[Boost-bugs] [Boost C++ Libraries] #3330: boost::program_options doesn't allow naming the argument in a straightforward way

Subject: [Boost-bugs] [Boost C++ Libraries] #3330: boost::program_options doesn't allow naming the argument in a straightforward way
From: Boost C++ Libraries (noreply_at_[hidden])
Date: 2009-08-10 13:08:47

#3330: boost::program_options doesn't allow naming the argument in a
straightforward way
------------------------------+---------------------------------------------
 Reporter:  grumbel@…         |       Owner:  vladimir_prus  
     Type:  Feature Requests  |      Status:  new            
Milestone:  Boost 1.40.0      |   Component:  program_options
  Version:  Boost 1.37.0      |    Severity:  Problem        
 Keywords:                    |  
------------------------------+---------------------------------------------
 When using boost::program_options, there is no straightforward way to set
 the name of a boost::program_options::value<>():

 {{{
 #include <iostream>
 #include <boost/program_options.hpp>

 int main()
 {
   boost::program_options::options_description desc;

   desc.add_options()
     ("width", boost::program_options::value<int>(),
      "Give width");

   std::cout << desc << std::endl;

   return 0;
 }
 }}}

 The above code gives:

 {{{
   --width arg           Give width in pixels
 }}}

 What it should allow is replacing the "arg" name with something more
 descriptive like PIXELS:

 {{{
   --width PIXELS           Give width in pixels
 }}}

 For example via {{{boost::program_options::value<int>("PIXELS")}}}.

 Even the tutorial makes "use" of this non-existant feature:

 http://www.boost.org/doc/libs/1_39_0/doc/html/program_options/tutorial.html


 The output at the bottom of the page shows "--optimization n" instead of "
 --optimization arg", same with "path".

 There is a way to accomplish a different arg name by inheriting from
 boost::program_options::typed_value<> as documented at:

 http://stackoverflow.com/questions/1249646/when-using-boostprogramoptions-

 how-does-one-set-the-name-of-the-argument

 But considering that naming the argument is a extremely common use case,
 this should be doable in a much more straightforward manner, such as an
 additional name argument to po_value().

-- 
Ticket URL: <https://svn.boost.org/trac/boost/ticket/3330>
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