Re: [Boost-users] Multiple Multitokens

15 Apr 2009

      Volodya, thanks for the help thus far, I think I am close to getting it to
work.  According to the post you referred me to, multiple of the same
parameter are not collapsed, ie
--list a.txt b.txt --list c.txt d.txt
Should give me access to the two separate lists.

I tried declaring the parameter as usual:
("list", po::value()->multitoken(), "Lists.")

And then I thought it may be the .count property?

cout << "There are " << vm.count("list") << " lists." << endl;

But there is only 1 list.

The idea was to do this:

vector lists;
    for(unsigned int list = 0; list < vm.count("list"); list++)
    {
        vector<string> l = vm["list"].as();
        lists.push_back(l);

        for(unsigned int item = 0; item < lists[list].size(); item++)
            cout << "List: " << list << " Item: " << item << " " <<
lists[list][item] << endl;
    }

Clearly I am still missing the part about accessing the separated "list"
params.  Can you see the problem here?

Thanks,

David
...
David Doria wrote:
...
I want to do something like this:
--NumLists 2 --List0 a.txt b.txt --List1 c.txt d.txt
vector Lists(2);
po::options_description desc("Allowed options");
    desc.add_options()
            ("help", "produce help message")
            ("List0", po::valuemultitoken(),
"List0.")
            ("List1", po::valuemultitoken(),
"List1.")
            ;
But if I wanted to handle --NumLists 10, I would have to manually add
List0,
List1, ... List10 as parameters. That seems a bit silly, but maybe this
is a
very odd usage?
Well, it's somewhat odd :-)
...
Please let me know if you can think of a better way to
handle this.
Well, as a remark, your command line interface will make users cry:
- Do you really want users to type uppercase letters? (Use can use
 case-insensitive mode, of course, and allow any spelling, but upper
 case in your example seems strange.
- Do you really want users to count lists and pass 0, 1, 2, etc explicitly?
- Why do you need explicit specification of the number of lists?
I'd use:
--list a.txt b.txt --list c.txt d.txt
You might find the recent thread useful for handling such command lines:
http://permalink.gmane.org/gmane.comp.lib.boost.user/46405
- Volodya