Subject: [Boost-commit] svn:boost r55389 - trunk/boost/spirit/home/karma/operator
From: hartmut.kaiser_at_[hidden]
Date: 2009-08-03 11:54:03
Author: hkaiser
Date: 2009-08-03 11:54:02 EDT (Mon, 03 Aug 2009)
New Revision: 55389
URL: http://svn.boost.org/trac/boost/changeset/55389
Log:
Spirit: karma optional now can be invoked with incompatible attribute types
Text files modified:
trunk/boost/spirit/home/karma/operator/optional.hpp | 34 +++++++++++++++++++++++++++++-----
1 files changed, 29 insertions(+), 5 deletions(-)
Modified: trunk/boost/spirit/home/karma/operator/optional.hpp
==============================================================================
--- trunk/boost/spirit/home/karma/operator/optional.hpp (original)
+++ trunk/boost/spirit/home/karma/operator/optional.hpp 2009-08-03 11:54:02 EDT (Mon, 03 Aug 2009)
@@ -1,4 +1,4 @@
-// Copyright (c) 2001-2007 Joel de Guzman
+// Copyright (c) 2001-2009 Joel de Guzman
// Copyright (c) 2001-2009 Hartmut Kaiser
//
// Distributed under the Boost Software License, Version 1.0. (See accompanying
@@ -17,6 +17,7 @@
#include <boost/spirit/home/support/info.hpp>
#include <boost/mpl/assert.hpp>
#include <boost/optional.hpp>
+#include <boost/type_traits/is_convertible.hpp>
namespace boost { namespace spirit
{
@@ -34,6 +35,7 @@
{
namespace detail
{
+ ///////////////////////////////////////////////////////////////////////
template <typename Attribute>
inline bool
optional_is_valid(boost::optional<Attribute> const& opt)
@@ -54,6 +56,7 @@
return true;
}
+ ///////////////////////////////////////////////////////////////////////
template <typename Attribute>
inline Attribute const&
optional_get(boost::optional<Attribute> const& opt)
@@ -73,6 +76,25 @@
{
return unused;
}
+
+ ///////////////////////////////////////////////////////////////////////
+ template <
+ typename OutputIterator, typename Context, typename Delimiter
+ , typename Attribute, typename Subject>
+ void generate_optional(OutputIterator& sink, Context& ctx
+ , Delimiter const& d, Attribute const& attr, Subject const& subject
+ , mpl::true_)
+ {
+ if (optional_is_valid(attr))
+ subject.generate(sink, ctx, d, detail::optional_get(attr));
+ }
+
+ template <
+ typename OutputIterator, typename Context, typename Delimiter
+ , typename Attribute, typename Subject>
+ void generate_optional(OutputIterator&, Context&, Delimiter const&
+ , Attribute const&, Subject const&, mpl::false_)
+ {}
}
///////////////////////////////////////////////////////////////////////////
@@ -82,7 +104,7 @@
typedef Subject subject_type;
typedef typename subject_type::properties properties;
- template <typename Context, typename Unused>
+ template <typename Context, typename Unused = unused_type>
struct attribute
{
// Build a boost::optional from the subject's attribute. Note
@@ -104,9 +126,11 @@
bool generate(OutputIterator& sink, Context& ctx
, Delimiter const& d, Attribute const& attr) const
{
- if (detail::optional_is_valid(attr))
- subject.generate(sink, ctx, d, detail::optional_get(attr));
- return detail::sink_is_good(sink);
+ typedef is_convertible<Attribute
+ , typename attribute<Context>::type> predicate;
+
+ detail::generate_optional(sink, ctx, d, attr, subject, predicate());
+ return sink_is_good(sink);
}
template <typename Context>