New subject: [Program Options] terminate parsing after first positional argument

4 Jul 2012

      Hello,

How can I tell Boost Program Options to stop parsing the arguments as soon as it finds a positional argument?

I'd like to be able to parse the argument list "-v chmod -R -v 600 foo" as having one argument for my program (-v) and the rest as a std::vector of std::string (including the -v). 

In the attached program I have tried 2 different approaches. The first uses multitoken with the arguments "--command date -u -v", it fails because "-u" isn't known.

The second uses collect_unrecognized with "chmod -R -v 600", it doesn't work because -v is interpreted by boost and doesn't end up in the vector.

As someone said back in 2005, perhaps I'm trying to write xargs:
http://thread.gmane.org/gmane.comp.lib.boost.user/9529/focus=9641

I know that I can ask my users to write

a.out -v -- chmod -R -v 600 foo

but I don't want to do that. I want them to write "a.out -v chmod -R -v 600 foo". The first positional argument should should tell boost to stop processing.

Another slightly different question. If I have a multitoken option that takes doubles how can I get it to accept negative values? If I give my program "--floats 1 8 -4 6" where --floats starts a multitoken option that accepts double, I get an exception saying that "-4" is an unknown option.

thanks
Stuart

This is what my test program gives me with boost 1.50:

argv: dd --command date -u -v 
unrecognised option '-u'
Allowed options:
  -v [ --verbose ]      verbose
  --command arg         command to run

2nd try
argv: dd chmod -R -v 600 
I'm verbose
v: chmod -R 600 
3rd try
argv: dd --floats 1 8 -4 6 
unrecognised option '-4'
Allowed options:
  -v [ --verbose ]      verbose
  -f [ --floats ] arg   numbers

and my program (formatted to fit in 80 characters)

#include <boost/program_options.hpp>
#include <boost/range/algorithm.hpp>
#include <boost/program_options/parsers.hpp>
#include <boost/program_options/options_description.hpp>
#include <iostream>

namespace po = boost::program_options;
#define nelements(a) (sizeof (a) / sizeof (a)[0])

void print(char const * * b, char const * * e)
{
  std::cout << "argv: ";
  std::copy(b, e, std::ostream_iterator<char const *>(std::cout, " "));
  std::cout << std::endl;
}

int main(int argc, char ** argv)
{
  {
    bool verbose;
    std::vector<std::string> command;

    po::options_description desc("Allowed options");
    desc.add_options()
      ("verbose,v",
        po::bool_switch(&verbose)->default_value(false), "verbose")
      ("command", po::value<std::vector<std::string> >(&command)
        ->multitoken(), "command to run")
      ;

    char const * args[] = { "dd", "--command", "date", "-u", "-v", 0 };
    print(args, args + nelements(args) - 1);

    po::variables_map vm;
    try
    {
      po::store(po::command_line_parser(nelements(args) - 1, args)
        .options(desc).run(), vm);
      po::notify(vm);
      if (verbose)
        std::cout << "I'm verbose\n";
      std::cout << "command: ";
      boost::copy(command,
        std::ostream_iterator<std::string>(std::cout, " "));
      std::cout << std::endl;
    }
    catch (boost::program_options::unknown_option & x)
    {
      std::cerr << x.what() << "\n" << desc << "\n";
    }
  }

  std::cout << "2nd try\n";
  {
    bool verbose;

    po::options_description desc("Allowed options");
    desc.add_options()
      ("verbose,v",
        po::bool_switch(&verbose)->default_value(false), "verbose")
      ;

    char const * args[] = { "dd", "chmod", "-R", "-v", "600", 0 };
    print(args, args + nelements(args) - 1);
    po::variables_map vm;
    po::parsed_options parsed =
      po::command_line_parser(nelements(args) - 1, args).
      options(desc).allow_unregistered().run();
    try
    {
       po::store(parsed, vm);
    }
    catch (boost::program_options::unknown_option & x)
    {
      std::cerr << x.what() << "\n" << desc << "\n";
      exit(2);
    }
    po::notify(vm);
    if (verbose)
      std::cout << "I'm verbose\n";
    std::cout << "v: ";

    std::vector<std::string> v = po::collect_unrecognized(
      parsed.options,
      po::include_positional);
    boost::copy(v, std::ostream_iterator<std::string>(std::cout, " "));
    std::cout << std::endl;
  }

  std::cout << "3rd try\n";
  {
    bool verbose;
    std::vector<double> f;

    po::options_description all("Allowed options");
    all.add_options()
      ("verbose,v",
        po::bool_switch(&verbose)->default_value(false), "verbose")
      ("floats,f",
        po::value<std::vector<double> >(&f)->multitoken(), "numbers")
      ;

    char const * args[] = { "dd", "--floats", "1", "8", "-4", "6", 0 };
    print(args, args + nelements(args) - 1);
    po::variables_map vm;
    try
    {
      po::store(po::command_line_parser(nelements(args) - 1, args)
        .options(all).run(), vm);
      po::notify(vm);
      if (verbose)
        std::cout << "I'm verbose\n";
      std::cout << "floats: ";
      boost::copy(f, std::ostream_iterator<double>(std::cout, " "));
      std::cout << std::endl;
    }
    catch (boost::program_options::unknown_option & x)
    {
      std::cerr << x.what() << "\n" << all << "\n";
    }
  }
}

[Program Options] terminate parsing after first positional argument

Stuart Pook

Evan Driscoll

Vladimir Prus

Evan Driscoll

Evan Driscoll

Evan Driscoll

Evan Driscoll

Vladimir Prus

driscoll＠cs.wisc.edu

driscoll＠cs.wisc.edu

Evan Driscoll

Olaf Meeuwissen

driscoll＠cs.wisc.edu

Stuart Pook

Olaf Meeuwissen

Stuart Pook

sjrd

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