erase(it.base(), str.end());
    return str;
}

CLI11_INLINE std::string &rtrim(std::string &str, const std::string &filter) {
    auto it =
        std::find_if(str.rbegin(), str.rend(), [&filter](char ch) { return filter.find(ch) == std::string::npos; });
    str.erase(it.base(), str.end());
    return str;
}

CLI11_INLINE std::string &remove_quotes(std::string &str) {
    if(str.length() > 1 && (str.front() == '"' || str.front() == '\'')) {
        if(str.front() == str.back()) {
            str.pop_back();
            str.erase(str.begin(), str.begin() + 1);
        }
    }
    return str;
}

CLI11_INLINE std::string fix_newlines(const std::string &leader, std::string input) {
    std::string::size_type n = 0;
    while(n != std::string::npos && n < input.size()) {
        n = input.find('\n', n);
        if(n != std::string::npos) {
            input = input.substr(0, n + 1) + leader + input.substr(n + 1);
            n += leader.size();
        }
    }
    return input;
}

CLI11_INLINE std::ostream &
format_help(std::ostream &out, std::string name, const std::string &description, std::size_t wid) {
    name = "  " + name;
    out << std::setw(static_cast<int>(wid)) << std::left << name;
    if(!description.empty()) {
        if(name.length() >= wid)
            out << "\n" << std::setw(static_cast<int>(wid)) << "";
        for(const char c : description) {
            out.put(c);
            if(c == '\n') {
                out << std::setw(static_cast<int>(wid)) << "";
            }
        }
    }
    out << "\n";
    return out;
}

CLI11_INLINE std::ostream &format_aliases(std::ostream &out, const std::vector<std::string> &aliases, std::size_t wid) {
    if(!aliases.empty()) {
        out << std::setw(static_cast<int>(wid)) << "     aliases: ";
        bool front = true;
        for(const auto &alias : aliases) {
            if(!front) {
                out << ", ";
            } else {
                front = false;
            }
            out << detail::fix_newlines("              ", alias);
        }
        out << "\n";
    }
    return out;
}

CLI11_INLINE bool valid_name_string(const std::string &str) {
    if(str.empty() || !valid_first_char(str[0])) {
        return false;
    }
    auto e = str.end();
    for(auto c = str.begin() + 1; c != e; ++c)
        if(!valid_later_char(*c))
            return false;
    return true;
}

CLI11_INLINE std::string find_and_replace(std::string str, std::string from, std::string to) {

    std::size_t start_pos = 0;

    while((start_pos = str.find(from, start_pos)) != std::string::npos) {
        str.replace(start_pos, from.length(), to);
        start_pos += to.length();
    }

    return str;
}

CLI11_INLINE void remove_default_flag_values(std::string &flags) {
    auto loc = flags.find_first_of('{', 2);
    while(loc != std::string::npos) {
        auto finish = flags.find_first_of("},", loc + 1);
        if((finish != std::string::npos) && (flags[finish] == '}')) {
            flags.erase(flags.begin() + static_cast<std::ptrdiff_t>(loc),
                        flags.begin() + static_cast<std::ptrdiff_t>(finish) + 1);
        }
        loc = flags.find_first_of('{', loc + 1);
    }
    flags.erase(std::remove(flags.begin(), flags.end(), '!'), flags.end());
}

CLI11_INLINE std::ptrdiff_t
find_member(std::string name, const std::vector<std::string> names, bool ignore_case, bool ignore_underscore) {
    auto it = std::end(names);
    if(ignore_case) {
        if(ignore_underscore) {
            name = detail::to_lower(detail::remove_underscore(name));
            it = std::find_if(std::begin(names), std::end(names), [&name](std::string local_name) {
                return detail::to_lower(detail::remove_underscore(local_name)) == name;
            });
        } else {
            name = detail::to_lower(name);
            it = std::find_if(std::begin(names), std::end(names), [&name](std::string local_name) {
                return detail::to_lower(local_name) == name;
            });
        }

    } else if(ignore_underscore) {
        name = detail::remove_underscore(name);
        it = std::find_if(std::begin(names), std::end(names), [&name](std::string local_name) {
            return detail::remove_underscore(local_name) == name;
        });
    } else {
        it = std::find(std::begin(names), std::end(names), name);
    }

    return (it != std::end(names)) ? (it - std::begin(names)) : (-1);
}

CLI11_INLINE std::vector<std::string> split_up(std::string str, char delimiter) {

    const std::string delims("\'\"`");
    auto find_ws = [delimiter](char ch) {
        return (delimiter == '\0') ? std::isspace<char>(ch, std::locale()) : (ch == delimiter);
    };
    trim(str);

    std::vector<std::string> output;
    bool embeddedQuote = false;
    char keyChar = ' ';
    while(!str.empty()) {
        if(delims.find_first_of(str[0]) != std::string::npos) {
            keyChar = str[0];
            auto end = str.find_first_of(keyChar, 1);
            while((end != std::string::npos) && (str[end - 1] == '\\')) {  // deal with escaped quotes
                end = str.find_first_of(keyChar, end + 1);
                embeddedQuote = true;
            }
            if(end != std::string::npos) {
                output.push_back(str.substr(1, end - 1));
                if(end + 2 < str.size()) {
                    str = str.substr(end + 2);
                } else {
                    str.clear();
                }

            } else {
                output.push_back(str.substr(1));
                str = "";
            }
        } else {
            auto it = std::find_if(std::begin(str), std::end(str), find_ws);
            if(it != std::end(str)) {
                std::string value = std::string(str.begin(), it);
                output.push_back(value);
                str = std::string(it + 1, str.end());
            } else {
                output.push_back(str);
                str = "";
            }
        }
        // transform any embedded quotes into the regular character
        if(embeddedQuote) {
            output.back() = find_and_replace(output.back(), std::string("\\") + keyChar, std::string(1, keyChar));
            embeddedQuote = false;
        }
        trim(str);
    }
    return output;
}

CLI11_INLINE std::size_t escape_detect(std::string &str, std::size_t offset) {
    auto next = str[offset + 1];
    if((next == '\"') || (next == '\'') || (next == '`')) {
        auto astart = str.find_last_of("-/ \"\'`", offset - 1);
        if(astart != std::string::npos) {
            if(str[astart] == ((str[offset] == '=') ? '-' : '/'))
                str[offset] = ' ';  // interpret this as a space so the split_up works properly
        }
    }
    return offset + 1;
}

CLI11_INLINE std::string &add_quotes_if_needed(std::string &str) {
    if((str.front() != '"' && str.front() != '\'') || str.front() != str.back()) {
        char quote = str.find('"') < str.find('\'') ? '\'' : '"';
        if(str.find(' ') != std::string::npos) {
            str.insert(0, 1, quote);
            str.append(1, quote);
        }
    }
    return str;
}

}  // namespace detail



// Use one of these on all error classes.
// These are temporary and are undef'd at the end of this file.
#define CLI11_ERROR_DEF(parent, name)                                                                                  \
  protected:                                                                                                           \
    name(std::string ename, std::string msg, int exit_code) : parent(std::move(ename), std::move(msg), exit_code) {}   \
    name(std::string ename, std::string msg, ExitCodes exit_code)                                                      \
        : parent(std::move(ename), std::move(msg), exit_code) {}                                                       \
                                                                                                                       \
  public:                                                                                                              \
    name(std::string msg, ExitCodes exit_code) : parent(#name, std::move(msg), exit_code) {}                           \
    name(std::string msg, int exit_code) : parent(#name, std::move(msg), exit_code) {}

// This is added after the one above if a class is used directly and builds its own message
#define CLI11_ERROR_SIMPLE(name)                                                                                       \
    explicit name(std::string msg) : name(#name, msg, ExitCodes::name) {}

/// These codes are part of every error in CLI. They can be obtained from e using e.exit_code or as a quick shortcut,
/// int values from e.get_error_code().
enum class ExitCodes {
    Success = 0,
    IncorrectConstruction = 100,
    BadNameString,
    OptionAlreadyAdded,
    FileError,
    ConversionError,
    ValidationError,
    RequiredError,
    RequiresError,
    ExcludesError,
    ExtrasError,
    ConfigError,
    InvalidError,
    HorribleError,
    OptionNotFound,
    ArgumentMismatch,
    BaseClass = 127
};

// Error definitions

/// @defgroup error_group Errors
/// @brief Errors thrown by CLI11
///
/// These are the errors that can be thrown. Some of them, like CLI::Success, are not really errors.
/// @{

/// All errors derive from this one
class Error : public std::runtime_error {
    int actual_exit_code;
    std::string error_name{"Error"};

  public:
    CLI11_NODISCARD int get_exit_code() const { return actual_exit_code; }

    CLI11_NODISCARD std::string get_name() const { return error_name; }

    Error(std::string name, std::string msg, int exit_code = static_cast<int>(ExitCodes::BaseClass))
        : runtime_error(msg), actual_exit_code(exit_code), error_name(std::move(name)) {}

    Error(std::string name, std::string msg, ExitCodes exit_code) : Error(name, msg, static_cast<int>(exit_code)) {}
};

// Note: Using Error::Error constructors does not work on GCC 4.7

/// Construction errors (not in parsing)
class ConstructionError : public Error {
    CLI11_ERROR_DEF(Error, ConstructionError)
};

/// Thrown when an option is set to conflicting values (non-vector and multi args, for example)
class IncorrectConstruction : public ConstructionError {
    CLI11_ERROR_DEF(ConstructionError, IncorrectConstruction)
    CLI11_ERROR_SIMPLE(IncorrectConstruction)
    static IncorrectConstruction PositionalFlag(std::string name) {
        return IncorrectConstruction(name + ": Flags cannot be positional");
    }
    static IncorrectConstruction Set0Opt(std::string name) {
        return IncorrectConstruction(name + ": Cannot set 0 expected, use a flag instead");
    }
    static IncorrectConstruction SetFlag(std::string name) {
        return IncorrectConstruction(name + ": Cannot set an expected number for flags");
    }
    static IncorrectConstruction ChangeNotVector(std::string name) {
        return IncorrectConstruction(name + ": You can only change the expected arguments for vectors");
    }
    static IncorrectConstruction AfterMultiOpt(std::string name) {
        return IncorrectConstruction(
            name + ": You can't change expected arguments after you've changed the multi option policy!");
    }
    static IncorrectConstruction MissingOption(std::string name) {
        return IncorrectConstruction("Option " + name + " is not defined");
    }
    static IncorrectConstruction MultiOptionPolicy(std::string name) {
        return IncorrectConstruction(name + ": multi_option_policy only works for flags and exact value options");
    }
};

/// Thrown on construction of a bad name
class BadNameString : public ConstructionError {
    CLI11_ERROR_DEF(ConstructionError, BadNameString)
    CLI11_ERROR_SIMPLE(BadNameString)
    static BadNameString OneCharName(std::string name) { return BadNameString("Invalid one char name: " + name); }
    static BadNameString BadLongName(std::string name) { return BadNameString("Bad long name: " + name); }
    static BadNameString DashesOnly(std::string name) {
        return BadNameString("Must have a name, not just dashes: " + name);
    }
    static BadNameString MultiPositionalNames(std::string name) {
        return BadNameString("Only one positional name allowed, remove: " + name);
    }
};

/// Thrown when an option already exists
class OptionAlreadyAdded : public ConstructionError {
    CLI11_ERROR_DEF(ConstructionError, OptionAlreadyAdded)
    explicit OptionAlreadyAdded(std::string name)
        : OptionAlreadyAdded(name + " is already added", ExitCodes::OptionAlreadyAdded) {}
    static OptionAlreadyAdded Requires(std::string name, std::string other) {
        return {name + " requires " + other, ExitCodes::OptionAlreadyAdded};
    }
    static OptionAlreadyAdded Excludes(std::string name, std::string other) {
        return {name + " excludes " + other, ExitCodes::OptionAlreadyAdded};
    }
};

// Parsing errors

/// Anything that can error in Parse
class ParseError : public Error {
    CLI11_ERROR_DEF(Error, ParseError)
};

// Not really "errors"

/// This is a successful completion on parsing, supposed to exit
class Success : public ParseError {
    CLI11_ERROR_DEF(ParseError, Success)
    Success() : Success("Successfully completed, should be caught and quit", ExitCodes::Success) {}
};

/// -h or --help on command line
class CallForHelp : public Success {
    CLI11_ERROR_DEF(Success, CallForHelp)
    CallForHelp() : CallForHelp("This should be caught in your main function, see examples", ExitCodes::Success) {}
};

/// Usually something like --help-all on command line
class CallForAllHelp : public Success {
    CLI11_ERROR_DEF(Success, CallForAllHelp)
    CallForAllHelp()
        : CallForAllHelp("This should be caught in your main function, see examples", ExitCodes::Success) {}
};

/// -v or --version on command line
class CallForVersion : public Success {
    CLI11_ERROR_DEF(Success, CallForVersion)
    CallForVersion()
        : CallForVersion("This should be caught in your main function, see examples", ExitCodes::Success) {}
};

/// Does not output a diagnostic in CLI11_PARSE, but allows main() to return with a specific error code.
class RuntimeError : public ParseError {
    CLI11_ERROR_DEF(ParseError, RuntimeError)
    explicit RuntimeError(int exit_code = 1) : RuntimeError("Runtime error", exit_code) {}
};

/// Thrown when parsing an INI file and it is missing
class FileError : public ParseError {
    CLI11_ERROR_DEF(ParseError, FileError)
    CLI11_ERROR_SIMPLE(FileError)
    static FileError Missing(std::string name) { return FileError(name + " was not readable (missing?)"); }
};

/// Thrown when conversion call back fails, such as when an int fails to coerce to a string
class ConversionError : public ParseError {
    CLI11_ERROR_DEF(ParseError, ConversionError)
    CLI11_ERROR_SIMPLE(ConversionError)
    ConversionError(std::string member, std::string name)
        : ConversionError("The value " + member + " is not an allowed value for " + name) {}
    ConversionError(std::string name, std::vector<std::string> results)
        : ConversionError("Could not convert: " + name + " = " + detail::join(results)) {}
    static ConversionError TooManyInputsFlag(std::string name) {
        return ConversionError(name + ": too many inputs for a flag");
    }
    static ConversionError TrueFalse(std::string name) {
        return ConversionError(name + ": Should be true/false or a number");
    }
};

/// Thrown when validation of results fails
class ValidationError : public ParseError {
    CLI11_ERROR_DEF(ParseError, ValidationError)
    CLI11_ERROR_SIMPLE(ValidationError)
    explicit ValidationError(std::string name, std::string msg) : ValidationError(name + ": " + msg) {}
};

/// Thrown when a required option is missing
class RequiredError : public ParseError {
    CLI11_ERROR_DEF(ParseError, RequiredError)
    explicit RequiredError(std::string name) : RequiredError(name + " is required", ExitCodes::RequiredError) {}
    static RequiredError Subcommand(std::size_t min_subcom) {
        if(min_subcom == 1) {
            return RequiredError("A subcommand");
        }
        return {"Requires at least " + std::to_string(min_subcom) + " subcommands", ExitCodes::RequiredError};
    }
    static RequiredError
    Option(std::size_t min_option, std::size_t max_option, std::size_t used, const std::string &option_list) {
        if((min_option == 1) && (max_option == 1) && (used == 0))
            return RequiredError("Exactly 1 option from [" + option_list + "]");
        if((min_option == 1) && (max_option == 1) && (used > 1)) {
            return {"Exactly 1 option from [" + option_list + "] is required and " + std::to_string(used) +
                        " were given",
                    ExitCodes::RequiredError};
        }
        if((min_option == 1) && (used == 0))
            return RequiredError("At least 1 option from [" + option_list + "]");
        if(used < min_option) {
            return {"Requires at least " + std::to_string(min_option) + " options used and only " +
                        std::to_string(used) + "were given from [" + option_list + "]",
                    ExitCodes::RequiredError};
        }
        if(max_option == 1)
            return {"Requires at most 1 options be given from [" + option_list + "]", ExitCodes::RequiredError};

        return {"Requires at most " + std::to_string(max_option) + " options be used and " + std::to_string(used) +
                    "were given from [" + option_list + "]",
                ExitCodes::RequiredError};
    }
};

/// Thrown when the wrong number of arguments has been received
class ArgumentMismatch : public ParseError {
    CLI11_ERROR_DEF(ParseError, ArgumentMismatch)
    CLI11_ERROR_SIMPLE(ArgumentMismatch)
    ArgumentMismatch(std::string name, int expected, std::size_t received)
        : ArgumentMismatch(expected > 0 ? ("Expected exactly " + std::to_string(expected) + " arguments to " + name +
                                           ", got " + std::to_string(received))
                                        : ("Expected at least " + std::to_string(-expected) + " arguments to " + name +
                                           ", got " + std::to_string(received)),
                           ExitCodes::ArgumentMismatch) {}

    static ArgumentMismatch AtLeast(std::string name, int num, std::size_t received) {
        return ArgumentMismatch(name + ": At least " + std::to_string(num) + " required but received " +
                                std::to_string(received));
    }
    static ArgumentMismatch AtMost(std::string name, int num, std::size_t received) {
        return ArgumentMismatch(name + ": At Most " + std::to_string(num) + " required but received " +
                                std::to_string(received));
    }
    static ArgumentMismatch TypedAtLeast(std::string name, int num, std::string type) {
        return ArgumentMismatch(name + ": " + std::to_string(num) + " required " + type + " missing");
    }
    static ArgumentMismatch FlagOverride(std::string name) {
        return ArgumentMismatch(name + " was given a disallowed flag override");
    }
    static ArgumentMismatch PartialType(std::string name, int num, std::string type) {
        return ArgumentMismatch(name + ": " + type + " only partially specified: " + std::to_string(num) +
                                " required for each element");
    }
};

/// Thrown when a requires option is missing
class RequiresError : public ParseError {
    CLI11_ERROR_DEF(ParseError, RequiresError)
    RequiresError(std::string curname, std::string subname)
        : RequiresError(curname + " requires " + subname, ExitCodes::RequiresError) {}
};

/// Thrown when an excludes option is present
class ExcludesError : public ParseError {
    CLI11_ERROR_DEF(ParseError, ExcludesError)
    ExcludesError(std::string curname, std::string subname)
        : ExcludesError(curname + " excludes " + subname, ExitCodes::ExcludesError) {}
};

/// Thrown when too many positionals or options are found
class ExtrasError : public ParseError {
    CLI11_ERROR_DEF(ParseError, ExtrasError)
    explicit ExtrasError(std::vector<std::string> args)
        : ExtrasError((args.size() > 1 ? "The following arguments were not expected: "
                                       : "The following argument was not expected: ") +
                          detail::rjoin(args, " "),
                      ExitCodes::ExtrasError) {}
    ExtrasError(const std::string &name, std::vector<std::string> args)
        : ExtrasError(name,
                      (args.size() > 1 ? "The following arguments were not expected: "
                                       : "The following argument was not expected: ") +
                          detail::rjoin(args, " "),
                      ExitCodes::ExtrasError) {}
};

/// Thrown when extra values are found in an INI file
class ConfigError : public ParseError {
    CLI11_ERROR_DEF(ParseError, ConfigError)
    CLI11_ERROR_SIMPLE(ConfigError)
    static ConfigError Extras(std::string item) { return ConfigError("INI was not able to parse " + item); }
    static ConfigError NotConfigurable(std::string item) {
        return ConfigError(item + ": This option is not allowed in a configuration file");
    }
};

/// Thrown when validation fails before parsing
class InvalidError : public ParseError {
    CLI11_ERROR_DEF(ParseError, InvalidError)
    explicit InvalidError(std::string name)
        : InvalidError(name + ": Too many positional arguments with unlimited expected args", ExitCodes::InvalidError) {
    }
};

/// This is just a safety check to verify selection and parsing match - you should not ever see it
/// Strings are directly added to this error, but again, it should never be seen.
class HorribleError : public ParseError {
    CLI11_ERROR_DEF(ParseError, HorribleError)
    CLI11_ERROR_SIMPLE(HorribleError)
};

// After parsing

/// Thrown when counting a non-existent option
class OptionNotFound : public Error {
    CLI11_ERROR_DEF(Error, OptionNotFound)
    explicit OptionNotFound(std::string name) : OptionNotFound(name + " not found", ExitCodes::OptionNotFound) {}
};

#undef CLI11_ERROR_DEF
#undef CLI11_ERROR_SIMPLE

/// @}




// Type tools

// Utilities for type enabling
namespace detail {
// Based generally on https://rmf.io/cxx11/almost-static-if
/// Simple empty scoped class
enum class enabler {};

/// An instance to use in EnableIf
constexpr enabler dummy = {};
}  // namespace detail

/// A copy of enable_if_t from C++14, compatible with C++11.
///
/// We could check to see if C++14 is being used, but it does not hurt to redefine this
/// (even Google does this: https://github.com/google/skia/blob/main/include/private/SkTLogic.h)
/// It is not in the std namespace anyway, so no harm done.
template <bool B, class T = void> using enable_if_t = typename std::enable_if<B, T>::type;

/// A copy of std::void_t from C++17 (helper for C++11 and C++14)
template <typename... Ts> struct make_void { using type = void; };

/// A copy of std::void_t from C++17 - same reasoning as enable_if_t, it does not hurt to redefine
template <typename... Ts> using void_t = typename make_void<Ts...>::type;

/// A copy of std::conditional_t from C++14 - same reasoning as enable_if_t, it does not hurt to redefine
template <bool B, class T, class F> using conditional_t = typename std::conditional<B, T, F>::type;

/// Check to see if something is bool (fail check by default)
template <typename T> struct is_bool : std::false_type {};

/// Check to see if something is bool (true if actually a bool)
template <> struct is_bool<bool> : std::true_type {};

/// Check to see if something is a shared pointer
template <typename T> struct is_shared_ptr : std::false_type {};

/// Check to see if something is a shared pointer (True if really a shared pointer)
template <typename T> struct is_shared_ptr<std::shared_ptr<T>> : std::true_type {};

/// Check to see if something is a shared pointer (True if really a shared pointer)
template <typename T> struct is_shared_ptr<const std::shared_ptr<T>> : std::true_type {};

/// Check to see if something is copyable pointer
template <typename T> struct is_copyable_ptr {
    static bool const value = is_shared_ptr<T>::value || std::is_pointer<T>::value;
};

/// This can be specialized to override the type deduction for IsMember.
template <typename T> struct IsMemberType { using type = T; };

/// The main custom type needed here is const char * should be a string.
template <> struct IsMemberType<const char *> { using type = std::string; };

namespace detail {

// These are utilities for IsMember and other transforming objects

/// Handy helper to access the element_type generically. This is not part of is_copyable_ptr because it requires that
/// pointer_traits<T> be valid.

/// not a pointer
template <typename T, typename Enable = void> struct element_type { using type = T; };

template <typename T> struct element_type<T, typename std::enable_if<is_copyable_ptr<T>::value>::type> {
    using type = typename std::pointer_traits<T>::element_type;
};

/// Combination of the element type and value type - remove pointer (including smart pointers) and get the value_type of
/// the container
template <typename T> struct element_value_type { using type = typename element_type<T>::type::value_type; };

/// Adaptor for set-like structure: This just wraps a normal container in a few utilities that do almost nothing.
template <typename T, typename _ = void> struct pair_adaptor : std::false_type {
    using value_type = typename T::value_type;
    using first_type = typename std::remove_const<value_type>::type;
    using second_type = typename std::remove_const<value_type>::type;

    /// Get the first value (really just the underlying value)
    template <typename Q> static auto first(Q &&pair_value) -> decltype(std::forward<Q>(pair_value)) {
        return std::forward<Q>(pair_value);
    }
    /// Get the second value (really just the underlying value)
    template <typename Q> static auto second(Q &&pair_value) -> decltype(std::forward<Q>(pair_value)) {
        return std::forward<Q>(pair_value);
    }
};

/// Adaptor for map-like structure (true version, must have key_type and mapped_type).
/// This wraps a mapped container in a few utilities access it in a general way.
template <typename T>
struct pair_adaptor<
    T,
    conditional_t<false, void_t<typename T::value_type::first_type, typename T::value_type::second_type>, void>>
    : std::true_type {
    using value_type = typename T::value_type;
    using first_type = typename std::remove_const<typename value_type::first_type>::type;
    using second_type = typename std::remove_const<typename value_type::second_type>::type;

    /// Get the first value (really just the underlying value)
    template <typename Q> static auto first(Q &&pair_value) -> decltype(std::get<0>(std::forward<Q>(pair_value))) {
        return std::get<0>(std::forward<Q>(pair_value));
    }
    /// Get the second value (really just the underlying value)
    template <typename Q> static auto second(Q &&pair_value) -> decltype(std::get<1>(std::forward<Q>(pair_value))) {
        return std::get<1>(std::forward<Q>(pair_value));
    }
};

// Warning is suppressed due to "bug" in gcc<5.0 and gcc 7.0 with c++17 enabled that generates a Wnarrowing warning
// in the unevaluated context even if the function that was using this wasn't used.  The standard says narrowing in
// brace initialization shouldn't be allowed but for backwards compatibility gcc allows it in some contexts.  It is a
// little fuzzy what happens in template constructs and I think that was something GCC took a little while to work out.
// But regardless some versions of gcc generate a warning when they shouldn't from the following code so that should be
// suppressed
#ifdef __GNUC__
#pragma GCC diagnostic push
#pragma GCC diagnostic ignored "-Wnarrowing"
#endif
// check for constructibility from a specific type and copy assignable used in the parse detection
template <typename T, typename C> class is_direct_constructible {
    template <typename TT, typename CC>
    static auto test(int, std::true_type) -> decltype(
// NVCC warns about narrowing conversions here
#ifdef __CUDACC__
#pragma diag_suppress 2361
#endif
        TT{std::declval<CC>()}
#ifdef __CUDACC__
#pragma diag_default 2361
#endif
        ,
        std::is_move_assignable<TT>());

    template <typename TT, typename CC> static auto test(int, std::false_type) -> std::false_type;

    template <typename, typename> static auto test(...) -> std::false_type;

  public:
    static constexpr bool value = decltype(test<T, C>(0, typename std::is_constructible<T, C>::type()))::value;
};
#ifdef __GNUC__
#pragma GCC diagnostic pop
#endif

// Check for output streamability
// Based on https://stackoverflow.com/questions/22758291/how-can-i-detect-if-a-type-can-be-streamed-to-an-stdostream

template <typename T, typename S = std::ostringstream> class is_ostreamable {
    template <typename TT, typename SS>
    static auto test(int) -> decltype(std::declval<SS &>() << std::declval<TT>(), std::true_type());

    template <typename, typename> static auto test(...) -> std::false_type;

  public:
    static constexpr bool value = decltype(test<T, S>(0))::value;
};

/// Check for input streamability
template <typename T, typename S = std::istringstream> class is_istreamable {
    template <typename TT, typename SS>
    static auto test(int) -> decltype(std::declval<SS &>() >> std::declval<TT &>(), std::true_type());

    template <typename, typename> static auto test(...) -> std::false_type;

  public:
    static constexpr bool value = decltype(test<T, S>(0))::value;
};

/// Check for complex
template <typename T> class is_complex {
    template <typename TT>
    static auto test(int) -> decltype(std::declval<TT>().real(), std::declval<TT>().imag(), std::true_type());

    template <typename> static auto test(...) -> std::false_type;

  public:
    static constexpr bool value = decltype(test<T>(0))::value;
};

/// Templated operation to get a value from a stream
template <typename T, enable_if_t<is_istreamable<T>::value, detail::enabler> = detail::dummy>
bool from_stream(const std::string &istring, T &obj) {
    std::istringstream is;
    is.str(istring);
    is >> obj;
    return !is.fail() && !is.rdbuf()->in_avail();
}

template <typename T, enable_if_t<!is_istreamable<T>::value, detail::enabler> = detail::dummy>
bool from_stream(const std::string & /*istring*/, T & /*obj*/) {
    return false;
}

// check to see if an object is a mutable container (fail by default)
template <typename T, typename _ = void> struct is_mutable_container : std::false_type {};

/// type trait to test if a type is a mutable container meaning it has a value_type, it has an iterator, a clear, and
/// end methods and an insert function.  And for our purposes we exclude std::string and types that can be constructed
/// from a std::string
template <typename T>
struct is_mutable_container<
    T,
    conditional_t<false,
                  void_t<typename T::value_type,
                         decltype(std::declval<T>().end()),
                         decltype(std::declval<T>().clear()),
                         decltype(std::declval<T>().insert(std::declval<decltype(std::declval<T>().end())>(),
                                                           std::declval<const typename T::value_type &>()))>,
                  void>>
    : public conditional_t<std::is_constructible<T, std::string>::value, std::false_type, std::true_type> {};

// check to see if an object is a mutable container (fail by default)
template <typename T, typename _ = void> struct is_readable_container : std::false_type {};

/// type trait to test if a type is a container meaning it has a value_type, it has an iterator, a clear, and an end
/// methods and an insert function.  And for our purposes we exclude std::string and types that can be constructed from
/// a std::string
template <typename T>
struct is_readable_container<
    T,
    conditional_t<false, void_t<decltype(std::declval<T>().end()), decltype(std::declval<T>().begin())>, void>>
    : public std::true_type {};

// check to see if an object is a wrapper (fail by default)
template <typename T, typename _ = void> struct is_wrapper : std::false_type {};

// check if an object is a wrapper (it has a value_type defined)
template <typename T>
struct is_wrapper<T, conditional_t<false, void_t<typename T::value_type>, void>> : public std::true_type {};

// Check for tuple like types, as in classes with a tuple_size type trait
template <typename S> class is_tuple_like {
    template <typename SS>
    // static auto test(int)
    //     -> decltype(std::conditional<(std::tuple_size<SS>::value > 0), std::true_type, std::false_type>::type());
    static auto test(int) -> decltype(std::tuple_size<typename std::decay<SS>::type>::value, std::true_type{});
    template <typename> static auto test(...) -> std::false_type;

  public:
    static constexpr bool value = decltype(test<S>(0))::value;
};

/// Convert an object to a string (directly forward if this can become a string)
template <typename T, enable_if_t<std::is_convertible<T, std::string>::value, detail::enabler> = detail::dummy>
auto to_string(T &&value) -> decltype(std::forward<T>(value)) {
    return std::forward<T>(value);
}

/// Construct a string from the object
template <typename T,
          enable_if_t<std::is_constructible<std::string, T>::value && !std::is_convertible<T, std::string>::value,
                      detail::enabler> = detail::dummy>
std::string to_string(const T &value) {
    return std::string(value);  // NOLINT(google-readability-casting)
}

/// Convert an object to a string (streaming must be supported for that type)
template <typename T,
          enable_if_t<!std::is_convertible<std::string, T>::value && !std::is_constructible<std::string, T>::value &&
                          is_ostreamable<T>::value,
                      detail::enabler> = detail::dummy>
std::string to_string(T &&value) {
    std::stringstream stream;
    stream << value;
    return stream.str();
}

/// If conversion is not supported, return an empty string (streaming is not supported for that type)
template <typename T,
          enable_if_t<!std::is_constructible<std::string, T>::value && !is_ostreamable<T>::value &&
                          !is_readable_container<typename std::remove_const<T>::type>::value,
                      detail::enabler> = detail::dummy>
std::string to_string(T &&) {
    return {};
}

/// convert a readable container to a string
template <typename T,
          enable_if_t<!std::is_constructible<std::string, T>::value && !is_ostreamable<T>::value &&
                          is_readable_container<T>::value,
                      detail::enabler> = detail::dummy>
std::string to_string(T &&variable) {
    auto cval = variable.begin();
    auto end = variable.end();
    if(cval == end) {
        return {"{}"};
    }
    std::vector<std::string> defaults;
    while(cval != end) {
        defaults.emplace_back(CLI::detail::to_string(*cval));
        ++cval;
    }
    return {"[" + detail::join(defaults) + "]"};
}

/// special template overload
template <typename T1,
          typename T2,
          typename T,
          enable_if_t<std::is_same<T1, T2>::value, detail::enabler> = detail::dummy>
auto checked_to_string(T &&value) -> decltype(to_string(std::forward<T>(value))) {
    return to_string(std::forward<T>(value));
}

/// special template overload
template <typename T1,
          typename T2,
          typename T,
          enable_if_t<!std::is_same<T1, T2>::value, detail::enabler> = detail::dummy>
std::string checked_to_string(T &&) {
    return std::string{};
}
/// get a string as a convertible value for arithmetic types
template <typename T, enable_if_t<std::is_arithmetic<T>::value, detail::enabler> = detail::dummy>
std::string value_string(const T &value) {
    return std::to_string(value);
}
/// get a string as a convertible value for enumerations
template <typename T, enable_if_t<std::is_enum<T>::value, detail::enabler> = detail::dummy>
std::string value_string(const T &value) {
    return std::to_string(static_cast<typename std::underlying_type<T>::type>(value));
}
/// for other types just use the regular to_string function
template <typename T,
          enable_if_t<!std::is_enum<T>::value && !std::is_arithmetic<T>::value, detail::enabler> = detail::dummy>
auto value_string(const T &value) -> decltype(to_string(value)) {
    return to_string(value);
}

/// template to get the underlying value type if it exists or use a default
template <typename T, typename def, typename Enable = void> struct wrapped_type { using type = def; };

/// Type size for regular object types that do not look like a tuple
template <typename T, typename def> struct wrapped_type<T, def, typename std::enable_if<is_wrapper<T>::value>::type> {
    using type = typename T::value_type;
};

/// This will only trigger for actual void type
template <typename T, typename Enable = void> struct type_count_base { static const int value{0}; };

/// Type size for regular object types that do not look like a tuple
template <typename T>
struct type_count_base<T,
                       typename std::enable_if<!is_tuple_like<T>::value && !is_mutable_container<T>::value &&
                                               !std::is_void<T>::value>::type> {
    static constexpr int value{1};
};

/// the base tuple size
template <typename T>
struct type_count_base<T, typename std::enable_if<is_tuple_like<T>::value && !is_mutable_container<T>::value>::type> {
    static constexpr int value{std::tuple_size<T>::value};
};

/// Type count base for containers is the type_count_base of the individual element
template <typename T> struct type_count_base<T, typename std::enable_if<is_mutable_container<T>::value>::type> {
    static constexpr int value{type_count_base<typename T::value_type>::value};
};

/// Set of overloads to get the type size of an object

/// forward declare the subtype_count structure
template <typename T> struct subtype_count;

/// forward declare the subtype_count_min structure
template <typename T> struct subtype_count_min;

/// This will only trigger for actual void type
template <typename T, typename Enable = void> struct type_count { static const int value{0}; };

/// Type size for regular object types that do not look like a tuple
template <typename T>
struct type_count<T,
                  typename std::enable_if<!is_wrapper<T>::value && !is_tuple_like<T>::value && !is_complex<T>::value &&
                                          !std::is_void<T>::value>::type> {
    static constexpr int value{1};
};

/// Type size for complex since it sometimes looks like a wrapper
template <typename T> struct type_count<T, typename std::enable_if<is_complex<T>::value>::type> {
    static constexpr int value{2};
};

/// Type size of types that are wrappers,except complex and tuples(which can also be wrappers sometimes)
template <typename T> struct type_count<T, typename std::enable_if<is_mutable_container<T>::value>::type> {
    static constexpr int value{subtype_count<typename T::value_type>::value};
};

/// Type size of types that are wrappers,except containers complex and tuples(which can also be wrappers sometimes)
template <typename T>
struct type_count<T,
                  typename std::enable_if<is_wrapper<T>::value && !is_complex<T>::value && !is_tuple_like<T>::value &&
                                          !is_mutable_container<T>::value>::type> {
    static constexpr int value{type_count<typename T::value_type>::value};
};

/// 0 if the index > tuple size
template <typename T, std::size_t I>
constexpr typename std::enable_if<I == type_count_base<T>::value, int>::type tuple_type_size() {
    return 0;
}

/// Recursively generate the tuple type name
template <typename T, std::size_t I>
    constexpr typename std::enable_if < I<type_count_base<T>::value, int>::type tuple_type_size() {
    return subtype_count<typename std::tuple_element<I, T>::type>::value + tuple_type_size<T, I + 1>();
}

/// Get the type size of the sum of type sizes for all the individual tuple types
template <typename T> struct type_count<T, typename std::enable_if<is_tuple_like<T>::value>::type> {
    static constexpr int value{tuple_type_size<T, 0>()};
};

/// definition of subtype count
template <typename T> struct subtype_count {
    static constexpr int value{is_mutable_container<T>::value ? expected_max_vector_size : type_count<T>::value};
};

/// This will only trigger for actual void type
template <typename T, typename Enable = void> struct type_count_min { static const int value{0}; };

/// Type size for regular object types that do not look like a tuple
template <typename T>
struct type_count_min<
    T,
    typename std::enable_if<!is_mutable_container<T>::value && !is_tuple_like<T>::value && !is_wrapper<T>::value &&
                            !is_complex<T>::value && !std::is_void<T>::value>::type> {
    static constexpr int value{type_count<T>::value};
};

/// Type size for complex since it sometimes looks like a wrapper
template <typename T> struct type_count_min<T, typename std::enable_if<is_complex<T>::value>::type> {
    static constexpr int value{1};
};

/// Type size min of types that are wrappers,except complex and tuples(which can also be wrappers sometimes)
template <typename T>
struct type_count_min<
    T,
    typename std::enable_if<is_wrapper<T>::value && !is_complex<T>::value && !is_tuple_like<T>::value>::type> {
    static constexpr int value{subtype_count_min<typename T::value_type>::value};
};

/// 0 if the index > tuple size
template <typename T, std::size_t I>
constexpr typename std::enable_if<I == type_count_base<T>::value, int>::type tuple_type_size_min() {
    return 0;
}

/// Recursively generate the tuple type name
template <typename T, std::size_t I>
    constexpr typename std::enable_if < I<type_count_base<T>::value, int>::type tuple_type_size_min() {
    return subtype_count_min<typename std::tuple_element<I, T>::type>::value + tuple_type_size_min<T, I + 1>();
}

/// Get the type size of the sum of type sizes for all the individual tuple types
template <typename T> struct type_count_min<T, typename std::enable_if<is_tuple_like<T>::value>::type> {
    static constexpr int value{tuple_type_size_min<T, 0>()};
};

/// definition of subtype count
template <typename T> struct subtype_count_min {
    static constexpr int value{is_mutable_container<T>::value
                                   ? ((type_count<T>::value < expected_max_vector_size) ? type_count<T>::value : 0)
                                   : type_count_min<T>::value};
};

/// This will only trigger for actual void type
template <typename T, typename Enable = void> struct expected_count { static const int value{0}; };

/// For most types the number of expected items is 1
template <typename T>
struct expected_count<T,
                      typename std::enable_if<!is_mutable_container<T>::value && !is_wrapper<T>::value &&
                                              !std::is_void<T>::value>::type> {
    static constexpr int value{1};
};
/// number of expected items in a vector
template <typename T> struct expected_count<T, typename std::enable_if<is_mutable_container<T>::value>::type> {
    static constexpr int value{expected_max_vector_size};
};

/// number of expected items in a vector
template <typename T>
struct expected_count<T, typename std::enable_if<!is_mutable_container<T>::value && is_wrapper<T>::value>::type> {
    static constexpr int value{expected_count<typename T::value_type>::value};
};

// Enumeration of the different supported categorizations of objects
enum class object_category : int {
    char_value = 1,
    integral_value = 2,
    unsigned_integral = 4,
    enumeration = 6,
    boolean_value = 8,
    floating_point = 10,
    number_constructible = 12,
    double_constructible = 14,
    integer_constructible = 16,
    // string like types
    string_assignable = 23,
    string_constructible = 24,
    other = 45,
    // special wrapper or container types
    wrapper_value = 50,
    complex_number = 60,
    tuple_value = 70,
    container_value = 80,

};

/// Set of overloads to classify an object according to type

/// some type that is not otherwise recognized
template <typename T, typename Enable = void> struct classify_object {
    static constexpr object_category value{object_category::other};
};

/// Signed integers
template <typename T>
struct classify_object<
    T,
    typename std::enable_if<std::is_integral<T>::value && !std::is_same<T, char>::value && std::is_signed<T>::value &&
                            !is_bool<T>::value && !std::is_enum<T>::value>::type> {
    static constexpr object_category value{object_category::integral_value};
};

/// Unsigned integers
template <typename T>
struct classify_object<T,
                       typename std::enable_if<std::is_integral<T>::value && std::is_unsigned<T>::value &&
                                               !std::is_same<T, char>::value && !is_bool<T>::value>::type> {
    static constexpr object_category value{object_category::unsigned_integral};
};

/// single character values
template <typename T>
struct classify_object<T, typename std::enable_if<std::is_same<T, char>::value && !std::is_enum<T>::value>::type> {
    static constexpr object_category value{object_category::char_value};
};

/// Boolean values
template <typename T> struct classify_object<T, typename std::enable_if<is_bool<T>::value>::type> {
    static constexpr object_category value{object_category::boolean_value};
};

/// Floats
template <typename T> struct classify_object<T, typename std::enable_if<std::is_floating_point<T>::value>::type> {
    static constexpr object_category value{object_category::floating_point};
};

/// String and similar direct assignment
template <typename T>
struct classify_object<T,
                       typename std::enable_if<!std::is_floating_point<T>::value && !std::is_integral<T>::value &&
                                               std::is_assignable<T &, std::string>::value>::type> {
    static constexpr object_category value{object_category::string_assignable};
};

/// String and similar constructible and copy assignment
template <typename T>
struct classify_object<
    T,
    typename std::enable_if<!std::is_floating_point<T>::value && !std::is_integral<T>::value &&
                            !std::is_assignable<T &, std::string>::value && (type_count<T>::value == 1) &&
                            std::is_constructible<T, std::string>::value>::type> {
    static constexpr object_category value{object_category::string_constructible};
};

/// Enumerations
template <typename T> struct classify_object<T, typename std::enable_if<std::is_enum<T>::value>::type> {
    static constexpr object_category value{object_category::enumeration};
};

template <typename T> struct classify_object<T, typename std::enable_if<is_complex<T>::value>::type> {
    static constexpr object_category value{object_category::complex_number};
};

/// Handy helper to contain a bunch of checks that rule out many common types (integers, string like, floating point,
/// vectors, and enumerations
template <typename T> struct uncommon_type {
    using type = typename std::conditional<!std::is_floating_point<T>::value && !std::is_integral<T>::value &&
                                               !std::is_assignable<T &, std::string>::value &&
                                               !std::is_constructible<T, std::string>::value && !is_complex<T>::value &&
                                               !is_mutable_container<T>::value && !std::is_enum<T>::value,
                                           std::true_type,
                                           std::false_type>::type;
    static constexpr bool value = type::value;
};

/// wrapper type
template <typename T>
struct classify_object<T,
                       typename std::enable_if<(!is_mutable_container<T>::value && is_wrapper<T>::value &&
                                                !is_tuple_like<T>::value && uncommon_type<T>::value)>::type> {
    static constexpr object_category value{object_category::wrapper_value};
};

/// Assignable from double or int
template <typename T>
struct classify_object<T,
                       typename std::enable_if<uncommon_type<T>::value && type_count<T>::value == 1 &&
                                               !is_wrapper<T>::value && is_direct_constructible<T, double>::value &&
                                               is_direct_constructible<T, int>::value>::type> {
    static constexpr object_category value{object_category::number_constructible};
};

/// Assignable from int
template <typename T>
struct classify_object<T,
                       typename std::enable_if<uncommon_type<T>::value && type_count<T>::value == 1 &&
                                               !is_wrapper<T>::value && !is_direct_constructible<T, double>::value &&
                                               is_direct_constructible<T, int>::value>::type> {
    static constexpr object_category value{object_category::integer_constructible};
};

/// Assignable from double
template <typename T>
struct classify_object<T,
                       typename std::enable_if<uncommon_type<T>::value && type_count<T>::value == 1 &&
                                               !is_wrapper<T>::value && is_direct_constructible<T, double>::value &&
                                               !is_direct_constructible<T, int>::value>::type> {
    static constexpr object_category value{object_category::double_constructible};
};

/// Tuple type
template <typename T>
struct classify_object<
    T,
    typename std::enable_if<is_tuple_like<T>::value &&
                            ((type_count<T>::value >= 2 && !is_wrapper<T>::value) ||
                             (uncommon_type<T>::value && !is_direct_constructible<T, double>::value &&
                              !is_direct_constructible<T, int>::value) ||
                             (uncommon_type<T>::value && type_count<T>::value >= 2))>::type> {
    static constexpr object_category value{object_category::tuple_value};
    // the condition on this class requires it be like a tuple, but on some compilers (like Xcode) tuples can be
    // constructed from just the first element so tuples of <string, int,int> can be constructed from a string, which
    // could lead to issues so there are two variants of the condition, the first isolates things with a type size >=2
    // mainly to get tuples on Xcode with the exception of wrappers, the second is the main one and just separating out
    // those cases that are caught by other object classifications
};

/// container type
template <typename T> struct classify_object<T, typename std::enable_if<is_mutable_container<T>::value>::type> {
    static constexpr object_category value{object_category::container_value};
};

// Type name print

/// Was going to be based on
///  http://stackoverflow.com/questions/1055452/c-get-name-of-type-in-template
/// But this is cleaner and works better in this case

template <typename T,
          enable_if_t<classify_object<T>::value == object_category::char_value, detail::enabler> = detail::dummy>
constexpr const char *type_name() {
    return "CHAR";
}

template <typename T,
          enable_if_t<classify_object<T>::value == object_category::integral_value ||
                          classify_object<T>::value == object_category::integer_constructible,
                      detail::enabler> = detail::dummy>
constexpr const char *type_name() {
    return "INT";
}

template <typename T,
          enable_if_t<classify_object<T>::value == object_category::unsigned_integral, detail::enabler> = detail::dummy>
constexpr const char *type_name() {
    return "UINT";
}

template <typename T,
          enable_if_t<classify_object<T>::value == object_category::floating_point ||
                          classify_object<T>::value == object_category::number_constructible ||
                          classify_object<T>::value == object_category::double_constructible,
                      detail::enabler> = detail::dummy>
constexpr const char *type_name() {
    return "FLOAT";
}

/// Print name for enumeration types
template <typename T,
          enable_if_t<classify_object<T>::value == object_category::enumeration, detail::enabler> = detail::dummy>
constexpr const char *type_name() {
    return "ENUM";
}

/// Print name for enumeration types
template <typename T,
          enable_if_t<classify_object<T>::value == object_category::boolean_value, detail::enabler> = detail::dummy>
constexpr const char *type_name() {
    return "BOOLEAN";
}

/// Print name for enumeration types
template <typename T,
          enable_if_t<classify_object<T>::value == object_category::complex_number, detail::enabler> = detail::dummy>
constexpr const char *type_name() {
    return "COMPLEX";
}

/// Print for all other types
template <typename T,
          enable_if_t<classify_object<T>::value >= object_category::string_assignable &&
                          classify_object<T>::value <= object_category::other,
                      detail::enabler> = detail::dummy>
constexpr const char *type_name() {
    return "TEXT";
}
/// typename for tuple value
template <typename T,
          enable_if_t<classify_object<T>::value == object_category::tuple_value && type_count_base<T>::value >= 2,
                      detail::enabler> = detail::dummy>
std::string type_name();  // forward declaration

/// Generate type name for a wrapper or container value
template <typename T,
          enable_if_t<classify_object<T>::value == object_category::container_value ||
                          classify_object<T>::value == object_category::wrapper_value,
                      detail::enabler> = detail::dummy>
std::string type_name();  // forward declaration

/// Print name for single element tuple types
template <typename T,
          enable_if_t<classify_object<T>::value == object_category::tuple_value && type_count_base<T>::value == 1,
                      detail::enabler> = detail::dummy>
inline std::string type_name() {
    return type_name<typename std::decay<typename std::tuple_element<0, T>::type>::type>();
}

/// Empty string if the index > tuple size
template <typename T, std::size_t I>
inline typename std::enable_if<I == type_count_base<T>::value, std::string>::type tuple_name() {
    return std::string{};
}

/// Recursively generate the tuple type name
template <typename T, std::size_t I>
inline typename std::enable_if<(I < type_count_base<T>::value), std::string>::type tuple_name() {
    auto str = std::string{type_name<typename std::decay<typename std::tuple_element<I, T>::type>::type>()} + ',' +
               tuple_name<T, I + 1>();
    if(str.back() == ',')
        str.pop_back();
    return str;
}

/// Print type name for tuples with 2 or more elements
template <typename T,
          enable_if_t<classify_object<T>::value == object_category::tuple_value && type_count_base<T>::value >= 2,
                      detail::enabler>>
inline std::string type_name() {
    auto tname = std::string(1, '[') + tuple_name<T, 0>();
    tname.push_back(']');
    return tname;
}

/// get the type name for a type that has a value_type member
template <typename T,
          enable_if_t<classify_object<T>::value == object_category::container_value ||
                          classify_object<T>::value == object_category::wrapper_value,
                      detail::enabler>>
inline std::string type_name() {
    return type_name<typename T::value_type>();
}

// Lexical cast

/// Convert to an unsigned integral
template <typename T, enable_if_t<std::is_unsigned<T>::value, detail::enabler> = detail::dummy>
bool integral_conversion(const std::string &input, T &output) noexcept {
    if(input.empty()) {
        return false;
    }
    char *val = nullptr;
    std::uint64_t output_ll = std::strtoull(input.c_str(), &val, 0);
    output = static_cast<T>(output_ll);
    if(val == (input.c_str() + input.size()) && static_cast<std::uint64_t>(output) == output_ll) {
        return true;
    }
    val = nullptr;
    std::int64_t output_sll = std::strtoll(input.c_str(), &val, 0);
    if(val == (input.c_str() + input.size())) {
        output = (output_sll < 0) ? static_cast<T>(0) : static_cast<T>(output_sll);
        return (static_cast<std::int64_t>(output) == output_sll);
    }
    return false;
}

/// Convert to a signed integral
template <typename T, enable_if_t<std::is_signed<T>::value, detail::enabler> = detail::dummy>
bool integral_conversion(const std::string &input, T &output) noexcept {
    if(input.empty()) {
        return false;
    }
    char *val = nullptr;
    std::int64_t output_ll = std::strtoll(input.c_str(), &val, 0);
    output = static_cast<T>(output_ll);
    if(val == (input.c_str() + input.size()) && static_cast<std::int64_t>(output) == output_ll) {
        return true;
    }
    if(input == "true") {
        // this is to deal with a few oddities with flags and wrapper int types
        output = static_cast<T>(1);
        return true;
    }
    return false;
}

/// Convert a flag into an integer value  typically binary flags
inline std::int64_t to_flag_value(std::string val) {
    static const std::string trueString("true");
    static const std::string falseString("false");
    if(val == trueString) {
        return 1;
    }
    if(val == falseString) {
        return -1;
    }
    val = detail::to_lower(val);
    std::int64_t ret = 0;
    if(val.size() == 1) {
        if(val[0] >= '1' && val[0] <= '9') {
            return (static_cast<std::int64_t>(val[0]) - '0');
        }
        switch(val[0]) {
        case '0':
        case 'f':
        case 'n':
        case '-':
            ret = -1;
            break;
        case 't':
        case 'y':
        case '+':
            ret = 1;
            break;
        default:
            throw std::invalid_argument("unrecognized character");
        }
        return ret;
    }
    if(val == trueString || val == "on" || val == "yes" || val == "enable") {
        ret = 1;
    } else if(val == falseString || val == "off" || val == "no" || val == "disable") {
        ret = -1;
    } else {
        ret = std::stoll(val);
    }
    return ret;
}

/// Integer conversion
template <typename T,
          enable_if_t<classify_object<T>::value == object_category::integral_value ||
                          classify_object<T>::value == object_category::unsigned_integral,
                      detail::enabler> = detail::dummy>
bool lexical_cast(const std::string &input, T &output) {
    return integral_conversion(input, output);
}

/// char values
template <typename T,
          enable_if_t<classify_object<T>::value == object_category::char_value, detail::enabler> = detail::dummy>
bool lexical_cast(const std::string &input, T &output) {
    if(input.size() == 1) {
        output = static_cast<T>(input[0]);
        return true;
    }
    return integral_conversion(input, output);
}

/// Boolean values
template <typename T,
          enable_if_t<classify_object<T>::value == object_category::boolean_value, detail::enabler> = detail::dummy>
bool lexical_cast(const std::string &input, T &output) {
    try {
        auto out = to_flag_value(input);
        output = (out > 0);
        return true;
    } catch(const std::invalid_argument &) {
        return false;
    } catch(const std::out_of_range &) {
        // if the number is out of the range of a 64 bit value then it is still a number and for this purpose is still
        // valid all we care about the sign
        output = (input[0] != '-');
        return true;
    }
}

/// Floats
template <typename T,
          enable_if_t<classify_object<T>::value == object_category::floating_point, detail::enabler> = detail::dummy>
bool lexical_cast(const std::string &input, T &output) {
    if(input.empty()) {
        return false;
    }
    char *val = nullptr;
    auto output_ld = std::strtold(input.c_str(), &val);
    output = static_cast<T>(output_ld);
    return val == (input.c_str() + input.size());
}

/// complex
template <typename T,
          enable_if_t<classify_object<T>::value == object_category::complex_number, detail::enabler> = detail::dummy>
bool lexical_cast(const std::string &input, T &output) {
    using XC = typename wrapped_type<T, double>::type;
    XC x{0.0}, y{0.0};
    auto str1 = input;
    bool worked = false;
    auto nloc = str1.find_last_of("+-");
    if(nloc != std::string::npos && nloc > 0) {
        worked = detail::lexical_cast(str1.substr(0, nloc), x);
        str1 = str1.substr(nloc);
        if(str1.back() == 'i' || str1.back() == 'j')
            str1.pop_back();
        worked = worked && detail::lexical_cast(str1, y);
    } else {
        if(str1.back() == 'i' || str1.back() == 'j') {
            str1.pop_back();
            worked = detail::lexical_cast(str1, y);
            x = XC{0};
        } else {
            worked = detail::lexical_cast(str1, x);
            y = XC{0};
        }
    }
    if(worked) {
        output = T{x, y};
        return worked;
    }
    return from_stream(input, output);
}

/// String and similar direct assignment
template <typename T,
          enable_if_t<classify_object<T>::value == object_category::string_assignable, detail::enabler> = detail::dummy>
bool lexical_cast(const std::string &input, T &output) {
    output = input;
    return true;
}

/// String and similar constructible and copy assignment
template <
    typename T,
    enable_if_t<classify_object<T>::value == object_category::string_constructible, detail::enabler> = detail::dummy>
bool lexical_cast(const std::string &input, T &output) {
    output = T(input);
    return true;
}

/// Enumerations
template <typename T,
          enable_if_t<classify_object<T>::value == object_category::enumeration, detail::enabler> = detail::dummy>
bool lexical_cast(const std::string &input, T &output) {
    typename std::underlying_type<T>::type val;
    if(!integral_conversion(input, val)) {
        return false;
    }
    output = static_cast<T>(val);
    return true;
}

/// wrapper types
template <typename T,
          enable_if_t<classify_object<T>::value == object_category::wrapper_value &&
                          std::is_assignable<T &, typename T::value_type>::value,
                      detail::enabler> = detail::dummy>
bool lexical_cast(const std::string &input, T &output) {
    typename T::value_type val;
    if(lexical_cast(input, val)) {
        output = val;
        return true;
    }
    return from_stream(input, output);
}

template <typename T,
          enable_if_t<classify_object<T>::value == object_category::wrapper_value &&
                          !std::is_assignable<T &, typename T::value_type>::value && std::is_assignable<T &, T>::value,
                      detail::enabler> = detail::dummy>
bool lexical_cast(const std::string &input, T &output) {
    typename T::value_type val;
    if(lexical_cast(input, val)) {
        output = T{val};
        return true;
    }
    return from_stream(input, output);
}

/// Assignable from double or int
template <
    typename T,
    enable_if_t<classify_object<T>::value == object_category::number_constructible, detail::enabler> = detail::dummy>
bool lexical_cast(const std::string &input, T &output) {
    int val = 0;
    if(integral_conversion(input, val)) {
        output = T(val);
        return true;
    }

    double dval = 0.0;
    if(lexical_cast(input, dval)) {
        output = T{dval};
        return true;
    }

    return from_stream(input, output);
}

/// Assignable from int
template <
    typename T,
    enable_if_t<classify_object<T>::value == object_category::integer_constructible, detail::enabler> = detail::dummy>
bool lexical_cast(const std::string &input, T &output) {
    int val = 0;
    if(integral_conversion(input, val)) {
        output = T(val);
        return true;
    }
    return from_stream(input, output);
}

/// Assignable from double
template <
    typename T,
    enable_if_t<classify_object<T>::value == object_category::double_constructible, detail::enabler> = detail::dummy>
bool lexical_cast(const std::string &input, T &output) {
    double val = 0.0;
    if(lexical_cast(input, val)) {
        output = T{val};
        return true;
    }
    return from_stream(input, output);
}

/// Non-string convertible from an int
template <typename T,
          enable_if_t<classify_object<T>::value == object_category::other && std::is_assignable<T &, int>::value,
                      detail::enabler> = detail::dummy>
bool lexical_cast(const std::string &input, T &output) {
    int val = 0;
    if(integral_conversion(input, val)) {
#ifdef _MSC_VER
#pragma warning(push)
#pragma warning(disable : 4800)
#endif
        // with Atomic<XX> this could produce a warning due to the conversion but if atomic gets here it is an old style
        // so will most likely still work
        output = val;
#ifdef _MSC_VER
#pragma warning(pop)
#endif
        return true;
    }
    // LCOV_EXCL_START
    // This version of cast is only used for odd cases in an older compilers the fail over
    // from_stream is tested elsewhere an not relevant for coverage here
    return from_stream(input, output);
    // LCOV_EXCL_STOP
}

/// Non-string parsable by a stream
template <typename T,
          enable_if_t<classify_object<T>::value == object_category::other && !std::is_assignable<T &, int>::value,
                      detail::enabler> = detail::dummy>
bool lexical_cast(const std::string &input, T &output) {
    static_assert(is_istreamable<T>::value,
                  "option object type must have a lexical cast overload or streaming input operator(>>) defined, if it "
                  "is convertible from another type use the add_option<T, XC>(...) with XC being the known type");
    return from_stream(input, output);
}

/// Assign a value through lexical cast operations
/// Strings can be empty so we need to do a little different
template <typename AssignTo,
          typename ConvertTo,
          enable_if_t<std::is_same<AssignTo, ConvertTo>::value &&
                          (classify_object<AssignTo>::value == object_category::string_assignable ||
                           classify_object<AssignTo>::value == object_category::string_constructible),
                      detail::enabler> = detail::dummy>
bool lexical_assign(const std::string &input, AssignTo &output) {
    return lexical_cast(input, output);
}

/// Assign a value through lexical cast operations
template <typename AssignTo,
          typename ConvertTo,
          enable_if_t<std::is_same<AssignTo, ConvertTo>::value && std::is_assignable<AssignTo &, AssignTo>::value &&
                          classify_object<AssignTo>::value != object_category::string_assignable &&
                          classify_object<AssignTo>::value != object_category::string_constructible,
                      detail::enabler> = detail::dummy>
bool lexical_assign(const std::string &input, AssignTo &output) {
    if(input.empty()) {
        output = AssignTo{};
        return true;
    }

    return lexical_cast(input, output);
}

/// Assign a value through lexical cast operations
template <typename AssignTo,
          typename ConvertTo,
          enable_if_t<std::is_same<AssignTo, ConvertTo>::value && !std::is_assignable<AssignTo &, AssignTo>::value &&
                          classify_object<AssignTo>::value == object_category::wrapper_value,
                      detail::enabler> = detail::dummy>
bool lexical_assign(const std::string &input, AssignTo &output) {
    if(input.empty()) {
        typename AssignTo::value_type emptyVal{};
        output = emptyVal;
        return true;
    }
    return lexical_cast(input, output);
}

/// Assign a value through lexical cast operations for int compatible values
/// mainly for atomic operations on some compilers
template <typename AssignTo,
          typename ConvertTo,
          enable_if_t<std::is_same<AssignTo, ConvertTo>::value && !std::is_assignable<AssignTo &, AssignTo>::value &&
                          classify_object<AssignTo>::value != object_category::wrapper_value &&
                          std::is_assignable<AssignTo &, int>::value,
                      detail::enabler> = detail::dummy>
bool lexical_assign(const std::string &input, AssignTo &output) {
    if(input.empty()) {
        output = 0;
        return true;
    }
    int val = 0;
    if(lexical_cast(input, val)) {
        output = val;
        return true;
    }
    return false;
}

/// Assign a value converted from a string in lexical cast to the output value directly
template <typename AssignTo,
          typename ConvertTo,
          enable_if_t<!std::is_same<AssignTo, ConvertTo>::value && std::is_assignable<AssignTo &, ConvertTo &>::value,
                      detail::enabler> = detail::dummy>
bool lexical_assign(const std::string &input, AssignTo &output) {
    ConvertTo val{};
    bool parse_result = (!input.empty()) ? lexical_cast<ConvertTo>(input, val) : true;
    if(parse_result) {
        output = val;
    }
    return parse_result;
}

/// Assign a value from a lexical cast through constructing a value and move assigning it
template <
    typename AssignTo,
    typename ConvertTo,
    enable_if_t<!std::is_same<AssignTo, ConvertTo>::value && !std::is_assignable<AssignTo &, ConvertTo &>::value &&
                    std::is_move_assignable<AssignTo>::value,
                detail::enabler> = detail::dummy>
bool lexical_assign(const std::string &input, AssignTo &output) {
    ConvertTo val{};
    bool parse_result = input.empty() ? true : lexical_cast<ConvertTo>(input, val);
    if(parse_result) {
        output = AssignTo(val);  // use () form of constructor to allow some implicit conversions
    }
    return parse_result;
}

/// primary lexical conversion operation, 1 string to 1 type of some kind
template <typename AssignTo,
          typename ConvertTo,
          enable_if_t<classify_object<ConvertTo>::value <= object_category::other &&
                          classify_object<AssignTo>::value <= object_category::wrapper_value,
                      detail::enabler> = detail::dummy>
bool lexical_conversion(const std::vector<std ::string> &strings, AssignTo &output) {
    return lexical_assign<AssignTo, ConvertTo>(strings[0], output);
}

/// Lexical conversion if there is only one element but the conversion type is for two, then call a two element
/// constructor
template <typename AssignTo,
          typename ConvertTo,
          enable_if_t<(type_count<AssignTo>::value <= 2) && expected_count<AssignTo>::value == 1 &&
                          is_tuple_like<ConvertTo>::value && type_count_base<ConvertTo>::value == 2,
                      detail::enabler> = detail::dummy>
bool lexical_conversion(const std::vector<std ::string> &strings, AssignTo &output) {
    // the remove const is to handle pair types coming from a container
    typename std::remove_const<typename std::tuple_element<0, ConvertTo>::type>::type v1;
    typename std::tuple_element<1, ConvertTo>::type v2;
    bool retval = lexical_assign<decltype(v1), decltype(v1)>(strings[0], v1);
    if(strings.size() > 1) {
        retval = retval && lexical_assign<decltype(v2), decltype(v2)>(strings[1], v2);
    }
    if(retval) {
        output = AssignTo{v1, v2};
    }
    return retval;
}

/// Lexical conversion of a container types of single elements
template <class AssignTo,
          class ConvertTo,
          enable_if_t<is_mutable_container<AssignTo>::value && is_mutable_container<ConvertTo>::value &&
                          type_count<ConvertTo>::value == 1,
                      detail::enabler> = detail::dummy>
bool lexical_conversion(const std::vector<std ::string> &strings, AssignTo &output) {
    output.erase(output.begin(), output.end());
    if(strings.size() == 1 && strings[0] == "{}") {
        return true;
    }
    bool skip_remaining = false;
    if(strings.size() == 2 && strings[0] == "{}" && is_separator(strings[1])) {
        skip_remaining = true;
    }
    for(const auto &elem : strings) {
        typename AssignTo::value_type out;
        bool retval = lexical_assign<typename AssignTo::value_type, typename ConvertTo::value_type>(elem, out);
        if(!retval) {
            return false;
        }
        output.insert(output.end(), std::move(out));
        if(skip_remaining) {
            break;
        }
    }
    return (!output.empty());
}

/// Lexical conversion for complex types
template <class AssignTo, class ConvertTo, enable_if_t<is_complex<ConvertTo>::value, detail::enabler> = detail::dummy>
bool lexical_conversion(const std::vector<std::string> &strings, AssignTo &output) {

    if(strings.size() >= 2 && !strings[1].empty()) {
        using XC2 = typename wrapped_type<ConvertTo, double>::type;
        XC2 x{0.0}, y{0.0};
        auto str1 = strings[1];
        if(str1.back() == 'i' || str1.back() == 'j') {
            str1.pop_back();
        }
        auto worked = detail::lexical_cast(strings[0], x) && detail::lexical_cast(str1, y);
        if(worked) {
            output = ConvertTo{x, y};
        }
        return worked;
    }
    return lexical_assign<AssignTo, ConvertTo>(strings[0], output);
}

/// Conversion to a vector type using a particular single type as the conversion type
template <class AssignTo,
          class ConvertTo,
          enable_if_t<is_mutable_container<AssignTo>::value && (expected_count<ConvertTo>::value == 1) &&
                          (type_count<ConvertTo>::value == 1),
                      detail::enabler> = detail::dummy>
bool lexical_conversion(const std::vector<std ::string> &strings, AssignTo &output) {
    bool retval = true;
    output.clear();
    output.reserve(strings.size());
    for(const auto &elem : strings) {

        output.emplace_back();
        retval = retval && lexical_assign<typename AssignTo::value_type, ConvertTo>(elem, output.back());
    }
    return (!output.empty()) && retval;
}

// forward declaration

/// Lexical conversion of a container types with conversion type of two elements
template <class AssignTo,
          class ConvertTo,
          enable_if_t<is_mutable_container<AssignTo>::value && is_mutable_container<ConvertTo>::value &&
                          type_count_base<ConvertTo>::value == 2,
                      detail::enabler> = detail::dummy>
bool lexical_conversion(std::vector<std::string> strings, AssignTo &output);

/// Lexical conversion of a vector types with type_size >2 forward declaration
template <class AssignTo,
          class ConvertTo,
          enable_if_t<is_mutable_container<AssignTo>::value && is_mutable_container<ConvertTo>::value &&
                          type_count_base<ConvertTo>::value != 2 &&
                          ((type_count<ConvertTo>::value > 2) ||
                           (type_count<ConvertTo>::value > type_count_base<ConvertTo>::value)),
                      detail::enabler> = detail::dummy>
bool lexical_conversion(const std::vector<std::string> &strings, AssignTo &output);

/// Conversion for tuples
template <class AssignTo,
          class ConvertTo,
          enable_if_t<is_tuple_like<AssignTo>::value && is_tuple_like<ConvertTo>::value &&
                          (type_count_base<ConvertTo>::value != type_count<ConvertTo>::value ||
                           type_count<ConvertTo>::value > 2),
                      detail::enabler> = detail::dummy>
bool lexical_conversion(const std::vector<std::string> &strings, AssignTo &output);  // forward declaration

/// Conversion for operations where the assigned type is some class but the conversion is a mutable container or large
/// tuple
template <typename AssignTo,
          typename ConvertTo,
          enable_if_t<!is_tuple_like<AssignTo>::value && !is_mutable_container<AssignTo>::value &&
                          classify_object<ConvertTo>::value != object_category::wrapper_value &&
                          (is_mutable_container<ConvertTo>::value || type_count<ConvertTo>::value > 2),
                      detail::enabler> = detail::dummy>
bool lexical_conversion(const std::vector<std ::string> &strings, AssignTo &output) {

    if(strings.size() > 1 || (!strings.empty() && !(strings.front().empty()))) {
        ConvertTo val;
        auto retval = lexical_conversion<ConvertTo, ConvertTo>(strings, val);
        output = AssignTo{val};
        return retval;
    }
    output = AssignTo{};
    return true;
}

/// function template for converting tuples if the static Index is greater than the tuple size
template <class AssignTo, class ConvertTo, std::size_t I>
inline typename std::enable_if<(I >= type_count_base<AssignTo>::value), bool>::type
tuple_conversion(const std::vector<std::string> &, AssignTo &) {
    return true;
}

/// Conversion of a tuple element where the type size ==1 and not a mutable container
template <class AssignTo, class ConvertTo>
inline typename std::enable_if<!is_mutable_container<ConvertTo>::value && type_count<ConvertTo>::value == 1, bool>::type
tuple_type_conversion(std::vector<std::string> &strings, AssignTo &output) {
    auto retval = lexical_assign<AssignTo, ConvertTo>(strings[0], output);
    strings.erase(strings.begin());
    return retval;
}

/// Conversion of a tuple element where the type size !=1 but the size is fixed and not a mutable container
template <class AssignTo, class ConvertTo>
inline typename std::enable_if<!is_mutable_container<ConvertTo>::value && (type_count<ConvertTo>::value > 1) &&
                                   type_count<ConvertTo>::value == type_count_min<ConvertTo>::value,
                               bool>::type
tuple_type_conversion(std::vector<std::string> &strings, AssignTo &output) {
    auto retval = lexical_conversion<AssignTo, ConvertTo>(strings, output);
    strings.erase(strings.begin(), strings.begin() + type_count<ConvertTo>::value);
    return retval;
}

/// Conversion of a tuple element where the type is a mutable container or a type with different min and max type sizes
template <class AssignTo, class ConvertTo>
inline typename std::enable_if<is_mutable_container<ConvertTo>::value ||
                                   type_count<ConvertTo>::value != type_count_min<ConvertTo>::value,
                               bool>::type
tuple_type_conversion(std::vector<std::string> &strings, AssignTo &output) {

    std::size_t index{subtype_count_min<ConvertTo>::value};
    const std::size_t mx_count{subtype_count<ConvertTo>::value};
    const std::size_t mx{(std::max)(mx_count, strings.size())};

    while(index < mx) {
        if(is_separator(strings[index])) {
            break;
        }
        ++index;
    }
    bool retval = lexical_conversion<AssignTo, ConvertTo>(
        std::vector<std::string>(strings.begin(), strings.begin() + static_cast<std::ptrdiff_t>(index)), output);
    strings.erase(strings.begin(), strings.begin() + static_cast<std::ptrdiff_t>(index) + 1);
    return retval;
}

/// Tuple conversion operation
template <class AssignTo, class ConvertTo, std::size_t I>
inline typename std::enable_if<(I < type_count_base<AssignTo>::value), bool>::type
tuple_conversion(std::vector<std::string> strings, AssignTo &output) {
    bool retval = true;
    using ConvertToElement = typename std::
        conditional<is_tuple_like<ConvertTo>::value, typename std::tuple_element<I, ConvertTo>::type, ConvertTo>::type;
    if(!strings.empty()) {
        retval = retval && tuple_type_conversion<typename std::tuple_element<I, AssignTo>::type, ConvertToElement>(
                               strings, std::get<I>(output));
    }
    retval = retval && tuple_conversion<AssignTo, ConvertTo, I + 1>(std::move(strings), output);
    return retval;
}

/// Lexical conversion of a container types with tuple elements of size 2
template <class AssignTo,
          class ConvertTo,
          enable_if_t<is_mutable_container<AssignTo>::value && is_mutable_container<ConvertTo>::value &&
                          type_count_base<ConvertTo>::value == 2,
                      detail::enabler>>
bool lexical_conversion(std::vector<std::string> strings, AssignTo &output) {
    output.clear();
    while(!strings.empty()) {

        typename std::remove_const<typename std::tuple_element<0, typename ConvertTo::value_type>::type>::type v1;
        typename std::tuple_element<1, typename ConvertTo::value_type>::type v2;
        bool retval = tuple_type_conversion<decltype(v1), decltype(v1)>(strings, v1);
        if(!strings.empty()) {
            retval = retval && tuple_type_conversion<decltype(v2), decltype(v2)>(strings, v2);
        }
        if(retval) {
            output.insert(output.end(), typename AssignTo::value_type{v1, v2});
        } else {
            return false;
        }
    }
    return (!output.empty());
}

/// lexical conversion of tuples with type count>2 or tuples of types of some element with a type size>=2
template <class AssignTo,
          class ConvertTo,
          enable_if_t<is_tuple_like<AssignTo>::value && is_tuple_like<ConvertTo>::value &&
                          (type_count_base<ConvertTo>::value != type_count<ConvertTo>::value ||
                           type_count<ConvertTo>::value > 2),
                      detail::enabler>>
bool lexical_conversion(const std::vector<std ::string> &strings, AssignTo &output) {
    static_assert(
        !is_tuple_like<ConvertTo>::value || type_count_base<AssignTo>::value == type_count_base<ConvertTo>::value,
        "if the conversion type is defined as a tuple it must be the same size as the type you are converting to");
    return tuple_conversion<AssignTo, ConvertTo, 0>(strings, output);
}

/// Lexical conversion of a vector types for everything but tuples of two elements and types of size 1
template <class AssignTo,
          class ConvertTo,
          enable_if_t<is_mutable_container<AssignTo>::value && is_mutable_container<ConvertTo>::value &&
                          type_count_base<ConvertTo>::value != 2 &&
                          ((type_count<ConvertTo>::value > 2) ||
                           (type_count<ConvertTo>::value > type_count_base<ConvertTo>::value)),
                      detail::enabler>>
bool lexical_conversion(const std::vector<std ::string> &strings, AssignTo &output) {
    bool retval = true;
    output.clear();
    std::vector<std::string> temp;
    std::size_t ii{0};
    std::size_t icount{0};
    std::size_t xcm{type_count<ConvertTo>::value};
    auto ii_max = strings.size();
    while(ii < ii_max) {
        temp.push_back(strings[ii]);
        ++ii;
        ++icount;
        if(icount == xcm || is_separator(temp.back()) || ii == ii_max) {
            if(static_cast<int>(xcm) > type_count_min<ConvertTo>::value && is_separator(temp.back())) {
                temp.pop_back();
            }
            typename AssignTo::value_type temp_out;
            retval = retval &&
                     lexical_conversion<typename AssignTo::value_type, typename ConvertTo::value_type>(temp, temp_out);
            temp.clear();
            if(!retval) {
                return false;
            }
            output.insert(output.end(), std::move(temp_out));
            icount = 0;
        }
    }
    return retval;
}

/// conversion for wrapper types
template <typename AssignTo,
          class ConvertTo,
          enable_if_t<classify_object<ConvertTo>::value == object_category::wrapper_value &&
                          std::is_assignable<ConvertTo &, ConvertTo>::value,
                      detail::enabler> = detail::dummy>
bool lexical_conversion(const std::vector<std::string> &strings, AssignTo &output) {
    if(strings.empty() || strings.front().empty()) {
        output = ConvertTo{};
        return true;
    }
    typename ConvertTo::value_type val;
    if(lexical_conversion<typename ConvertTo::value_type, typename ConvertTo::value_type>(strings, val)) {
        output = ConvertTo{val};
        return true;
    }
    return false;
}

/// conversion for wrapper types
template <typename AssignTo,
          class ConvertTo,
          enable_if_t<classify_object<ConvertTo>::value == object_category::wrapper_value &&
                          !std::is_assignable<AssignTo &, ConvertTo>::value,
                      detail::enabler> = detail::dummy>
bool lexical_conversion(const std::vector<std::string> &strings, AssignTo &output) {
    using ConvertType = typename ConvertTo::value_type;
    if(strings.empty() || strings.front().empty()) {
        output = ConvertType{};
        return true;
    }
    ConvertType val;
    if(lexical_conversion<typename ConvertTo::value_type, typename ConvertTo::value_type>(strings, val)) {
        output = val;
        return true;
    }
    return false;
}

/// Sum a vector of strings
inline std::string sum_string_vector(const std::vector<std::string> &values) {
    double val{0.0};
    bool fail{false};
    std::string output;
    for(const auto &arg : values) {
        double tv{0.0};
        auto comp = detail::lexical_cast<double>(arg, tv);
        if(!comp) {
            try {
                tv = static_cast<double>(detail::to_flag_value(arg));
            } catch(const std::exception &) {
                fail = true;
                break;
            }
        }
        val += tv;
    }
    if(fail) {
        for(const auto &arg : values) {
            output.append(arg);
        }
    } else {
        if(val <= static_cast<double>((std::numeric_limits<std::int64_t>::min)()) ||
           val >= static_cast<double>((std::numeric_limits<std::int64_t>::max)()) ||
           // NOLINTNEXTLINE(clang-diagnostic-float-equal,bugprone-narrowing-conversions)
           val == static_cast<std::int64_t>(val)) {
            output = detail::value_string(static_cast<int64_t>(val));
        } else {
            output = detail::value_string(val);
        }
    }
    return output;
}

}  // namespace detail



namespace detail {

// Returns false if not a short option. Otherwise, sets opt name and rest and returns true
CLI11_INLINE bool split_short(const std::string &current, std::string &name, std::string &rest);

// Returns false if not a long option. Otherwise, sets opt name and other side of = and returns true
CLI11_INLINE bool split_long(const std::string &current, std::string &name, std::string &value);

// Returns false if not a windows style option. Otherwise, sets opt name and value and returns true
CLI11_INLINE bool split_windows_style(const std::string &current, std::string &name, std::string &value);

// Splits a string into multiple long and short names
CLI11_INLINE std::vector<std::string> split_names(std::string current);

/// extract default flag values either {def} or starting with a !
CLI11_INLINE std::vector<std::pair<std::string, std::string>> get_default_flag_values(const std::string &str);

/// Get a vector of short names, one of long names, and a single name
CLI11_INLINE std::tuple<std::vector<std::string>, std::vector<std::string>, std::string>
get_names(const std::vector<std::string> &input);

}  // namespace detail



namespace detail {

CLI11_INLINE bool split_short(const std::string &current, std::string &name, std::string &rest) {
    if(current.size() > 1 && current[0] == '-' && valid_first_char(current[1])) {
        name = current.substr(1, 1);
        rest = current.substr(2);
        return true;
    }
    return false;
}

CLI11_INLINE bool split_long(const std::string &current, std::string &name, std::string &value) {
    if(current.size() > 2 && current.substr(0, 2) == "--" && valid_first_char(current[2])) {
        auto loc = current.find_first_of('=');
        if(loc != std::string::npos) {
            name = current.substr(2, loc - 2);
            value = current.substr(loc + 1);
        } else {
            name = current.substr(2);
            value = "";
        }
        return true;
    }
    return false;
}

CLI11_INLINE bool split_windows_style(const std::string &current, std::string &name, std::string &value) {
    if(current.size() > 1 && current[0] == '/' && valid_first_char(current[1])) {
        auto loc = current.find_first_of(':');
        if(loc != std::string::npos) {
            name = current.substr(1, loc - 1);
            value = current.substr(loc + 1);
        } else {
            name = current.substr(1);
            value = "";
        }
        return true;
    }
    return false;
}

CLI11_INLINE std::vector<std::string> split_names(std::string current) {
    std::vector<std::string> output;
    std::size_t val = 0;
    while((val = current.find(',')) != std::string::npos) {
        output.push_back(trim_copy(current.substr(0, val)));
        current = current.substr(val + 1);
    }
    output.push_back(trim_copy(current));
    return output;
}

CLI11_INLINE std::vector<std::pair<std::string, std::string>> get_default_flag_values(const std::string &str) {
    std::vector<std::string> flags = split_names(str);
    flags.erase(std::remove_if(flags.begin(),
                               flags.end(),
                               [](const std::string &name) {
                                   return ((name.empty()) || (!(((name.find_first_of('{') != std::string::npos) &&
                                                                 (name.back() == '}')) ||
                                                                (name[0] == '!'))));
                               }),
                flags.end());
    std::vector<std::pair<std::string, std::string>> output;
    output.reserve(flags.size());
    for(auto &flag : flags) {
        auto def_start = flag.find_first_of('{');
        std::string defval = "false";
        if((def_start != std::string::npos) && (flag.back() == '}')) {
            defval = flag.substr(def_start + 1);
            defval.pop_back();
            flag.erase(def_start, std::string::npos);  // NOLINT(readability-suspicious-call-argument)
        }
        flag.erase(0, flag.find_first_not_of("-!"));
        output.emplace_back(flag, defval);
    }
    return output;
}

CLI11_INLINE std::tuple<std::vector<std::string>, std::vector<std::string>, std::string>
get_names(const std::vector<std::string> &input) {

    std::vector<std::string> short_names;
    std::vector<std::string> long_names;
    std::string pos_name;

    for(std::string name : input) {
        if(name.length() == 0) {
            continue;
        }
        if(name.length() > 1 && name[0] == '-' && name[1] != '-') {
            if(name.length() == 2 && valid_first_char(name[1]))
                short_names.emplace_back(1, name[1]);
            else
                throw BadNameString::OneCharName(name);
        } else if(name.length() > 2 && name.substr(0, 2) == "--") {
            name = name.substr(2);
            if(valid_name_string(name))
                long_names.push_back(name);
            else
                throw BadNameString::BadLongName(name);
        } else if(name == "-" || name == "--") {
            throw BadNameString::DashesOnly(name);
        } else {
            if(pos_name.length() > 0)
                throw BadNameString::MultiPositionalNames(name);
            pos_name = name;
        }
    }

    return std::make_tuple(short_names, long_names, pos_name);
}

}  // namespace detail



class App;

/// Holds values to load into Options
struct ConfigItem {
    /// This is the list of parents
    std::vector<std::string> parents{};

    /// This is the name
    std::string name{};

    /// Listing of inputs
    std::vector<std::string> inputs{};

    /// The list of parents and name joined by "."
    CLI11_NODISCARD std::string fullname() const {
        std::vector<std::string> tmp = parents;
        tmp.emplace_back(name);
        return detail::join(tmp, ".");
    }
};

/// This class provides a converter for configuration files.
class Config {
  protected:
    std::vector<ConfigItem> items{};

  public:
    /// Convert an app into a configuration
    virtual std::string to_config(const App *, bool, bool, std::string) const = 0;

    /// Convert a configuration into an app
    virtual std::vector<ConfigItem> from_config(std::istream &) const = 0;

    /// Get a flag value
    CLI11_NODISCARD virtual std::string to_flag(const ConfigItem &item) const {
        if(item.inputs.size() == 1) {
            return item.inputs.at(0);
        }
        if(item.inputs.empty()) {
            return "{}";
        }
        throw ConversionError::TooManyInputsFlag(item.fullname());  // LCOV_EXCL_LINE
    }

    /// Parse a config file, throw an error (ParseError:ConfigParseError or FileError) on failure
    CLI11_NODISCARD std::vector<ConfigItem> from_file(const std::string &name) const {
        std::ifstream input{name};
        if(!input.good())
            throw FileError::Missing(name);

        return from_config(input);
    }

    /// Virtual destructor
    virtual ~Config() = default;
};

/// This converter works with INI/TOML files; to write INI files use ConfigINI
class ConfigBase : public Config {
  protected:
    /// the character used for comments
    char commentChar = '#';
    /// the character used to start an array '\0' is a default to not use
    char arrayStart = '[';
    /// the character used to end an array '\0' is a default to not use
    char arrayEnd = ']';
    /// the character used to separate elements in an array
    char arraySeparator = ',';
    /// the character used separate the name from the value
    char valueDelimiter = '=';
    /// the character to use around strings
    char stringQuote = '"';
    /// the character to use around single characters
    char characterQuote = '\'';
    /// the maximum number of layers to allow
    uint8_t maximumLayers{255};
    /// the separator used to separator parent layers
    char parentSeparatorChar{'.'};
    /// Specify the configuration index to use for arrayed sections
    int16_t configIndex{-1};
    /// Specify the configuration section that should be used
    std::string configSection{};

  public:
    std::string
    to_config(const App * /*app*/, bool default_also, bool write_description, std::string prefix) const override;

    std::vector<ConfigItem> from_config(std::istream &input) const override;
    /// Specify the configuration for comment characters
    ConfigBase *comment(char cchar) {
        commentChar = cchar;
        return this;
    }
    /// Specify the start and end characters for an array
    ConfigBase *arrayBounds(char aStart, char aEnd) {
        arrayStart = aStart;
        arrayEnd = aEnd;
        return this;
    }
    /// Specify the delimiter character for an array
    ConfigBase *arrayDelimiter(char aSep) {
        arraySeparator = aSep;
        return this;
    }
    /// Specify the delimiter between a name and value
    ConfigBase *valueSeparator(char vSep) {
        valueDelimiter = vSep;
        return this;
    }
    /// Specify the quote characters used around strings and characters
    ConfigBase *quoteCharacter(char qString, char qChar) {
        stringQuote = qString;
        characterQuote = qChar;
        return this;
    }
    /// Specify the maximum number of parents
    ConfigBase *maxLayers(uint8_t layers) {
        maximumLayers = layers;
        return this;
    }
    /// Specify the separator to use for parent layers
    ConfigBase *parentSeparator(char sep) {
        parentSeparatorChar = sep;
        return this;
    }
    /// get a reference to the configuration section
    std::string &sectionRef() { return configSection; }
    /// get the section
    CLI11_NODISCARD const std::string &section() const { return configSection; }
    /// specify a particular section of the configuration file to use
    ConfigBase *section(const std::string &sectionName) {
        configSection = sectionName;
        return this;
    }

    /// get a reference to the configuration index
    int16_t &indexRef() { return configIndex; }
    /// get the section index
    CLI11_NODISCARD int16_t index() const { return configIndex; }
    /// specify a particular index in the section to use (-1) for all sections to use
    ConfigBase *index(int16_t sectionIndex) {
        configIndex = sectionIndex;
        return this;
    }
};

/// the default Config is the TOML file format
using ConfigTOML = ConfigBase;

/// ConfigINI generates a "standard" INI compliant output
class ConfigINI : public ConfigTOML {

  public:
    ConfigINI() {
        commentChar = ';';
        arrayStart = '\0';
        arrayEnd = '\0';
        arraySeparator = ' ';
        valueDelimiter = '=';
    }
};



class Option;

/// @defgroup validator_group Validators

/// @brief Some validators that are provided
///
/// These are simple `std::string(const std::string&)` validators that are useful. They return
/// a string if the validation fails. A custom struct is provided, as well, with the same user
/// semantics, but with the ability to provide a new type name.
/// @{

///
class Validator {
  protected:
    /// This is the description function, if empty the description_ will be used
    std::function<std::string()> desc_function_{[]() { return std::string{}; }};

    /// This is the base function that is to be called.
    /// Returns a string error message if validation fails.
    std::function<std::string(std::string &)> func_{[](std::string &) { return std::string{}; }};
    /// The name for search purposes of the Validator
    std::string name_{};
    /// A Validator will only apply to an indexed value (-1 is all elements)
    int application_index_ = -1;
    /// Enable for Validator to allow it to be disabled if need be
    bool active_{true};
    /// specify that a validator should not modify the input
    bool non_modifying_{false};

    Validator(std::string validator_desc, std::function<std::string(std::string &)> func)
        : desc_function_([validator_desc]() { return validator_desc; }), func_(std::move(func)) {}

  public:
    Validator() = default;
    /// Construct a Validator with just the description string
    explicit Validator(std::string validator_desc) : desc_function_([validator_desc]() { return validator_desc; }) {}
    /// Construct Validator from basic information
    Validator(std::function<std::string(std::string &)> op, std::string validator_desc, std::string validator_name = "")
        : desc_function_([validator_desc]() { return validator_desc; }), func_(std::move(op)),
          name_(std::move(validator_name)) {}
    /// Set the Validator operation function
    Validator &operation(std::function<std::string(std::string &)> op) {
        func_ = std::move(op);
        return *this;
    }
    /// This is the required operator for a Validator - provided to help
    /// users (CLI11 uses the member `func` directly)
    std::string operator()(std::string &str) const;

    /// This is the required operator for a Validator - provided to help
    /// users (CLI11 uses the member `func` directly)
    std::string operator()(const std::string &str) const {
        std::string value = str;
        return (active_) ? func_(value) : std::string{};
    }

    /// Specify the type string
    Validator &description(std::string validator_desc) {
        desc_function_ = [validator_desc]() { return validator_desc; };
        return *this;
    }
    /// Specify the type string
    CLI11_NODISCARD Validator description(std::string validator_desc) const;

    /// Generate type description information for the Validator
    CLI11_NODISCARD std::string get_description() const {
        if(active_) {
            return desc_function_();
        }
        return std::string{};
    }
    /// Specify the type string
    Validator &name(std::string validator_name) {
        name_ = std::move(validator_name);
        return *this;
    }
    /// Specify the type string
    CLI11_NODISCARD Validator name(std::string validator_name) const {
        Validator newval(*this);
        newval.name_ = std::move(validator_name);
        return newval;
    }
    /// Get the name of the Validator
    CLI11_NODISCARD const std::string &get_name() const { return name_; }
    /// Specify whether the Validator is active or not
    Validator &active(bool active_val = true) {
        active_ = active_val;
        return *this;
    }
    /// Specify whether the Validator is active or not
    CLI11_NODISCARD Validator active(bool active_val = true) const {
        Validator newval(*this);
        newval.active_ = active_val;
        return newval;
    }

    /// Specify whether the Validator can be modifying or not
    Validator &non_modifying(bool no_modify = true) {
        non_modifying_ = no_modify;
        return *this;
    }
    /// Specify the application index of a validator
    Validator &application_index(int app_index) {
        application_index_ = app_index;
        return *this;
    }
    /// Specify the application index of a validator
    CLI11_NODISCARD Validator application_index(int app_index) const {
        Validator newval(*this);
        newval.application_index_ = app_index;
        return newval;
    }
    /// Get the current value of the application index
    CLI11_NODISCARD int get_application_index() const { return application_index_; }
    /// Get a boolean if the validator is active
    CLI11_NODISCARD bool get_active() const { return active_; }

    /// Get a boolean if the validator is allowed to modify the input returns true if it can modify the input
    CLI11_NODISCARD bool get_modifying() const { return !non_modifying_; }

    /// Combining validators is a new validator. Type comes from left validator if function, otherwise only set if the
    /// same.
    Validator operator&(const Validator &other) const;

    /// Combining validators is a new validator. Type comes from left validator if function, otherwise only set if the
    /// same.
    Validator operator|(const Validator &other) const;

    /// Create a validator that fails when a given validator succeeds
    Validator operator!() const;

  private:
    void _merge_description(const Validator &val1, const Validator &val2, const std::string &merger);
};

/// Class wrapping some of the accessors of Validator
class CustomValidator : public Validator {
  public:
};
// The implementation of the built in validators is using the Validator class;
// the user is only expected to use the const (static) versions (since there's no setup).
// Therefore, this is in detail.
namespace detail {

/// CLI enumeration of different file types
enum class path_type { nonexistent, file, directory };

/// get the type of the path from a file name
CLI11_INLINE path_type check_path(const char *file) noexcept;

/// Check for an existing file (returns error message if check fails)
class ExistingFileValidator : public Validator {
  public:
    ExistingFileValidator();
};

/// Check for an existing directory (returns error message if check fails)
class ExistingDirectoryValidator : public Validator {
  public:
    ExistingDirectoryValidator();
};

/// Check for an existing path
class ExistingPathValidator : public Validator {
  public:
    ExistingPathValidator();
};

/// Check for an non-existing path
class NonexistentPathValidator : public Validator {
  public:
    NonexistentPathValidator();
};

/// Validate the given string is a legal ipv4 address
class IPV4Validator : public Validator {
  public:
    IPV4Validator();
};

}  // namespace detail

// Static is not needed here, because global const implies static.

/// Check for existing file (returns error message if check fails)
const detail::ExistingFileValidator ExistingFile;

/// Check for an existing directory (returns error message if check fails)
const detail::ExistingDirectoryValidator ExistingDirectory;

/// Check for an existing path
const detail::ExistingPathValidator ExistingPath;

/// Check for an non-existing path
const detail::NonexistentPathValidator NonexistentPath;

/// Check for an IP4 address
const detail::IPV4Validator ValidIPV4;

/// Validate the input as a particular type
template <typename DesiredType> class TypeValidator : public Validator {
  public:
    explicit TypeValidator(const std::string &validator_name)
        : Validator(validator_name, [](std::string &input_string) {
              auto val = DesiredType();
              if(!detail::lexical_cast(input_string, val)) {
                  return std::string("Failed parsing ") + input_string + " as a " + detail::type_name<DesiredType>();
              }
              return std::string();
          }) {}
    TypeValidator() : TypeValidator(detail::type_name<DesiredType>()) {}
};

/// Check for a number
const TypeValidator<double> Number("NUMBER");

/// Modify a path if the file is a particular default location, can be used as Check or transform
/// with the error return optionally disabled
class FileOnDefaultPath : public Validator {
  public:
    explicit FileOnDefaultPath(std::string default_path, bool enableErrorReturn = true);
};

/// Produce a range (factory). Min and max are inclusive.
class Range : public Validator {
  public:
    /// This produces a range with min and max inclusive.
    ///
    /// Note that the constructor is templated, but the struct is not, so C++17 is not
    /// needed to provide nice syntax for Range(a,b).
    template <typename T>
    Range(T min_val, T max_val, const std::string &validator_name = std::string{}) : Validator(validator_name) {
        if(validator_name.empty()) {
            std::stringstream out;
            out << detail::type_name<T>() << " in [" << min_val << " - " << max_val << "]";
            description(out.str());
        }

        func_ = [min_val, max_val](std::string &input) {
            T val;
            bool converted = detail::lexical_cast(input, val);
            if((!converted) || (val < min_val || val > max_val)) {
                std::stringstream out;
                out << "Value " << input << " not in range [";
                out << min_val << " - " << max_val << "]";
                return out.str();
            }
            return std::string{};
        };
    }

    /// Range of one value is 0 to value
    template <typename T>
    explicit Range(T max_val, const std::string &validator_name = std::string{})
        : Range(static_cast<T>(0), max_val, validator_name) {}
};

/// Check for a non negative number
const Range NonNegativeNumber((std::numeric_limits<double>::max)(), "NONNEGATIVE");

/// Check for a positive valued number (val>0.0), <double>::min  here is the smallest positive number
const Range PositiveNumber((std::numeric_limits<double>::min)(), (std::numeric_limits<double>::max)(), "POSITIVE");

/// Produce a bounded range (factory). Min and max are inclusive.
class Bound : public Validator {
  public:
    /// This bounds a value with min and max inclusive.
    ///
    /// Note that the constructor is templated, but the struct is not, so C++17 is not
    /// needed to provide nice syntax for Range(a,b).
    template <typename T> Bound(T min_val, T max_val) {
        std::stringstream out;
        out << detail::type_name<T>() << " bounded to [" << min_val << " - " << max_val << "]";
        description(out.str());

        func_ = [min_val, max_val](std::string &input) {
            T val;
            bool converted = detail::lexical_cast(input, val);
            if(!converted) {
                return std::string("Value ") + input + " could not be converted";
            }
            if(val < min_val)
                input = detail::to_string(min_val);
            else if(val > max_val)
                input = detail::to_string(max_val);

            return std::string{};
        };
    }

    /// Range of one value is 0 to value
    template <typename T> explicit Bound(T max_val) : Bound(static_cast<T>(0), max_val) {}
};

namespace detail {
template <typename T,
          enable_if_t<is_copyable_ptr<typename std::remove_reference<T>::type>::value, detail::enabler> = detail::dummy>
auto smart_deref(T value) -> decltype(*value) {
    return *value;
}

template <
    typename T,
    enable_if_t<!is_copyable_ptr<typename std::remove_reference<T>::type>::value, detail::enabler> = detail::dummy>
typename std::remove_reference<T>::type &smart_deref(T &value) {
    return value;
}
/// Generate a string representation of a set
template <typename T> std::string generate_set(const T &set) {
    using element_t = typename detail::element_type<T>::type;
    using iteration_type_t = typename detail::pair_adaptor<element_t>::value_type;  // the type of the object pair
    std::string out(1, '{');
    out.append(detail::join(
        detail::smart_deref(set),
        [](const iteration_type_t &v) { return detail::pair_adaptor<element_t>::first(v); },
        ","));
    out.push_back('}');
    return out;
}

/// Generate a string representation of a map
template <typename T> std::string generate_map(const T &map, bool key_only = false) {
    using element_t = typename detail::element_type<T>::type;
    using iteration_type_t = typename detail::pair_adaptor<element_t>::value_type;  // the type of the object pair
    std::string out(1, '{');
    out.append(detail::join(
        detail::smart_deref(map),
        [key_only](const iteration_type_t &v) {
            std::string res{detail::to_string(detail::pair_adaptor<element_t>::first(v))};

            if(!key_only) {
                res.append("->");
                res += detail::to_string(detail::pair_adaptor<element_t>::second(v));
            }
            return res;
        },
        ","));
    out.push_back('}');
    return out;
}

template <typename C, typename V> struct has_find {
    template <typename CC, typename VV>
    static auto test(int) -> decltype(std::declval<CC>().find(std::declval<VV>()), std::true_type());
    template <typename, typename> static auto test(...) -> decltype(std::false_type());

    static const auto value = decltype(test<C, V>(0))::value;
    using type = std::integral_constant<bool, value>;
};

/// A search function
template <typename T, typename V, enable_if_t<!has_find<T, V>::value, detail::enabler> = detail::dummy>
auto search(const T &set, const V &val) -> std::pair<bool, decltype(std::begin(detail::smart_deref(set)))> {
    using element_t = typename detail::element_type<T>::type;
    auto &setref = detail::smart_deref(set);
    auto it = std::find_if(std::begin(setref), std::end(setref), [&val](decltype(*std::begin(setref)) v) {
        return (detail::pair_adaptor<element_t>::first(v) == val);
    });
    return {(it != std::end(setref)), it};
}

/// A search function that uses the built in find function
template <typename T, typename V, enable_if_t<has_find<T, V>::value, detail::enabler> = detail::dummy>
auto search(const T &set, const V &val) -> std::pair<bool, decltype(std::begin(detail::smart_deref(set)))> {
    auto &setref = detail::smart_deref(set);
    auto it = setref.find(val);
    return {(it != std::end(setref)), it};
}

/// A search function with a filter function
template <typename T, typename V>
auto search(const T &set, const V &val, const std::function<V(V)> &filter_function)
    -> std::pair<bool, decltype(std::begin(detail::smart_deref(set)))> {
    using element_t = typename detail::element_type<T>::type;
    // do the potentially faster first search
    auto res = search(set, val);
    if((res.first) || (!(filter_function))) {
        return res;
    }
    // if we haven't found it do the longer linear search with all the element translations
    auto &setref = detail::smart_deref(set);
    auto it = std::find_if(std::begin(setref), std::end(setref), [&](decltype(*std::begin(setref)) v) {
        V a{detail::pair_adaptor<element_t>::first(v)};
        a = filter_function(a);
        return (a == val);
    });
    return {(it != std::end(setref)), it};
}

// the following suggestion was made by Nikita Ofitserov(@himikof)
// done in templates to prevent compiler warnings on negation of unsigned numbers

/// Do a check for overflow on signed numbers
template <typename T>
inline typename std::enable_if<std::is_signed<T>::value, T>::type overflowCheck(const T &a, const T &b) {
    if((a > 0) == (b > 0)) {
        return ((std::numeric_limits<T>::max)() / (std::abs)(a) < (std::abs)(b));
    }
    return ((std::numeric_limits<T>::min)() / (std::abs)(a) > -(std::abs)(b));
}
/// Do a check for overflow on unsigned numbers
template <typename T>
inline typename std::enable_if<!std::is_signed<T>::value, T>::type overflowCheck(const T &a, const T &b) {
    return ((std::numeric_limits<T>::max)() / a < b);
}

/// Performs a *= b; if it doesn't cause integer overflow. Returns false otherwise.
template <typename T> typename std::enable_if<std::is_integral<T>::value, bool>::type checked_multiply(T &a, T b) {
    if(a == 0 || b == 0 || a == 1 || b == 1) {
        a *= b;
        return true;
    }
    if(a == (std::numeric_limits<T>::min)() || b == (std::numeric_limits<T>::min)()) {
        return false;
    }
    if(overflowCheck(a, b)) {
        return false;
    }
    a *= b;
    return true;
}

/// Performs a *= b; if it doesn't equal infinity. Returns false otherwise.
template <typename T>
typename std::enable_if<std::is_floating_point<T>::value, bool>::type checked_multiply(T &a, T b) {
    T c = a * b;
    if(std::isinf(c) && !std::isinf(a) && !std::isinf(b)) {
        return false;
    }
    a = c;
    return true;
}

}  // namespace detail
/// Verify items are in a set
class IsMember : public Validator {
  public:
    using filter_fn_t = std::function<std::string(std::string)>;

    /// This allows in-place construction using an initializer list
    template <typename T, typename... Args>
    IsMember(std::initializer_list<T> values, Args &&...args)
        : IsMember(std::vector<T>(values), std::forward<Args>(args)...) {}

    /// This checks to see if an item is in a set (empty function)
    template <typename T> explicit IsMember(T &&set) : IsMember(std::forward<T>(set), nullptr) {}

    /// This checks to see if an item is in a set: pointer or copy version. You can pass in a function that will filter
    /// both sides of the comparison before computing the comparison.
    template <typename T, typename F> explicit IsMember(T set, F filter_function) {

        // Get the type of the contained item - requires a container have ::value_type
        // if the type does not have first_type and second_type, these are both value_type
        using element_t = typename detail::element_type<T>::type;             // Removes (smart) pointers if needed
        using item_t = typename detail::pair_adaptor<element_t>::first_type;  // Is value_type if not a map

        using local_item_t = typename IsMemberType<item_t>::type;  // This will convert bad types to good ones
                                                                   // (const char * to std::string)

        // Make a local copy of the filter function, using a std::function if not one already
        std::function<local_item_t(local_item_t)> filter_fn = filter_function;

        // This is the type name for help, it will take the current version of the set contents
        desc_function_ = [set]() { return detail::generate_set(detail::smart_deref(set)); };

        // This is the function that validates
        // It stores a copy of the set pointer-like, so shared_ptr will stay alive
        func_ = [set, filter_fn](std::string &input) {
            local_item_t b;
            if(!detail::lexical_cast(input, b)) {
                throw ValidationError(input);  // name is added later
            }
            if(filter_fn) {
                b = filter_fn(b);
            }
            auto res = detail::search(set, b, filter_fn);
            if(res.first) {
                // Make sure the version in the input string is identical to the one in the set
                if(filter_fn) {
                    input = detail::value_string(detail::pair_adaptor<element_t>::first(*(res.second)));
                }

                // Return empty error string (success)
                return std::string{};
            }

            // If you reach this point, the result was not found
            return input + " not in " + detail::generate_set(detail::smart_deref(set));
        };
    }

    /// You can pass in as many filter functions as you like, they nest (string only currently)
    template <typename T, typename... Args>
    IsMember(T &&set, filter_fn_t filter_fn_1, filter_fn_t filter_fn_2, Args &&...other)
        : IsMember(
              std::forward<T>(set),
              [filter_fn_1, filter_fn_2](std::string a) { return filter_fn_2(filter_fn_1(a)); },
              other...) {}
};

/// definition of the default transformation object
template <typename T> using TransformPairs = std::vector<std::pair<std::string, T>>;

/// Translate named items to other or a value set
class Transformer : public Validator {
  public:
    using filter_fn_t = std::function<std::string(std::string)>;

    /// This allows in-place construction
    template <typename... Args>
    Transformer(std::initializer_list<std::pair<std::string, std::string>> values, Args &&...args)
        : Transformer(TransformPairs<std::string>(values), std::forward<Args>(args)...) {}

    /// direct map of std::string to std::string
    template <typename T> explicit Transformer(T &&mapping) : Transformer(std::forward<T>(mapping), nullptr) {}

    /// This checks to see if an item is in a set: pointer or copy version. You can pass in a function that will filter
    /// both sides of the comparison before computing the comparison.
    template <typename T, typename F> explicit Transformer(T mapping, F filter_function) {

        static_assert(detail::pair_adaptor<typename detail::element_type<T>::type>::value,
                      "mapping must produce value pairs");
        // Get the type of the contained item - requires a container have ::value_type
        // if the type does not have first_type and second_type, these are both value_type
        using element_t = typename detail::element_type<T>::type;             // Removes (smart) pointers if needed
        using item_t = typename detail::pair_adaptor<element_t>::first_type;  // Is value_type if not a map
        using local_item_t = typename IsMemberType<item_t>::type;             // Will convert bad types to good ones
                                                                              // (const char * to std::string)

        // Make a local copy of the filter function, using a std::function if not one already
        std::function<local_item_t(local_item_t)> filter_fn = filter_function;

        // This is the type name for help, it will take the current version of the set contents
        desc_function_ = [mapping]() { return detail::generate_map(detail::smart_deref(mapping)); };

        func_ = [mapping, filter_fn](std::string &input) {
            local_item_t b;
            if(!detail::lexical_cast(input, b)) {
                return std::string();
                // there is no possible way we can match anything in the mapping if we can't convert so just return
            }
            if(filter_fn) {
                b = filter_fn(b);
            }
            auto res = detail::search(mapping, b, filter_fn);
            if(res.first) {
                input = detail::value_string(detail::pair_adaptor<element_t>::second(*res.second));
            }
            return std::string{};
        };
    }

    /// You can pass in as many filter functions as you like, they nest
    template <typename T, typename... Args>
    Transformer(T &&mapping, filter_fn_t filter_fn_1, filter_fn_t filter_fn_2, Args &&...other)
        : Transformer(
              std::forward<T>(mapping),
              [filter_fn_1, filter_fn_2](std::string a) { return filter_fn_2(filter_fn_1(a)); },
              other...) {}
};

/// translate named items to other or a value set
class CheckedTransformer : public Validator {
  public:
    using filter_fn_t = std::function<std::string(std::string)>;

    /// This allows in-place construction
    template <typename... Args>
    CheckedTransformer(std::initializer_list<std::pair<std::string, std::string>> values, Args &&...args)
        : CheckedTransformer(TransformPairs<std::string>(values), std::forward<Args>(args)...) {}

    /// direct map of std::string to std::string
    template <typename T> explicit CheckedTransformer(T mapping) : CheckedTransformer(std::move(mapping), nullptr) {}

    /// This checks to see if an item is in a set: pointer or copy version. You can pass in a function that will filter
    /// both sides of the comparison before computing the comparison.
    template <typename T, typename F> explicit CheckedTransformer(T mapping, F filter_function) {

        static_assert(detail::pair_adaptor<typename detail::element_type<T>::type>::value,
                      "mapping must produce value pairs");
        // Get the type of the contained item - requires a container have ::value_type
        // if the type does not have first_type and second_type, these are both value_type
        using element_t = typename detail::element_type<T>::type;             // Removes (smart) pointers if needed
        using item_t = typename detail::pair_adaptor<element_t>::first_type;  // Is value_type if not a map
        using local_item_t = typename IsMemberType<item_t>::type;             // Will convert bad types to good ones
                                                                              // (const char * to std::string)
        using iteration_type_t = typename detail::pair_adaptor<element_t>::value_type;  // the type of the object pair

        // Make a local copy of the filter function, using a std::function if not one already
        std::function<local_item_t(local_item_t)> filter_fn = filter_function;

        auto tfunc = [mapping]() {
            std::string out("value in ");
            out += detail::generate_map(detail::smart_deref(mapping)) + " OR {";
            out += detail::join(
                detail::smart_deref(mapping),
                [](const iteration_type_t &v) { return detail::to_string(detail::pair_adaptor<element_t>::second(v)); },
                ",");
            out.push_back('}');
            return out;
        };

        desc_function_ = tfunc;

        func_ = [mapping, tfunc, filter_fn](std::string &input) {
            local_item_t b;
            bool converted = detail::lexical_cast(input, b);
            if(converted) {
                if(filter_fn) {
                    b = filter_fn(b);
                }
                auto res = detail::search(mapping, b, filter_fn);
                if(res.first) {
                    input = detail::value_string(detail::pair_adaptor<element_t>::second(*res.second));
                    return std::string{};
                }
            }
            for(const auto &v : detail::smart_deref(mapping)) {
                auto output_string = detail::value_string(detail::pair_adaptor<element_t>::second(v));
                if(output_string == input) {
                    return std::string();
                }
            }

            return "Check " + input + " " + tfunc() + " FAILED";
        };
    }

    /// You can pass in as many filter functions as you like, they nest
    template <typename T, typename... Args>
    CheckedTransformer(T &&mapping, filter_fn_t filter_fn_1, filter_fn_t filter_fn_2, Args &&...other)
        : CheckedTransformer(
              std::forward<T>(mapping),
              [filter_fn_1, filter_fn_2](std::string a) { return filter_fn_2(filter_fn_1(a)); },
              other...) {}
};

/// Helper function to allow ignore_case to be passed to IsMember or Transform
inline std::string ignore_case(std::string item) { return detail::to_lower(item); }

/// Helper function to allow ignore_underscore to be passed to IsMember or Transform
inline std::string ignore_underscore(std::string item) { return detail::remove_underscore(item); }

/// Helper function to allow checks to ignore spaces to be passed to IsMember or Transform
inline std::string ignore_space(std::string item) {
    item.erase(std::remove(std::begin(item), std::end(item), ' '), std::end(item));
    item.erase(std::remove(std::begin(item), std::end(item), '\t'), std::end(item));
    return item;
}

/// Multiply a number by a factor using given mapping.
/// Can be used to write transforms for SIZE or DURATION inputs.
///
/// Example:
///   With mapping = `{"b"->1, "kb"->1024, "mb"->1024*1024}`
///   one can recognize inputs like "100", "12kb", "100 MB",
///   that will be automatically transformed to 100, 14448, 104857600.
///
/// Output number type matches the type in the provided mapping.
/// Therefore, if it is required to interpret real inputs like "0.42 s",
/// the mapping should be of a type <string, float> or <string, double>.
class AsNumberWithUnit : public Validator {
  public:
    /// Adjust AsNumberWithUnit behavior.
    /// CASE_SENSITIVE/CASE_INSENSITIVE controls how units are matched.
    /// UNIT_OPTIONAL/UNIT_REQUIRED throws ValidationError
    ///   if UNIT_REQUIRED is set and unit literal is not found.
    enum Options {
        CASE_SENSITIVE = 0,
        CASE_INSENSITIVE = 1,
        UNIT_OPTIONAL = 0,
        UNIT_REQUIRED = 2,
        DEFAULT = CASE_INSENSITIVE | UNIT_OPTIONAL
    };

    template <typename Number>
    explicit AsNumberWithUnit(std::map<std::string, Number> mapping,
                              Options opts = DEFAULT,
                              const std::string &unit_name = "UNIT") {
        description(generate_description<Number>(unit_name, opts));
        validate_mapping(mapping, opts);

        // transform function
        func_ = [mapping, opts](std::string &input) -> std::string {
            Number num{};

            detail::rtrim(input);
            if(input.empty()) {
                throw ValidationError("Input is empty");
            }

            // Find split position between number and prefix
            auto unit_begin = input.end();
            while(unit_begin > input.begin() && std::isalpha(*(unit_begin - 1), std::locale())) {
                --unit_begin;
            }

            std::string unit{unit_begin, input.end()};
            input.resize(static_cast<std::size_t>(std::distance(input.begin(), unit_begin)));
            detail::trim(input);

            if(opts & UNIT_REQUIRED && unit.empty()) {
                throw ValidationError("Missing mandatory unit");
            }
            if(opts & CASE_INSENSITIVE) {
                unit = detail::to_lower(unit);
            }
            if(unit.empty()) {
                if(!detail::lexical_cast(input, num)) {
                    throw ValidationError(std::string("Value ") + input + " could not be converted to " +
                                          detail::type_name<Number>());
                }
                // No need to modify input if no unit passed
                return {};
            }

            // find corresponding factor
            auto it = mapping.find(unit);
            if(it == mapping.end()) {
                throw ValidationError(unit +
                                      " unit not recognized. "
                                      "Allowed values: " +
                                      detail::generate_map(mapping, true));
            }

            if(!input.empty()) {
                bool converted = detail::lexical_cast(input, num);
                if(!converted) {
                    throw ValidationError(std::string("Value ") + input + " could not be converted to " +
                                          detail::type_name<Number>());
                }
                // perform safe multiplication
                bool ok = detail::checked_multiply(num, it->second);
                if(!ok) {
                    throw ValidationError(detail::to_string(num) + " multiplied by " + unit +
                                          " factor would cause number overflow. Use smaller value.");
                }
            } else {
                num = static_cast<Number>(it->second);
            }

            input = detail::to_string(num);

            return {};
        };
    }

  private:
    /// Check that mapping contains valid units.
    /// Update mapping for CASE_INSENSITIVE mode.
    template <typename Number> static void validate_mapping(std::map<std::string, Number> &mapping, Options opts) {
        for(auto &kv : mapping) {
            if(kv.first.empty()) {
                throw ValidationError("Unit must not be empty.");
            }
            if(!detail::isalpha(kv.first)) {
                throw ValidationError("Unit must contain only letters.");
            }
        }

        // make all units lowercase if CASE_INSENSITIVE
        if(opts & CASE_INSENSITIVE) {
            std::map<std::string, Number> lower_mapping;
            for(auto &kv : mapping) {
                auto s = detail::to_lower(kv.first);
                if(lower_mapping.count(s)) {
                    throw ValidationError(std::string("Several matching lowercase unit representations are found: ") +
                                          s);
                }
                lower_mapping[detail::to_lower(kv.first)] = kv.second;
            }
            mapping = std::move(lower_mapping);
        }
    }

    /// Generate description like this: NUMBER [UNIT]
    template <typename Number> static std::string generate_description(const std::string &name, Options opts) {
        std::stringstream out;
        out << detail::type_name<Number>() << ' ';
        if(opts & UNIT_REQUIRED) {
            out << name;
        } else {
            out << '[' << name << ']';
        }
        return out.str();
    }
};

inline AsNumberWithUnit::Options operator|(const AsNumberWithUnit::Options &a, const AsNumberWithUnit::Options &b) {
    return static_cast<AsNumberWithUnit::Options>(static_cast<int>(a) | static_cast<int>(b));
}

/// Converts a human-readable size string (with unit literal) to uin64_t size.
/// Example:
///   "100" => 100
///   "1 b" => 100
///   "10Kb" => 10240 // you can configure this to be interpreted as kilobyte (*1000) or kibibyte (*1024)
///   "10 KB" => 10240
///   "10 kb" => 10240
///   "10 kib" => 10240 // *i, *ib are always interpreted as *bibyte (*1024)
///   "10kb" => 10240
///   "2 MB" => 2097152
///   "2 EiB" => 2^61 // Units up to exibyte are supported
class AsSizeValue : public AsNumberWithUnit {
  public:
    using result_t = std::uint64_t;

    /// If kb_is_1000 is true,
    /// interpret 'kb', 'k' as 1000 and 'kib', 'ki' as 1024
    /// (same applies to higher order units as well).
    /// Otherwise, interpret all literals as factors of 1024.
    /// The first option is formally correct, but
    /// the second interpretation is more wide-spread
    /// (see https://en.wikipedia.org/wiki/Binary_prefix).
    explicit AsSizeValue(bool kb_is_1000);

  private:
    /// Get <size unit, factor> mapping
    static std::map<std::string, result_t> init_mapping(bool kb_is_1000);

    /// Cache calculated mapping
    static std::map<std::string, result_t> get_mapping(bool kb_is_1000);
};

namespace detail {
/// Split a string into a program name and command line arguments
/// the string is assumed to contain a file name followed by other arguments
/// the return value contains is a pair with the first argument containing the program name and the second
/// everything else.
CLI11_INLINE std::pair<std::string, std::string> split_program_name(std::string commandline);

}  // namespace detail
/// @}




CLI11_INLINE std::string Validator::operator()(std::string &str) const {
    std::string retstring;
    if(active_) {
        if(non_modifying_) {
            std::string value = str;
            retstring = func_(value);
        } else {
            retstring = func_(str);
        }
    }
    return retstring;
}

CLI11_NODISCARD CLI11_INLINE Validator Validator::description(std::string validator_desc) const {
    Validator newval(*this);
    newval.desc_function_ = [validator_desc]() { return validator_desc; };
    return newval;
}

CLI11_INLINE Validator Validator::operator&(const Validator &other) const {
    Validator newval;

    newval._merge_description(*this, other, " AND ");

    // Give references (will make a copy in lambda function)
    const std::function<std::string(std::string & filename)> &f1 = func_;
    const std::function<std::string(std::string & filename)> &f2 = other.func_;

    newval.func_ = [f1, f2](std::string &input) {
        std::string s1 = f1(input);
        std::string s2 = f2(input);
        if(!s1.empty() && !s2.empty())
            return std::string("(") + s1 + ") AND (" + s2 + ")";
        return s1 + s2;
    };

    newval.active_ = active_ && other.active_;
    newval.application_index_ = application_index_;
    return newval;
}

CLI11_INLINE Validator Validator::operator|(const Validator &other) const {
    Validator newval;

    newval._merge_description(*this, other, " OR ");

    // Give references (will make a copy in lambda function)
    const std::function<std::string(std::string &)> &f1 = func_;
    const std::function<std::string(std::string &)> &f2 = other.func_;

    newval.func_ = [f1, f2](std::string &input) {
        std::string s1 = f1(input);
        std::string s2 = f2(input);
        if(s1.empty() || s2.empty())
            return std::string();

        return std::string("(") + s1 + ") OR (" + s2 + ")";
    };
    newval.active_ = active_ && other.active_;
    newval.application_index_ = application_index_;
    return newval;
}

CLI11_INLINE Validator Validator::operator!() const {
    Validator newval;
    const std::function<std::string()> &dfunc1 = desc_function_;
    newval.desc_function_ = [dfunc1]() {
        auto str = dfunc1();
        return (!str.empty()) ? std::string("NOT ") + str : std::string{};
    };
    // Give references (will make a copy in lambda function)
    const std::function<std::string(std::string & res)> &f1 = func_;

    newval.func_ = [f1, dfunc1](std::string &test) -> std::string {
        std::string s1 = f1(test);
        if(s1.empty()) {
            return std::string("check ") + dfunc1() + " succeeded improperly";
        }
        return std::string{};
    };
    newval.active_ = active_;
    newval.application_index_ = application_index_;
    return newval;
}

CLI11_INLINE void
Validator::_merge_description(const Validator &val1, const Validator &val2, const std::string &merger) {

    const std::function<std::string()> &dfunc1 = val1.desc_function_;
    const std::function<std::string()> &dfunc2 = val2.desc_function_;

    desc_function_ = [=]() {
        std::string f1 = dfunc1();
        std::string f2 = dfunc2();
        if((f1.empty()) || (f2.empty())) {
            return f1 + f2;
        }
        return std::string(1, '(') + f1 + ')' + merger + '(' + f2 + ')';
    };
}

namespace detail {

#if defined CLI11_HAS_FILESYSTEM && CLI11_HAS_FILESYSTEM > 0
CLI11_INLINE path_type check_path(const char *file) noexcept {
    std::error_code ec;
    auto stat = std::filesystem::status(file, ec);
    if(ec) {
        return path_type::nonexistent;
    }
    switch(stat.type()) {
    case std::filesystem::file_type::none:  // LCOV_EXCL_LINE
    case std::filesystem::file_type::not_found:
        return path_type::nonexistent;
    case std::filesystem::file_type::directory:
        return path_type::directory;
    case std::filesystem::file_type::symlink:
    case std::filesystem::file_type::block:
    case std::filesystem::file_type::character:
    case std::filesystem::file_type::fifo:
    case std::filesystem::file_type::socket:
    case std::filesystem::file_type::regular:
    case std::filesystem::file_type::unknown:
    default:
        return path_type::file;
    }
}
#else
CLI11_INLINE path_type check_path(const char *file) noexcept {
#if defined(_MSC_VER)
    struct __stat64 buffer;
    if(_stat64(file, &buffer) == 0) {
        return ((buffer.st_mode & S_IFDIR) != 0) ? path_type::directory : path_type::file;
    }
#else
    struct stat buffer;
    if(stat(file, &buffer) == 0) {
        return ((buffer.st_mode & S_IFDIR) != 0) ? path_type::directory : path_type::file;
    }
#endif
    return path_type::nonexistent;
}
#endif

CLI11_INLINE ExistingFileValidator::ExistingFileValidator() : Validator("FILE") {
    func_ = [](std::string &filename) {
        auto path_result = check_path(filename.c_str());
        if(path_result == path_type::nonexistent) {
            return "File does not exist: " + filename;
        }
        if(path_result == path_type::directory) {
            return "File is actually a directory: " + filename;
        }
        return std::string();
    };
}

CLI11_INLINE ExistingDirectoryValidator::ExistingDirectoryValidator() : Validator("DIR") {
    func_ = [](std::string &filename) {
        auto path_result = check_path(filename.c_str());
        if(path_result == path_type::nonexistent) {
            return "Directory does not exist: " + filename;
        }
        if(path_result == path_type::file) {
            return "Directory is actually a file: " + filename;
        }
        return std::string();
    };
}

CLI11_INLINE ExistingPathValidator::ExistingPathValidator() : Validator("PATH(existing)") {
    func_ = [](std::string &filename) {
        auto path_result = check_path(filename.c_str());
        if(path_result == path_type::nonexistent) {
            return "Path does not exist: " + filename;
        }
        return std::string();
    };
}

CLI11_INLINE NonexistentPathValidator::NonexistentPathValidator() : Validator("PATH(non-existing)") {
    func_ = [](std::string &filename) {
        auto path_result = check_path(filename.c_str());
        if(path_result != path_type::nonexistent) {
            return "Path already exists: " + filename;
        }
        return std::string();
    };
}

CLI11_INLINE IPV4Validator::IPV4Validator() : Validator("IPV4") {
    func_ = [](std::string &ip_addr) {
        auto result = CLI::detail::split(ip_addr, '.');
        if(result.size() != 4) {
            return std::string("Invalid IPV4 address must have four parts (") + ip_addr + ')';
        }
        int num = 0;
        for(const auto &var : result) {
            bool retval = detail::lexical_cast(var, num);
            if(!retval) {
                return std::string("Failed parsing number (") + var + ')';
            }
            if(num < 0 || num > 255) {
                return std::string("Each IP number must be between 0 and 255 ") + var;
            }
        }
        return std::string();
    };
}

}  // namespace detail

CLI11_INLINE FileOnDefaultPath::FileOnDefaultPath(std::string default_path, bool enableErrorReturn)
    : Validator("FILE") {
    func_ = [default_path, enableErrorReturn](std::string &filename) {
        auto path_result = detail::check_path(filename.c_str());
        if(path_result == detail::path_type::nonexistent) {
            std::string test_file_path = default_path;
            if(default_path.back() != '/' && default_path.back() != '\\') {
                // Add folder separator
                test_file_path += '/';
            }
            test_file_path.append(filename);
            path_result = detail::check_path(test_file_path.c_str());
            if(path_result == detail::path_type::file) {
                filename = test_file_path;
            } else {
                if(enableErrorReturn) {
                    return "File does not exist: " + filename;
                }
            }
        }
        return std::string{};
    };
}

CLI11_INLINE AsSizeValue::AsSizeValue(bool kb_is_1000) : AsNumberWithUnit(get_mapping(kb_is_1000)) {
    if(kb_is_1000) {
        description("SIZE [b, kb(=1000b), kib(=1024b), ...]");
    } else {
        description("SIZE [b, kb(=1024b), ...]");
    }
}

CLI11_INLINE std::map<std::string, AsSizeValue::result_t> AsSizeValue::init_mapping(bool kb_is_1000) {
    std::map<std::string, result_t> m;
    result_t k_factor = kb_is_1000 ? 1000 : 1024;
    result_t ki_factor = 1024;
    result_t k = 1;
    result_t ki = 1;
    m["b"] = 1;
    for(std::string p : {"k", "m", "g", "t", "p", "e"}) {
        k *= k_factor;
        ki *= ki_factor;
        m[p] = k;
        m[p + "b"] = k;
        m[p + "i"] = ki;
        m[p + "ib"] = ki;
    }
    return m;
}

CLI11_INLINE std::map<std::string, AsSizeValue::result_t> AsSizeValue::get_mapping(bool kb_is_1000) {
    if(kb_is_1000) {
        static auto m = init_mapping(true);
        return m;
    }
    static auto m = init_mapping(false);
    return m;
}

namespace detail {

CLI11_INLINE std::pair<std::string, std::string> split_program_name(std::string commandline) {
    // try to determine the programName
    std::pair<std::string, std::string> vals;
    trim(commandline);
    auto esp = commandline.find_first_of(' ', 1);
    while(detail::check_path(commandline.substr(0, esp).c_str()) != path_type::file) {
        esp = commandline.find_first_of(' ', esp + 1);
        if(esp == std::string::npos) {
            // if we have reached the end and haven't found a valid file just assume the first argument is the
            // program name
            if(commandline[0] == '"' || commandline[0] == '\'' || commandline[0] == '`') {
                bool embeddedQuote = false;
                auto keyChar = commandline[0];
                auto end = commandline.find_first_of(keyChar, 1);
                while((end != std::string::npos) && (commandline[end - 1] == '\\')) {  // deal with escaped quotes
                    end = commandline.find_first_of(keyChar, end + 1);
                    embeddedQuote = true;
                }
                if(end != std::string::npos) {
                    vals.first = commandline.substr(1, end - 1);
                    esp = end + 1;
                    if(embeddedQuote) {
                        vals.first = find_and_replace(vals.first, std::string("\\") + keyChar, std::string(1, keyChar));
                    }
                } else {
                    esp = commandline.find_first_of(' ', 1);
                }
            } else {
                esp = commandline.find_first_of(' ', 1);
            }

            break;
        }
    }
    if(vals.first.empty()) {
        vals.first = commandline.substr(0, esp);
        rtrim(vals.first);
    }

    // strip the program name
    vals.second = (esp < commandline.length() - 1) ? commandline.substr(esp + 1) : std::string{};
    ltrim(vals.second);
    return vals;
}

}  // namespace detail
/// @}




class Option;
class App;

/// This enum signifies the type of help requested
///
/// This is passed in by App; all user classes must accept this as
/// the second argument.

enum class AppFormatMode {
    Normal,  ///< The normal, detailed help
    All,     ///< A fully expanded help
    Sub,     ///< Used when printed as part of expanded subcommand
};

/// This is the minimum requirements to run a formatter.
///
/// A user can subclass this is if they do not care at all
/// about the structure in CLI::Formatter.
class FormatterBase {
  protected:
    /// @name Options
    ///@{

    /// The width of the first column
    std::size_t column_width_{30};

    /// @brief The required help printout labels (user changeable)
    /// Values are Needs, Excludes, etc.
    std::map<std::string, std::string> labels_{};

    ///@}
    /// @name Basic
    ///@{

  public:
    FormatterBase() = default;
    FormatterBase(const FormatterBase &) = default;
    FormatterBase(FormatterBase &&) = default;
    FormatterBase &operator=(const FormatterBase &) = default;
    FormatterBase &operator=(FormatterBase &&) = default;

    /// Adding a destructor in this form to work around bug in GCC 4.7
    virtual ~FormatterBase() noexcept {}  // NOLINT(modernize-use-equals-default)

    /// This is the key method that puts together help
    virtual std::string make_help(const App *, std::string, AppFormatMode) const = 0;

    ///@}
    /// @name Setters
    ///@{

    /// Set the "REQUIRED" label
    void label(std::string key, std::string val) { labels_[key] = val; }

    /// Set the column width
    void column_width(std::size_t val) { column_width_ = val; }

    ///@}
    /// @name Getters
    ///@{

    /// Get the current value of a name (REQUIRED, etc.)
    CLI11_NODISCARD std::string get_label(std::string key) const {
        if(labels_.find(key) == labels_.end())
            return key;
        return labels_.at(key);
    }

    /// Get the current column width
    CLI11_NODISCARD std::size_t get_column_width() const { return column_width_; }

    ///@}
};

/// This is a specialty override for lambda functions
class FormatterLambda final : public FormatterBase {
    using funct_t = std::function<std::string(const App *, std::string, AppFormatMode)>;

    /// The lambda to hold and run
    funct_t lambda_;

  public:
    /// Create a FormatterLambda with a lambda function
    explicit FormatterLambda(funct_t funct) : lambda_(std::move(funct)) {}

    /// Adding a destructor (mostly to make GCC 4.7 happy)
    ~FormatterLambda() noexcept override {}  // NOLINT(modernize-use-equals-default)

    /// This will simply call the lambda function
    std::string make_help(const App *app, std::string name, AppFormatMode mode) const override {
        return lambda_(app, name, mode);
    }
};

/// This is the default Formatter for CLI11. It pretty prints help output, and is broken into quite a few
/// overridable methods, to be highly customizable with minimal effort.
class Formatter : public FormatterBase {
  public:
    Formatter() = default;
    Formatter(const Formatter &) = default;
    Formatter(Formatter &&) = default;
    Formatter &operator=(const Formatter &) = default;
    Formatter &operator=(Formatter &&) = default;

    /// @name Overridables
    ///@{

    /// This prints out a group of options with title
    ///
    CLI11_NODISCARD virtual std::string
    make_group(std::string group, bool is_positional, std::vector<const Option *> opts) const;

    /// This prints out just the positionals "group"
    virtual std::string make_positionals(const App *app) const;

    /// This prints out all the groups of options
    std::string make_groups(const App *app, AppFormatMode mode) const;

    /// This prints out all the subcommands
    virtual std::string make_subcommands(const App *app, AppFormatMode mode) const;

    /// This prints out a subcommand
    virtual std::string make_subcommand(const App *sub) const;

    /// This prints out a subcommand in help-all
    virtual std::string make_expanded(const App *sub) const;

    /// This prints out all the groups of options
    virtual std::string make_footer(const App *app) const;

    /// This displays the description line
    virtual std::string make_description(const App *app) const;

    /// This displays the usage line
    virtual std::string make_usage(const App *app, std::string name) const;

    /// This puts everything together
    std::string make_help(const App * /*app*/, std::string, AppFormatMode) const override;

    ///@}
    /// @name Options
    ///@{

    /// This prints out an option help line, either positional or optional form
    virtual std::string make_option(const Option *opt, bool is_positional) const {
        std::stringstream out;
        detail::format_help(
            out, make_option_name(opt, is_positional) + make_option_opts(opt), make_option_desc(opt), column_width_);
        return out.str();
    }

    /// @brief This is the name part of an option, Default: left column
    virtual std::string make_option_name(const Option *, bool) const;

    /// @brief This is the options part of the name, Default: combined into left column
    virtual std::string make_option_opts(const Option *) const;

    /// @brief This is the description. Default: Right column, on new line if left column too large
    virtual std::string make_option_desc(const Option *) const;

    /// @brief This is used to print the name on the USAGE line
    virtual std::string make_option_usage(const Option *opt) const;

    ///@}
};




using results_t = std::vector<std::string>;
/// callback function definition
using callback_t = std::function<bool(const results_t &)>;

class Option;
class App;

using Option_p = std::unique_ptr<Option>;
/// Enumeration of the multiOption Policy selection
enum class MultiOptionPolicy : char {
    Throw,      //!< Throw an error if any extra arguments were given
    TakeLast,   //!< take only the last Expected number of arguments
    TakeFirst,  //!< take only the first Expected number of arguments
    Join,       //!< merge all the arguments together into a single string via the delimiter character default('\n')
    TakeAll,    //!< just get all the passed argument regardless
    Sum         //!< sum all the arguments together if numerical or concatenate directly without delimiter
};

/// This is the CRTP base class for Option and OptionDefaults. It was designed this way
/// to share parts of the class; an OptionDefaults can copy to an Option.
template <typename CRTP> class OptionBase {
    friend App;

  protected:
    /// The group membership
    std::string group_ = std::string("Options");

    /// True if this is a required option
    bool required_{false};

    /// Ignore the case when matching (option, not value)
    bool ignore_case_{false};

    /// Ignore underscores when matching (option, not value)
    bool ignore_underscore_{false};

    /// Allow this option to be given in a configuration file
    bool configurable_{true};

    /// Disable overriding flag values with '=value'
    bool disable_flag_override_{false};

    /// Specify a delimiter character for vector arguments
    char delimiter_{'\0'};

    /// Automatically capture default value
    bool always_capture_default_{false};

    /// Policy for handling multiple arguments beyond the expected Max
    MultiOptionPolicy multi_option_policy_{MultiOptionPolicy::Throw};

    /// Copy the contents to another similar class (one based on OptionBase)
    template <typename T> void copy_to(T *other) const;

  public:
    // setters

    /// Changes the group membership
    CRTP *group(const std::string &name) {
        if(!detail::valid_alias_name_string(name)) {
            throw IncorrectConstruction("Group names may not contain newlines or null characters");
        }
        group_ = name;
        return static_cast<CRTP *>(this);
    }

    /// Set the option as required
    CRTP *required(bool value = true) {
        required_ = value;
        return static_cast<CRTP *>(this);
    }

    /// Support Plumbum term
    CRTP *mandatory(bool value = true) { return required(value); }

    CRTP *always_capture_default(bool value = true) {
        always_capture_default_ = value;
        return static_cast<CRTP *>(this);
    }

    // Getters

    /// Get the group of this option
    CLI11_NODISCARD const std::string &get_group() const { return group_; }

    /// True if this is a required option
    CLI11_NODISCARD bool get_required() const { return required_; }

    /// The status of ignore case
    CLI11_NODISCARD bool get_ignore_case() const { return ignore_case_; }

    /// The status of ignore_underscore
    CLI11_NODISCARD bool get_ignore_underscore() const { return ignore_underscore_; }

    /// The status of configurable
    CLI11_NODISCARD bool get_configurable() const { return configurable_; }

    /// The status of configurable
    CLI11_NODISCARD bool get_disable_flag_override() const { return disable_flag_override_; }

    /// Get the current delimiter char
    CLI11_NODISCARD char get_delimiter() const { return delimiter_; }

    /// Return true if this will automatically capture the default value for help printing
    CLI11_NODISCARD bool get_always_capture_default() const { return always_capture_default_; }

    /// The status of the multi option policy
    CLI11_NODISCARD MultiOptionPolicy get_multi_option_policy() const { return multi_option_policy_; }

    // Shortcuts for multi option policy

    /// Set the multi option policy to take last
    CRTP *take_last() {
        auto *self = static_cast<CRTP *>(this);
        self->multi_option_policy(MultiOptionPolicy::TakeLast);
        return self;
    }

    /// Set the multi option policy to take last
    CRTP *take_first() {
        auto *self = static_cast<CRTP *>(this);
        self->multi_option_policy(MultiOptionPolicy::TakeFirst);
        return self;
    }

    /// Set the multi option policy to take all arguments
    CRTP *take_all() {
        auto self = static_cast<CRTP *>(this);
        self->multi_option_policy(MultiOptionPolicy::TakeAll);
        return self;
    }

    /// Set the multi option policy to join
    CRTP *join() {
        auto *self = static_cast<CRTP *>(this);
        self->multi_option_policy(MultiOptionPolicy::Join);
        return self;
    }

    /// Set the multi option policy to join with a specific delimiter
    CRTP *join(char delim) {
        auto self = static_cast<CRTP *>(this);
        self->delimiter_ = delim;
        self->multi_option_policy(MultiOptionPolicy::Join);
        return self;
    }

    /// Allow in a configuration file
    CRTP *configurable(bool value = true) {
        configurable_ = value;
        return static_cast<CRTP *>(this);
    }

    /// Allow in a configuration file
    CRTP *delimiter(char value = '\0') {
        delimiter_ = value;
        return static_cast<CRTP *>(this);
    }
};

/// This is a version of OptionBase that only supports setting values,
/// for defaults. It is stored as the default option in an App.
class OptionDefaults : public OptionBase<OptionDefaults> {
  public:
    OptionDefaults() = default;

    // Methods here need a different implementation if they are Option vs. OptionDefault

    /// Take the last argument if given multiple times
    OptionDefaults *multi_option_policy(MultiOptionPolicy value = MultiOptionPolicy::Throw) {
        multi_option_policy_ = value;
        return this;
    }

    /// Ignore the case of the option name
    OptionDefaults *ignore_case(bool value = true) {
        ignore_case_ = value;
        return this;
    }

    /// Ignore underscores in the option name
    OptionDefaults *ignore_underscore(bool value = true) {
        ignore_underscore_ = value;
        return this;
    }

    /// Disable overriding flag values with an '=<value>' segment
    OptionDefaults *disable_flag_override(bool value = true) {
        disable_flag_override_ = value;
        return this;
    }

    /// set a delimiter character to split up single arguments to treat as multiple inputs
    OptionDefaults *delimiter(char value = '\0') {
        delimiter_ = value;
        return this;
    }
};

class Option : public OptionBase<Option> {
    friend App;

  protected:
    /// @name Names
    ///@{

    /// A list of the short names (`-a`) without the leading dashes
    std::vector<std::string> snames_{};

    /// A list of the long names (`--long`) without the leading dashes
    std::vector<std::string> lnames_{};

    /// A list of the flag names with the appropriate default value, the first part of the pair should be duplicates of
    /// what is in snames or lnames but will trigger a particular response on a flag
    std::vector<std::pair<std::string, std::string>> default_flag_values_{};

    /// a list of flag names with specified default values;
    std::vector<std::string> fnames_{};

    /// A positional name
    std::string pname_{};

    /// If given, check the environment for this option
    std::string envname_{};

    ///@}
    /// @name Help
    ///@{

    /// The description for help strings
    std::string description_{};

    /// A human readable default value, either manually set, captured, or captured by default
    std::string default_str_{};

    /// If given, replace the text that describes the option type and usage in the help text
    std::string option_text_{};

    /// A human readable type value, set when App creates this
    ///
    /// This is a lambda function so "types" can be dynamic, such as when a set prints its contents.
    std::function<std::string()> type_name_{[]() { return std::string(); }};

    /// Run this function to capture a default (ignore if empty)
    std::function<std::string()> default_function_{};

    ///@}
    /// @name Configuration
    ///@{

    /// The number of arguments that make up one option. max is the nominal type size, min is the minimum number of
    /// strings
    int type_size_max_{1};
    /// The minimum number of arguments an option should be expecting
    int type_size_min_{1};

    /// The minimum number of expected values
    int expected_min_{1};
    /// The maximum number of expected values
    int expected_max_{1};

    /// A list of Validators to run on each value parsed
    std::vector<Validator> validators_{};

    /// A list of options that are required with this option
    std::set<Option *> needs_{};

    /// A list of options that are excluded with this option
    std::set<Option *> excludes_{};

    ///@}
    /// @name Other
    ///@{

    /// link back up to the parent App for fallthrough
    App *parent_{nullptr};

    /// Options store a callback to do all the work
    callback_t callback_{};

    ///@}
    /// @name Parsing results
    ///@{

    /// complete Results of parsing
    results_t results_{};
    /// results after reduction
    results_t proc_results_{};
    /// enumeration for the option state machine
    enum class option_state : char {
        parsing = 0,       //!< The option is currently collecting parsed results
        validated = 2,     //!< the results have been validated
        reduced = 4,       //!< a subset of results has been generated
        callback_run = 6,  //!< the callback has been executed
    };
    /// Whether the callback has run (needed for INI parsing)
    option_state current_option_state_{option_state::parsing};
    /// Specify that extra args beyond type_size_max should be allowed
    bool allow_extra_args_{false};
    /// Specify that the option should act like a flag vs regular option
    bool flag_like_{false};
    /// Control option to run the callback to set the default
    bool run_callback_for_default_{false};
    /// flag indicating a separator needs to be injected after each argument call
    bool inject_separator_{false};
    /// flag indicating that the option should trigger the validation and callback chain on each result when loaded
    bool trigger_on_result_{false};
    /// flag indicating that the option should force the callback regardless if any results present
    bool force_callback_{false};
    ///@}

    /// Making an option by hand is not defined, it must be made by the App class
    Option(std::string option_name, std::string option_description, callback_t callback, App *parent)
        : description_(std::move(option_description)), parent_(parent), callback_(std::move(callback)) {
        std::tie(snames_, lnames_, pname_) = detail::get_names(detail::split_names(option_name));
    }

  public:
    /// @name Basic
    ///@{

    Option(const Option &) = delete;
    Option &operator=(const Option &) = delete;

    /// Count the total number of times an option was passed
    CLI11_NODISCARD std::size_t count() const { return results_.size(); }

    /// True if the option was not passed
    CLI11_NODISCARD bool empty() const { return results_.empty(); }

    /// This bool operator returns true if any arguments were passed or the option callback is forced
    explicit operator bool() const { return !empty() || force_callback_; }

    /// Clear the parsed results (mostly for testing)
    void clear() {
        results_.clear();
        current_option_state_ = option_state::parsing;
    }

    ///@}
    /// @name Setting options
    ///@{

    /// Set the number of expected arguments
    Option *expected(int value);

    /// Set the range of expected arguments
    Option *expected(int value_min, int value_max);

    /// Set the value of allow_extra_args which allows extra value arguments on the flag or option to be included
    /// with each instance
    Option *allow_extra_args(bool value = true) {
        allow_extra_args_ = value;
        return this;
    }
    /// Get the current value of allow extra args
    CLI11_NODISCARD bool get_allow_extra_args() const { return allow_extra_args_; }
    /// Set the value of trigger_on_parse which specifies that the option callback should be triggered on every parse
    Option *trigger_on_parse(bool value = true) {
        trigger_on_result_ = value;
        return this;
    }
    /// The status of trigger on parse
    CLI11_NODISCARD bool get_trigger_on_parse() const { return trigger_on_result_; }

    /// Set the value of force_callback
    Option *force_callback(bool value = true) {
        force_callback_ = value;
        return this;
    }
    /// The status of force_callback
    CLI11_NODISCARD bool get_force_callback() const { return force_callback_; }

    /// Set the value of run_callback_for_default which controls whether the callback function should be called to set
    /// the default This is controlled automatically but could be manipulated by the user.
    Option *run_callback_for_default(bool value = true) {
        run_callback_for_default_ = value;
        return this;
    }
    /// Get the current value of run_callback_for_default
    CLI11_NODISCARD bool get_run_callback_for_default() const { return run_callback_for_default_; }

    /// Adds a Validator with a built in type name
    Option *check(Validator validator, const std::string &validator_name = "");

    /// Adds a Validator. Takes a const string& and returns an error message (empty if conversion/check is okay).
    Option *check(std::function<std::string(const std::string &)> Validator,
                  std::string Validator_description = "",
                  std::string Validator_name = "");

    /// Adds a transforming Validator with a built in type name
    Option *transform(Validator Validator, const std::string &Validator_name = "");

    /// Adds a Validator-like function that can change result
    Option *transform(const std::function<std::string(std::string)> &func,
                      std::string transform_description = "",
                      std::string transform_name = "");

    /// Adds a user supplied function to run on each item passed in (communicate though lambda capture)
    Option *each(const std::function<void(std::string)> &func);

    /// Get a named Validator
    Validator *get_validator(const std::string &Validator_name = "");

    /// Get a Validator by index NOTE: this may not be the order of definition
    Validator *get_validator(int index);

    /// Sets required options
    Option *needs(Option *opt) {
        if(opt != this) {
            needs_.insert(opt);
        }
        return this;
    }

    /// Can find a string if needed
    template <typename T = App> Option *needs(std::string opt_name) {
        auto opt = static_cast<T *>(parent_)->get_option_no_throw(opt_name);
        if(opt == nullptr) {
            throw IncorrectConstruction::MissingOption(opt_name);
        }
        return needs(opt);
    }

    /// Any number supported, any mix of string and Opt
    template <typename A, typename B, typename... ARG> Option *needs(A opt, B opt1, ARG... args) {
        needs(opt);
        return needs(opt1, args...);  // NOLINT(readability-suspicious-call-argument)
    }

    /// Remove needs link from an option. Returns true if the option really was in the needs list.
    bool remove_needs(Option *opt);

    /// Sets excluded options
    Option *excludes(Option *opt);

    /// Can find a string if needed
    template <typename T = App> Option *excludes(std::string opt_name) {
        auto opt = static_cast<T *>(parent_)->get_option_no_throw(opt_name);
        if(opt == nullptr) {
            throw IncorrectConstruction::MissingOption(opt_name);
        }
        return excludes(opt);
    }

    /// Any number supported, any mix of string and Opt
    template <typename A, typename B, typename... ARG> Option *excludes(A opt, B opt1, ARG... args) {
        excludes(opt);
        return excludes(opt1, args...);
    }

    /// Remove needs link from an option. Returns true if the option really was in the needs list.
    bool remove_excludes(Option *opt);

    /// Sets environment variable to read if no option given
    Option *envname(std::string name) {
        envname_ = std::move(name);
        return this;
    }

    /// Ignore case
    ///
    /// The template hides the fact that we don't have the definition of App yet.
    /// You are never expected to add an argument to the template here.
    template <typename T = App> Option *ignore_case(bool value = true);

    /// Ignore underscores in the option names
    ///
    /// The template hides the fact that we don't have the definition of App yet.
    /// You are never expected to add an argument to the template here.
    template <typename T = App> Option *ignore_underscore(bool value = true);

    /// Take the last argument if given multiple times (or another policy)
    Option *multi_option_policy(MultiOptionPolicy value = MultiOptionPolicy::Throw);

    /// Disable flag overrides values, e.g. --flag=<value> is not allowed
    Option *disable_flag_override(bool value = true) {
        disable_flag_override_ = value;
        return this;
    }
    ///@}
    /// @name Accessors
    ///@{

    /// The number of arguments the option expects
    CLI11_NODISCARD int get_type_size() const { return type_size_min_; }

    /// The minimum number of arguments the option expects
    CLI11_NODISCARD int get_type_size_min() const { return type_size_min_; }
    /// The maximum number of arguments the option expects
    CLI11_NODISCARD int get_type_size_max() const { return type_size_max_; }

    /// Return the inject_separator flag
    CLI11_NODISCARD bool get_inject_separator() const { return inject_separator_; }

    /// The environment variable associated to this value
    CLI11_NODISCARD std::string get_envname() const { return envname_; }

    /// The set of options needed
    CLI11_NODISCARD std::set<Option *> get_needs() const { return needs_; }

    /// The set of options excluded
    CLI11_NODISCARD std::set<Option *> get_excludes() const { return excludes_; }

    /// The default value (for help printing)
    CLI11_NODISCARD std::string get_default_str() const { return default_str_; }

    /// Get the callback function
    CLI11_NODISCARD callback_t get_callback() const { return callback_; }

    /// Get the long names
    CLI11_NODISCARD const std::vector<std::string> &get_lnames() const { return lnames_; }

    /// Get the short names
    CLI11_NODISCARD const std::vector<std::string> &get_snames() const { return snames_; }

    /// Get the flag names with specified default values
    CLI11_NODISCARD const std::vector<std::string> &get_fnames() const { return fnames_; }
    /// Get a single name for the option, first of lname, pname, sname, envname
    CLI11_NODISCARD const std::string &get_single_name() const {
        if(!lnames_.empty()) {
            return lnames_[0];
        }
        if(!pname_.empty()) {
            return pname_;
        }
        if(!snames_.empty()) {
            return snames_[0];
        }
        return envname_;
    }
    /// The number of times the option expects to be included
    CLI11_NODISCARD int get_expected() const { return expected_min_; }

    /// The number of times the option expects to be included
    CLI11_NODISCARD int get_expected_min() const { return expected_min_; }
    /// The max number of times the option expects to be included
    CLI11_NODISCARD int get_expected_max() const { return expected_max_; }

    /// The total min number of expected  string values to be used