comparison DEPENDENCIES/generic/include/boost/spirit/home/classic/dynamic/impl/conditions.ipp @ 16:2665513ce2d3

Add boost headers

+/*=============================================================================
+    Copyright (c) 2002-2003 Martin Wille
+    http://spirit.sourceforge.net/
+
+    Use, modification and distribution is subject to 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)
+=============================================================================*/
+#ifndef BOOST_SPIRIT_CONDITIONS_IPP
+#define BOOST_SPIRIT_CONDITIONS_IPP
+
+///////////////////////////////////////////////////////////////////////////////
+#include <boost/spirit/home/classic/meta/parser_traits.hpp>
+#include <boost/spirit/home/classic/core/composite/epsilon.hpp>
+
+///////////////////////////////////////////////////////////////////////////////
+namespace boost { namespace spirit {
+
+BOOST_SPIRIT_CLASSIC_NAMESPACE_BEGIN
+
+    namespace impl {
+
+///////////////////////////////////////////////////////////////////////////////
+//
+// condition evaluation
+//
+///////////////////////////////////////////////////////////////////////////////
+    //////////////////////////////////
+    // condition_parser_selector, decides which parser to use for a condition
+    // If the template argument is a parser then that parser is used.
+    // If the template argument is a functor then a condition parser using
+    // the functor is chosen
+
+    template <typename T> struct embed_t_accessor
+    {
+        typedef typename T::embed_t type;
+    };
+
+#if defined(BOOST_MSVC) && BOOST_MSVC <= 1300
+    template <> struct embed_t_accessor<int>
+    {
+        typedef int type;
+    };
+#endif
+
+    template <typename ConditionT>
+    struct condition_parser_selector
+    {
+        typedef
+            typename mpl::if_<
+                    is_parser<ConditionT>,
+                    ConditionT,
+                    condition_parser<ConditionT>
+                >::type
+            type;
+
+        typedef typename embed_t_accessor<type>::type embed_t;
+    };
+
+    //////////////////////////////////
+    // condition_evaluator, uses a parser to check wether a condition is met
+    // takes a parser or a functor that can be evaluated in boolean context
+    // as template parameter.
+
+    // JDG 4-15-03 refactored
+    template <typename ConditionT>
+    struct condition_evaluator
+    {
+        typedef condition_parser_selector<ConditionT>       selector_t;
+        typedef typename selector_t::type                   selected_t;
+        typedef typename selector_t::embed_t                cond_embed_t;
+
+        typedef typename boost::call_traits<cond_embed_t>::param_type
+            param_t;
+
+        condition_evaluator(param_t s) : cond(s) {}
+
+        /////////////////////////////
+        // evaluate, checks wether condition is met
+        // returns length of a match or a negative number for no-match
+        template <typename ScannerT>
+        std::ptrdiff_t
+        evaluate(ScannerT const &scan) const
+        {
+            typedef typename ScannerT::iterator_t iterator_t;
+            typedef typename parser_result<selected_t, ScannerT>::type cres_t;
+            iterator_t save(scan.first);
+            cres_t result = cond.parse(scan);
+            if (!result)            // reset the position if evaluation
+                scan.first = save;  // fails.
+            return result.length();
+        }
+
+        cond_embed_t cond;
+    };
+
+///////////////////////////////////////////////////////////////////////////////
+    } // namespace impl
+
+BOOST_SPIRIT_CLASSIC_NAMESPACE_END
+
+}} // namespace boost::spirit
+
+#endif