Re: [Boost-bugs] [Boost C++ Libraries] #3703: Request for ability to specify description column width

Subject: Re: [Boost-bugs] [Boost C++ Libraries] #3703: Request for ability to specify description column width
From: Boost C++ Libraries (noreply_at_[hidden])
Date: 2009-12-03 10:05:49

#3703: Request for ability to specify description column width
-------------------------------+--------------------------------------------
  Reporter:  Chard             |       Owner:  s_ochsenknecht               
      Type:  Feature Requests  |      Status:  closed                       
 Milestone:  Boost 1.42.0      |   Component:  program_options              
   Version:  Boost 1.41.0      |    Severity:  Cosmetic                     
Resolution:  fixed             |    Keywords:  description column formatting
-------------------------------+--------------------------------------------

Comment(by Chard <boost@…>):

 Hi Sascha

 I've had a bit more of a look at the changes, and there's a couple of
 points to note:

 1. I had called the original description length variable:
 {{{min_description_length}}}, this has been renamed to
 {{{description_length}}}.  The "{{{min_}}}" part does add some semantic
 meaning to the usage because the length that is specified is not an
 absolute.

 For example, if the user specifies 10 as the description length, he may be
 expecting the description column to occupy ''exactly'' 10 spaces.  But the
 available distance is still determined by the length of the option column,
 as demonstrated by this test case:

 {{{
     {
         options_description desc("",
 options_description::m_default_line_length,
                                  10U);
         desc.add_options()
             ("lt-23-chars", new untyped_value(),
             "this shows that more space is given to the description column
 when possible")
         ;
         stringstream ss;
         ss << desc;
         BOOST_CHECK_EQUAL(ss.str(),
        //123456789_123456789_1234
         "  --lt-23-chars arg     this shows that more space is given to
 the description \n"
         "                        column when possible\n");
     }
 }}}

 2. By tying the default argument for the description length to
 {{{(default_line_length / 2)}}} it does mean that existing code that
 specifies the {{{line_length}}} argument will still compile, but with a
 potentially different display.  The minimum description width will still
 be 40, regardless of the specified {{{line_length}}}.  However, I suspect
 this is a minor point because for most cases the output should look
 ''better''.

 Regards,
 Chard.

-- 
Ticket URL: <https://svn.boost.org/trac/boost/ticket/3703#comment:9>
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