[Boost-commit] svn:boost r59583 - trunk/libs/spirit/example/qi

Subject: [Boost-commit] svn:boost r59583 - trunk/libs/spirit/example/qi
From: hartmut.kaiser_at_[hidden]
Date: 2010-02-08 11:09:38

Author: hkaiser
Date: 2010-02-08 11:09:37 EST (Mon, 08 Feb 2010)
New Revision: 59583
URL: http://svn.boost.org/trac/boost/changeset/59583

Log:
Spirit: Adding new example
Added:
   trunk/libs/spirit/example/qi/adapt_template_struct.cpp   (contents, props changed)

Added: trunk/libs/spirit/example/qi/adapt_template_struct.cpp
==============================================================================
--- (empty file)
+++ trunk/libs/spirit/example/qi/adapt_template_struct.cpp	2010-02-08 11:09:37 EST (Mon, 08 Feb 2010)
@@ -0,0 +1,92 @@
+//  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 a trick allowing to adapt a template data 
+//  structure as a Fusion sequence in order to use is for direct attribute
+//  propagation. See http://boost-spirit.com/home/ 
+//  for more information.
+
+#include <boost/spirit/include/qi.hpp>
+
+namespace qi = boost::spirit::qi;
+namespace fusion = boost::fusion;
+
+namespace client
+{
+    template <typename A, typename B>
+    struct data
+    {
+        A a;
+        B b;
+    };
+
+    template <typename Iterator, typename A, typename B>
+    struct data_grammar : qi::grammar<Iterator, data<A, B>()>
+    {
+        data_grammar() : data_grammar::base_type(start) 
+        {
+            start = real_start;
+            real_start = qi::auto_ >> ',' >> qi::auto_;
+        }
+
+        qi::rule<Iterator, data<A, B>()> start;
+        qi::rule<Iterator, fusion::vector<A&, B&>()> real_start;
+    };
+}
+
+namespace boost { namespace spirit { namespace traits 
+{
+    template <typename A, typename B>
+    struct transform_attribute<client::data<A, B>, fusion::vector<A&, B&> >
+    {
+        typedef fusion::vector<A&, B&> type;
+
+        static type pre(client::data<A, B>& val) { return type(val.a, val.b); }
+        static void post(client::data<A, B>&, fusion::vector<A&, B&> const&) {}
+        static void fail(client::data<A, B>&) {}
+    };
+}}}
+
+///////////////////////////////////////////////////////////////////////////////
+int main()
+{
+    std::cout << "/////////////////////////////////////////////////////////\n\n";
+    std::cout << "\t\tA parser for Spirit utilizing an adapted template ...\n\n";
+    std::cout << "/////////////////////////////////////////////////////////\n\n";
+
+    std::cout << "Give me two comma separated integers:\n";
+    std::cout << "Type [q or Q] to quit\n\n";
+
+    std::string str;
+    client::data_grammar<std::string::const_iterator, long, int> g; // Our grammar
+    while (getline(std::cin, str))
+    {
+        if (str.empty() || str[0] == 'q' || str[0] == 'Q')
+            break;
+
+        client::data<long, int> d;
+        std::string::const_iterator iter = str.begin();
+        std::string::const_iterator end = str.end();
+        bool r = phrase_parse(iter, end, g, qi::space, d);
+
+        if (r && iter == end)
+        {
+            std::cout << "-------------------------\n";
+            std::cout << "Parsing succeeded\n";
+            std::cout << "got: " << d.a << "," << d.b << std::endl;
+            std::cout << "\n-------------------------\n";
+        }
+        else
+        {
+            std::cout << "-------------------------\n";
+            std::cout << "Parsing failed\n";
+            std::cout << "-------------------------\n";
+        }
+    }
+
+    return 0;
+}
+
+