Re: [boost] Re: Preliminary submission: command line & config fil e library

From: Vladimir Prus (ghost_at_[hidden])
Date: 2003-01-20 03:37:44

Thomas Wenisch wrote:
> Hi all,
> 
> I have not followed this discussion closely, but I did want to add on one
> point:
> 
[...]
>>>For example:
>>>
>>>my_program /roll trace file? = "yes"
>>>
>>>CLA is basic facility that is used by many people with different habits. You
>>>could not afford to incur too many restrictions.
> Some programs might support a command line like this:
> 
>    my_program ?
> 
> To print out help information (ie same as my_program --help).  Therefore,
> allowing ? as a command line argument is an important use case.  I am not
> sure whether or not Vladimir's proposal would support a question mark by
> itself.

It does. The question mark is a simple way to tell: "the argument is 
optional". I believe it's extremely usefull and it does not interfere with
having "?" as part of option name, or option value, or argument.

For example, you might take a look at

http://zigzag.cs.msu.su:7813/program_options/html/classboost_1_1program__options_1_1cmdline.html#a3

you can use '?' as value of 'properties' parameter, but no special handling of 
  '?' character in the command line will be done.

Also note that this notation (in context of command line parsing) was not 
invented by me. Instead, it's borrowed from Brad Appleton:

http://www.enteract.com/~bradapp/ftp/src/libs/C++/Options.html

- Volodya