概述

命令行参数解析，在写一些命令行的程序时需要用到，args.hxx类似于Python的argparse，但在C++中，它具有静态类型检查，并且速度更快（也允许完全嵌套的组逻辑，而Python的argparse没有），支持自定义类型解析，子命令等。使用上，只需要在工程中include “args.hxx” 就可以正常使用，符合C++11规范，兼容性更好。

文档和源码

API文档地址：

源码地址： at

范例

以下的所有代码示例都将是完整的代码示例，并带有一些输出。

简单范例

#include <iostream>#include <args.hxx>int main(int argc, char **argv){    args::ArgumentParser parser("This is a test program.", "This goes after the options.");    args::HelpFlag help(parser, "help", "Display this help menu", {'h', "help"});    args::CompletionFlag completion(parser, {"complete"});    try    {        parser.ParseCLI(argc, argv);    }    catch (const args::Completion& e)    {        std::cout << e.what();        return 0;    }    catch (const args::Help&)    {        std::cout << parser;        return 0;    }    catch (const args::ParseError& e)    {        std::cerr << e.what() << std::endl;        std::cerr << parser;        return 1;    }    return 0;}

运行输出：

 % ./test % ./test -h  ./test {OPTIONS}     This is a test program.   OPTIONS:      -h, --help         Display this help menu     This goes after the options.  % 

#include <iostream>#include <args.hxx>int main(int argc, char **argv){    args::ArgumentParser parser("This is a test program.", "This goes after the options.");    args::Group group(parser, "This group is all exclusive:", args::Group::Validators::Xor);    args::Flag foo(group, "foo", "The foo flag", {'f', "foo"});    args::Flag bar(group, "bar", "The bar flag", {'b'});    args::Flag baz(group, "baz", "The baz flag", {"baz"});    try    {        parser.ParseCLI(argc, argv);    }    catch (args::Help)    {        std::cout << parser;        return 0;    }    catch (args::ParseError e)    {        std::cerr << e.what() << std::endl;        std::cerr << parser;        return 1;    }    catch (args::ValidationError e)    {        std::cerr << e.what() << std::endl;        std::cerr << parser;        return 1;    }    if (foo) { std::cout << "foo" << std::endl; }    if (bar) { std::cout << "bar" << std::endl; }    if (baz) { std::cout << "baz" << std::endl; }    return 0;}

运行输出：

 % ./test   Group validation failed somewhere!  ./test {OPTIONS}     This is a test program.   OPTIONS:                         This group is all exclusive:        -f, --foo          The foo flag         -b                 The bar flag         --baz              The baz flag     This goes after the options.  % ./test -ffoo % ./test --foofoo % ./test --foo -ffoo % ./test -b      bar % ./test --bazbaz % ./test --baz -fGroup validation failed somewhere!  ./test {OPTIONS}     This is a test program. ... % ./test --baz -fbGroup validation failed somewhere!  ./test {OPTIONS} ... % 

#include <iostream>#include <args.hxx>int main(int argc, char **argv){    args::ArgumentParser parser("This is a test program.", "This goes after the options.");    args::HelpFlag help(parser, "help", "Display this help menu", {'h', "help"});    args::ValueFlag<int> integer(parser, "integer", "The integer flag", {'i'});    args::ValueFlagList<char> characters(parser, "characters", "The character flag", {'c'});    args::Positional<std::string> foo(parser, "foo", "The foo position");    args::PositionalList<double> numbers(parser, "numbers", "The numbers position list");    try    {        parser.ParseCLI(argc, argv);    }    catch (args::Help)    {        std::cout << parser;        return 0;    }    catch (args::ParseError e)    {        std::cerr << e.what() << std::endl;        std::cerr << parser;        return 1;    }    catch (args::ValidationError e)    {        std::cerr << e.what() << std::endl;        std::cerr << parser;        return 1;    }    if (integer) { std::cout << "i: " << args::get(integer) << std::endl; }    if (characters) { for (const auto ch: args::get(characters)) { std::cout << "c: " << ch << std::endl; } }    if (foo) { std::cout << "f: " << args::get(foo) << std::endl; }    if (numbers) { for (const auto nm: args::get(numbers)) { std::cout << "n: " << nm << std::endl; } }    return 0;}

运行输出：

% ./test -h  ./test {OPTIONS} [foo] [numbers...]     This is a test program.   OPTIONS:      -h, --help         Display this help menu       -i integer         The integer flag       -c characters      The character flag       foo                The foo position       numbers            The numbers position list       "--" can be used to terminate flag options and force all following      arguments to be treated as positional options     This goes after the options.  % ./test -i 5i: 5 % ./test -i 5.2Argument 'integer' received invalid value type '5.2'  ./test {OPTIONS} [foo] [numbers...]  % ./test -c 1 -c 2 -c 3c: 1c: 2c: 3 %  % ./test 1 2 3 4 5 6 7 8 9f: 1n: 2n: 3n: 4n: 5n: 6n: 7n: 8n: 9 % ./test 1 2 3 4 5 6 7 8 9 aArgument 'numbers' received invalid value type 'a'  ./test {OPTIONS} [foo] [numbers...]     This is a test program. ...

#include <iostream>#include <args.hxx>int main(int argc, char **argv){    args::ArgumentParser p("git-like parser");    args::Group commands(p, "commands");    args::Command add(commands, "add", "add file contents to the index");    args::Command commit(commands, "commit", "record changes to the repository");    args::Group arguments(p, "arguments", args::Group::Validators::DontCare, args::Options::Global);    args::ValueFlag<std::string> gitdir(arguments, "path", "", {"git-dir"});    args::HelpFlag h(arguments, "help", "help", {'h', "help"});    args::PositionalList<std::string> pathsList(arguments, "paths", "files to commit");    try    {        p.ParseCLI(argc, argv);        if (add)        {            std::cout << "Add";        }        else        {            std::cout << "Commit";        }        for (auto &&path : pathsList)        {            std::cout << ' ' << path;        }        std::cout << std::endl;    }    catch (args::Help)    {        std::cout << p;    }    catch (args::Error& e)    {        std::cerr << e.what() << std::endl << p;        return 1;    }    return 0;}

运行输出：

% ./test -h  ./test COMMAND [paths...] {OPTIONS}    git-like parser  OPTIONS:      commands        add                               add file contents to the index        commit                            record changes to the repository      arguments        --git-dir=[path]        -h, --help                        help        paths...                          files      "--" can be used to terminate flag options and force all following      arguments to be treated as positional options% ./test add 1 2Add 1 2

#include <iostream>#include "args.hxx"args::Group arguments("arguments");args::ValueFlag<std::string> gitdir(arguments, "path", "", {"git-dir"});args::HelpFlag h(arguments, "help", "help", {'h', "help"});args::PositionalList<std::string> pathsList(arguments, "paths", "files to commit");void CommitCommand(args::Subparser &parser){    args::ValueFlag<std::string> message(parser, "MESSAGE", "commit message", {'m'});    parser.Parse();    std::cout << "Commit";    for (auto &&path : pathsList)    {        std::cout << ' ' << path;    }    std::cout << std::endl;    if (message)    {        std::cout << "message: " << args::get(message) << std::endl;    }}int main(int argc, const char **argv){    args::ArgumentParser p("git-like parser");    args::Group commands(p, "commands");    args::Command add(commands, "add", "add file contents to the index", [&](args::Subparser &parser)    {        parser.Parse();        std::cout << "Add";        for (auto &&path : pathsList)        {            std::cout << ' ' << path;        }        std::cout << std::endl;    });    args::Command commit(commands, "commit", "record changes to the repository", &CommitCommand);    args::GlobalOptions globals(p, arguments);    try    {        p.ParseCLI(argc, argv);    }    catch (args::Help)    {        std::cout << p;    }    catch (args::Error& e)    {        std::cerr << e.what() << std::endl << p;        return 1;    }    return 0;}

运行结果：

% ./test -h  ./test COMMAND [paths...] {OPTIONS}    git-like parser  OPTIONS:      commands        add                               add file contents to the index        commit                            record changes to the repository      arguments        --git-dir=[path]        -h, --help                        help        paths...                          files      "--" can be used to terminate flag options and force all following      arguments to be treated as positional options% ./test add 1 2Add 1 2% ./test commit -m "my commit message" 1 2Commit 1 2message: my commit message

这里我们使用std::tuple

#include <iostream>#include <tuple>std::istream& operator>>(std::istream& is, std::tuple<int, int>& ints){    is >> std::get<0>(ints);    is.get();    is >> std::get<1>(ints);    return is;}#include <args.hxx>struct DoublesReader{    void operator()(const std::string &name, const std::string &value, std::tuple<double, double> &destination)    {        size_t commapos = 0;        std::get<0>(destination) = std::stod(value, &commapos);        std::get<1>(destination) = std::stod(std::string(value, commapos + 1));    }};int main(int argc, char **argv){    args::ArgumentParser parser("This is a test program.");    args::Positional<std::tuple<int, int>> ints(parser, "INTS", "This takes a pair of integers.");    args::Positional<std::tuple<double, double>, DoublesReader> doubles(parser, "DOUBLES", "This takes a pair of doubles.");    try    {        parser.ParseCLI(argc, argv);    }    catch (args::Help)    {        std::cout << parser;        return 0;    }    catch (args::ParseError e)    {        std::cerr << e.what() << std::endl;        std::cerr << parser;        return 1;    }    if (ints)    {        std::cout << "ints found: " << std::get<0>(args::get(ints)) << " and " << std::get<1>(args::get(ints)) << std::endl;    }    if (doubles)    {        std::cout << "doubles found: " << std::get<0>(args::get(doubles)) << " and " << std::get<1>(args::get(doubles)) << std::endl;    }    return 0;}

运行输出：

 % ./test -hArgument could not be matched: 'h'  ./test [INTS] [DOUBLES]     This is a test program.   OPTIONS:      INTS               This takes a pair of integers.       DOUBLES            This takes a pair of doubles.  % ./test 5ints found: 5 and 0 % ./test 5,8ints found: 5 and 8 % ./test 5,8 2.4,8ints found: 5 and 8doubles found: 2.4 and 8 % ./test 5,8 2.4, terminate called after throwing an instance of 'std::invalid_argument'  what():  stodzsh: abort      ./test 5,8 2.4, % ./test 5,8 2.4 terminate called after throwing an instance of 'std::out_of_range'  what():  basic_string::basic_string: __pos (which is 4) > this->size() (which is 3)zsh: abort      ./test 5,8 2.4 % ./test 5,8 2.4-7ints found: 5 and 8doubles found: 2.4 and 7 % ./test 5,8 2.4,-7ints found: 5 and 8doubles found: 2.4 and -7

更多范例请参考github上的手册：