Re: [Boost-users] [program options] vectro from config file

Subject: Re: [Boost-users] [program options] vectro from config file
From: Vladimir Prus (vladimir_at_[hidden])
Date: 2009-07-14 03:03:54

Diederick C. Niehorster wrote:

> Hi Volodya,
> 
> Thank you for your reply. I have placed my code, improved, into the
> validate() function now (see below). Thats a good idea anyway, this
> way it works on input from any source. I am still stuck with the issue
> of how to test whether users specified a vector or not as return
> target in their options_description, that is:
> ("Tex.GaussSigma", po::value<float>(&fTexGaussSigma)  , "Tex.GaussSigma") or
> ("Tex.Color"           , po::value<vector<float>>(&vfTexColor), "Expt.Color")
> 
> Due to the very complicated flow (if you've just looked at the code
> for a few hours) I find it hard to figure out. I suppose i have to run
> typeid(*something*).name() to get the type of some variable and then
> check if its a vector or not. But what should be in the place of
> *something*?

I think you are changing the validate overload that is for vectors, not?
It won't ever be called for non-vectors. 

> As a general point, do you think this would be a good addition to the
> parser, that is, would you want to incorporate this kind of extention
> into the Boost release? It is a much easier way of specifying a
> vector, whether on the command line or from another source without
> having to resort to positional options, which are not a good solution
> for every source and situation. Compare (for command line) [--test "(1
> 2)"] with [--test 1 --test 2].

I am not yet sure this is good addition. In any case, it would be better to
first allow to specify custom validate function for a given option.

> Lastly, in an old post (cant find it now, was 2005 or 2006) a user
> asked whether it was possible to do
> po::parse_config_file(InitFileName,poInit,true); instead of
> po::parse_config_file(ifs,poInit,true);
> as the documentation apparently reflected this at that point. You
> replied that you'd fix that at that time (I believe it was you,
> doesn't really matter), but when i just tried it didnt work. Have you
> decided against it?

I honestly don't remember. If you care about this change, please file a bug
at svn.boost.org, so that it's not forgotted for another 4 years.

- Volodya