spirit/example/qi/custom_string.cpp
Mateusz Łoskot 0d4d2c1f6c Improve QString integration in custom_string.cpp
Improve QString integration in custom_string.cpp
There is an example of how to use Qi with Qt's QString as a custom string.
This is very helpful but it doesn't work in conjunction with the debug facilities.
The following patch fixes this by adding a couple of template specialisations.

Patch originally submitted as https://svn.boost.org/trac/boost/ticket/8846
2014-12-15 11:53:13 +01:00

114 lines
3.4 KiB
C++

// Copyright (c) 2001-2010 Hartmut Kaiser
//
// Distributed under the Boost Software License, Version 1.0. (See accompanying
// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
// This example demonstrates the steps needed to integrate a custom container
// type to be usable with Spirit.Qi. It shows how to utilize the QString data
// type as a Qi attribute.
// Note: you need to have Qt4 installed on your system and you have to make
// sure your compiler finds the includes and your linker finds the
// proper libraries.
#include <boost/config/warning_disable.hpp>
#include <boost/spirit/include/qi.hpp>
#include <Qt/qstring.h>
namespace boost { namespace spirit { namespace traits
{
// Make Qi recognize QString as a container
template <> struct is_container<QString> : mpl::true_ {};
// Expose the container's (QString's) value_type
template <> struct container_value<QString> : mpl::identity<QChar> {};
// Define how to insert a new element at the end of the container (QString)
template <>
struct push_back_container<QString, QChar>
{
static bool call(QString& c, QChar const& val)
{
c.append(val);
return true;
}
};
// Test if a QString is empty (required for debug)
template <>
struct is_empty_container<QString>
{
static bool call(QString const& c)
{
return c.isEmpty();
}
};
// Define how to stream a QString (required for debug)
template <typename Out, typename Enable>
struct print_attribute_debug<Out, QString, Enable>
{
static void call(Out& out, QString const& val)
{
out << val.toStdString();
}
};
}}}
///////////////////////////////////////////////////////////////////////////////
namespace client
{
template <typename Iterator>
bool parse_qstring(Iterator first, Iterator last, QString& t)
{
using boost::spirit::qi::char_;
using boost::spirit::ascii::space;
using boost::spirit::qi::phrase_parse;
bool r = phrase_parse(first, last, +char_, space, t);
if (!r || first != last) // fail if we did not get a full match
return false;
return r;
}
}
///////////////////////////////////////////////////////////////////////////////
int main()
{
std::cout << "/////////////////////////////////////////////////////////\n\n";
std::cout << "\t\tParsing into a QString from Spirit...\n\n";
std::cout << "/////////////////////////////////////////////////////////\n\n";
std::cout << "Give me a complex number of the form r or (r) or (r,i) \n";
std::cout << "Type [q or Q] to quit\n\n";
std::string str;
while (getline(std::cin, str))
{
if (str.empty() || str[0] == 'q' || str[0] == 'Q')
break;
QString t;
if (client::parse_qstring(str.begin(), str.end(), t))
{
std::cout << "-------------------------\n";
std::cout << "Parsing succeeded\n";
std::cout << "got: " << t.toStdString() << std::endl;
std::cout << "\n-------------------------\n";
}
else
{
std::cout << "-------------------------\n";
std::cout << "Parsing failed\n";
std::cout << "-------------------------\n";
}
}
std::cout << "Bye... :-) \n\n";
return 0;
}