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

Subject: Re: [Boost-users] [program options] vectro from config file
From: Diederick C. Niehorster (dcnieho_at_[hidden])
Date: 2009-07-14 00:53:08

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*?

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].

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?

Best,
Diederick

-----
Index: detail/value_semantic.hpp
===================================================================
--- detail/value_semantic.hpp   (revision 54915)
+++ detail/value_semantic.hpp   (working copy)
@@ -8,6 +8,8 @@

 #include <boost/throw_exception.hpp>

+#include <boost/algorithm/string.hpp>
+
 namespace boost { namespace program_options {

     extern BOOST_PROGRAM_OPTIONS_DECL std::string arg;
@@ -142,11 +144,28 @@
                 /* We call validate so that if user provided
                    a validator for class T, we use it even
                    when parsing vector<T>.  */
-                boost::any a;
-                std::vector<std::basic_string<charT> > v;
-                v.push_back(s[i]);
-                validate(a, v, (T*)0, 0);
-                tv->push_back(boost::any_cast<T>(a));
+
+                vector<std::basic_string<charT>> value;
+
+                // test if vector notation is used in input
+                if (*s[i].begin() == '(' && *s[i].rbegin() == ')')
+                {
+                    // TODO: test if vector is expected by user, if not, no spl
itting
+                    // TODO: if vector expected, test if its vector of strings,
 that will need special treatment
+                    split( value, s[i].substr(1, s[i].size()-2), is_any_of(" ")
 );
+                }
+                else
+                    value.push_back(s[i]);
+
+                // validate option values
+                for (unsigned j = 0; j < value.size(); j++)
+                {
+                    boost::any a;
+                    std::vector<std::basic_string<charT> > v;
+                    v.push_back(value[j]);
+                    validate(a, v, (T*)0, 0);
+                    tv->push_back(boost::any_cast<T>(a));
+                }
             }
             catch(const bad_lexical_cast& /*e*/) {
                 boost::throw_exception(invalid_option_value(s[i]));