Re: [Boost-users] Boost PropertyTree: read_json() followed by write_xml() produces invalid XML

Subject: Re: [Boost-users] Boost PropertyTree: read_json() followed by write_xml() produces invalid XML
From: Marcel Loose (loose_at_[hidden])
Date: 2014-05-07 03:30:45

Sorry, this post was supposed to go to the developers list. Must have
clicked the wrong link :(

On 05/05/14 23:38, Marcel Loose wrote:
> Hi all,
>
> Last week I posted the message below to the Boost Users group. One of the posters suggested that I stumbled upon a bug in Boost.PropertyTree. 
> So, the question is: am I doing something wrong, or is this is a bug in Boost.PropertyTree?
>
> Best regards,
> Marcel Loose.
>
>
> ---- Start of message ----
>
> I was quite surprised and disappointed to find out that I was unable
> to convert a simple JSON file into XML, using the Boost PropertyTree.
> As input I used the example JSON file from the documentation (see
> example.json below).
>
> I wrote a small program (see example.cc below) that reads in this JSON
> file, writes it to disk as XML file, and finally tries to read back
> this XML file. This last operation fails with an exception (see output
> below); the XML file that is produced (see example.xml below) is
> invalid, because it contains empty tags (<>).
>
> Am I doing something wrong?
>
> Best regards,
> Marcel Loose.
>
>
> $ cat example.json
> {
>    "menu":
>    {
>       "foo": true,
>       "bar": "true",
>       "value": 102.3E+06,
>       "popup":
>       [
>          {"value": "New", "onclick": "CreateNewDoc()"},
>          {"value": "Open", "onclick": "OpenDoc()"}
>       ]
>    }
> }
>
> $ cat example.cc
> #include <boost/property_tree/ptree.hpp>
> #include <boost/property_tree/json_parser.hpp>
> #include <boost/property_tree/xml_parser.hpp>
> #include <fstream>
>
> using namespace std;
> using namespace boost::property_tree;
>
> int main()
> {
>   ptree pt;
>   {
>     read_json("example.json", pt);
>     ofstream ofs("example.xml");
>     write_xml(ofs, pt, xml_writer_make_settings(' ', 2));
>   }
>   {
>     ifstream ifs("example.xml");
>     read_xml(ifs, pt);
>   }
>   return 0;
> }
>
> $ ./example 
> terminate called after throwing an instance of 'boost::exception_detail::clone_impl<boost::exception_detail::error_info_injector<boost::property_tree::xml_parser::xml_parser_error> >'
>   what():  <unspecified file>(7): expected element name
> Aborted
>
> $ cat example.xml
> <?xml version="1.0" encoding="utf-8"?>
> <menu>
>   <foo>true</foo>
>   <bar>true</bar>
>   <value>102.3E+06</value>
>   <popup>
>     <>
>       <value>New</value>
>       <onclick>CreateNewDoc()</onclick>
>     </>
>     <>
>       <value>Open</value>
>       <onclick>OpenDoc()</onclick>
>     </>
>   </popup>
> </menu>
>
> ---- End of message ----