This is in continuation of my question mentioned here
Inconsistent Generator directive column behavior in boost karma
I want to wrap that rule into another rule and when doing so , pass the column directive to the child rule but I cannot figure out what's the right way of doing that.
Here is the code below
#include <boost/spirit/include/karma.hpp>
#include <boost/fusion/include/struct.hpp>
#include <boost/fusion/include/nview.hpp>
///////////////////////////////////////////////////////////////////////////////
namespace client
{
struct BoxData
{
int num;
std::string datatype;
std::string dataname;
std::string inputicon;
};
struct Box
{
std::vector<BoxData> box_data;
};
typedef std::back_insert_iterator<std::string> iterator_type;
}
BOOST_FUSION_ADAPT_STRUCT(
client::BoxData,
// (int, num)
(std::string, datatype)
(std::string, dataname)
(std::string, inputicon)
)
BOOST_FUSION_ADAPT_STRUCT(
client::Box,
(std::vector<client::BoxData>, box_data)
)
///////////////////////////////////////////////////////////////////////////////
int main()
{
// some employees
std::vector<client::BoxData> const employees{
{25, "int", "sra_command", "fa fa-wrench"},
{26, "float", "swt_command", "fa fa-wrench"},
{27, "double", "msc_command", "fa fa-mobile"},
{28, "int", "sra_command", "fa fa-wrench"},
{29, "float", "swt_command", "fa fa-wrench"},
{30, "double", "msc_command", "fa fa-mobile"},
{31, "int", "sra_command", "fa fa-wrench"},
{32, "float", "swt_command", "fa fa-wrench"},
{33, "double", "msc_command", "fa fa-mobile"},
};
client::Box box;
///TODO prevent copying of the vector
box.box_data = employees;
// now print them all
std::string generated;
{
using namespace boost::spirit::karma;
using Sink = client::iterator_type;
using BoxDataAttr = client::BoxData;
using BoxAttr = client::Box;
rule<Sink, BoxDataAttr(),space_type> small_box = "<B>" << string << "<1>" << string << "<2>" << string << "<3>";
rule<Sink , BoxAttr()> big_box = "<Start>" << *small_box << "<End>" ;
generate(Sink(generated),[big_box],box);
}
std::cout << generated << std::endl;
}
In the line
rule<Sink , BoxAttr()> big_box = "<Start>" << *small_box << "<End>" ;
I want to pass the
columns(2, "delimiter\n")[small_box]
delimiter so that the column delimiter is applied to the small_box rule.
So the expected output becomes
<Start><B>int<1>sra_command<2>fa fa-wrench<3><B>float<1>swt_command<2>fa fa-wrench<3>delimiter
<B>double<1>msc_command<2>fa fa-mobile<3><B>int<1>sra_command<2>fa fa-wrench<3>delimiter
<B>float<1>swt_command<2>fa fa-wrench<3><B>double<1>msc_command<2>fa fa-mobile<3>delimiter
<B>int<1>sra_command<2>fa fa-wrench<3><B>float<1>swt_command<2>fa fa-wrench<3>delimiter
<B>double<1>msc_command<2>fa fa-mobile<3>delimiter<End>
Eventually since there would be vector which would pass another custom delimiter to the big_box rule.
I am planning to write a diagnostic interface as an exercise for learning various C++ concepts which involves the following.
1.Parsing data from an IDL file .I haven't defined the exact format yet but will look something similar to this
struct Data1
{
int command_one output "fa fa-wrench";
float commmand_two output "fa fa-sensor";
}
struct Data2
{
bool a input switch;
int b input progress_bar {0,100} ;
}
Generating HTML elements from the IDL file. Each struct is wrapped in a box which contains the individual elements inside them in smaller boxes with their icons/optional parts. The nth delimiter is useful for generating the bootstrap grid for placement of these boxes on the screen.
Complete the HTML page with a websocket implementation that updates DOM elements automatically when JSON data is received containing DOM element name -value pair . Similarly for each input , a send command is implemented to wrap it in a JSON and send to the web server.
Auto generate the code for the webserver so that the only code left to implement is receiving/transmitting data from an external source with all conversions to/from JSON generated.
The following use case prompted me to look for a parser/generator solution.
I'm not too sure about the cause for your question, but it seems to me the solution from yesterday holds:
rule<Sink, BoxDataAttr()> small_box = "<B>" << string << "<1>" << string << "<2>" << string << "<3>";
rule<Sink, BoxAttr()> big_box = "<Start>" << columns(4, "delimiter\n") [small_box % eol] << "<End>" ;
generate(Sink(generated), big_box, employees);
Prints
<Start><B>int<1>sra_command<2>fa fa-wrench<3>
<B>float<1>swt_command<2>fa fa-wrench<3>
delimiter
<B>double<1>msc_command<2>fa fa-mobile<3>
<B>int<1>sra_command<2>fa fa-wrench<3>
delimiter
<B>float<1>swt_command<2>fa fa-wrench<3>
<B>double<1>msc_command<2>fa fa-mobile<3>
delimiter
<B>int<1>sra_command<2>fa fa-wrench<3>
<B>float<1>swt_command<2>fa fa-wrench<3>
delimiter
<B>double<1>msc_command<2>fa fa-mobile<3>delimiter
<End>
On a hunch, you might have missed the fact that you had , space_type as the delimiter on the small_box rule.
Eventually since there would be vector which would pass another custom delimiter to the big_box rule.
At this point I question your choice of tools. Why not roll your own pretty-printing here. I expect it to be considerably simpler. Also read up on https://meta.stackexchange.com/questions/66377/what-is-the-xy-problem
Here's avoiding copying the vector:
client::Box const employees { {
{25, "int", "sra_command", "fa fa-wrench"},
{26, "float", "swt_command", "fa fa-wrench"},
{27, "double", "msc_command", "fa fa-mobile"},
{28, "int", "sra_command", "fa fa-wrench"},
{29, "float", "swt_command", "fa fa-wrench"},
{30, "double", "msc_command", "fa fa-mobile"},
{31, "int", "sra_command", "fa fa-wrench"},
{32, "float", "swt_command", "fa fa-wrench"},
{33, "double", "msc_command", "fa fa-mobile"},
} };
More generally, move semantics could have served:
box.box_data = std::move(employees);