From: eric_at_[hidden]
Date: 2008-03-01 14:32:57
Author: eric_niebler
Date: 2008-03-01 14:32:56 EST (Sat, 01 Mar 2008)
New Revision: 43441
URL: http://svn.boost.org/trac/boost/changeset/43441
Log:
add map_assign example
Added:
trunk/libs/xpressive/proto/example/map_assign.cpp (contents, props changed)
Text files modified:
trunk/libs/xpressive/proto/example/Jamfile.v2 | 5 +++++
trunk/libs/xpressive/proto/example/futures.cpp | 2 +-
2 files changed, 6 insertions(+), 1 deletions(-)
Modified: trunk/libs/xpressive/proto/example/Jamfile.v2
==============================================================================
--- trunk/libs/xpressive/proto/example/Jamfile.v2 (original)
+++ trunk/libs/xpressive/proto/example/Jamfile.v2 2008-03-01 14:32:56 EST (Sat, 01 Mar 2008)
@@ -58,3 +58,8 @@
futures.cpp
;
+exe map_assign
+ :
+ map_assign.cpp
+ ;
+
Modified: trunk/libs/xpressive/proto/example/futures.cpp
==============================================================================
--- trunk/libs/xpressive/proto/example/futures.cpp (original)
+++ trunk/libs/xpressive/proto/example/futures.cpp 2008-03-01 14:32:56 EST (Sat, 01 Mar 2008)
@@ -120,7 +120,7 @@
tuple<A, B, C> t1 = (a && b && c).get();
tuple<A, C> t2 = ((a || a) && c).get();
tuple<A, B, C> t3 = ((a && b || a && b) && c).get();
- tuple<tuple<A, B>, C> t4 = (( ab || ab) && c).get();
+ tuple<tuple<A, B>, C> t4 = ((ab || ab) && c).get();
return 0;
}
Added: trunk/libs/xpressive/proto/example/map_assign.cpp
==============================================================================
--- (empty file)
+++ trunk/libs/xpressive/proto/example/map_assign.cpp 2008-03-01 14:32:56 EST (Sat, 01 Mar 2008)
@@ -0,0 +1,105 @@
+//[ MapAssign
+// Copyright 2008 Eric Niebler. 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 is a port of map_list_assign from the Boost.Assign library.
+// It has the advantage of being more efficient at runtime by not
+// building any temporary container that requires dynamic allocation.
+
+#include <map>
+#include <string>
+#include <iostream>
+#include <boost/xpressive/proto/proto.hpp>
+#include <boost/xpressive/proto/transform.hpp>
+
+using namespace boost;
+using namespace proto;
+
+struct map_list_of_tag
+{};
+
+// A simple callable function object that inserts a
+// (key,value) pair into a map.
+struct insert
+ : callable
+{
+ template<typename Sig>
+ struct result;
+
+ template<typename This, typename Map, typename Key, typename Value>
+ struct result<This(Map, Key, Value)>
+ : add_reference<Map>
+ {};
+
+ template<typename Map, typename Key, typename Value>
+ Map &operator()(Map &map, Key const &key, Value const &value) const
+ {
+ map.insert(typename Map::value_type(key, value));
+ return map;
+ }
+};
+
+// The grammmar for valid map-list expressions, and a
+// transform that populates the map.
+struct MapListOf
+ : or_<
+ when<
+ function<terminal<map_list_of_tag>, terminal<_>, terminal<_> >
+ , insert(_visitor, _arg(_arg1), _arg(_arg2))
+ >
+ , when<
+ function<MapListOf, terminal<_>, terminal<_> >
+ , insert(MapListOf(_arg0), _arg(_arg1), _arg(_arg2))
+ >
+ >
+{};
+
+template<typename Expr>
+struct map_list_of_expr;
+
+struct map_list_of_dom
+ : domain<pod_generator<map_list_of_expr>, MapListOf>
+{};
+
+// An expression wrapper that provides a conversion to a
+// map that uses the MapListOf
+template<typename Expr>
+struct map_list_of_expr
+{
+ BOOST_PROTO_EXTENDS(Expr, map_list_of_expr, map_list_of_dom)
+ BOOST_PROTO_EXTENDS_FUNCTION(Expr, map_list_of_expr, map_list_of_dom)
+
+ template<typename Map>
+ operator Map() const
+ {
+ Map map;
+ return MapListOf()(*this, 0, map);
+ }
+};
+
+map_list_of_expr<terminal<map_list_of_tag>::type> const map_list_of = {{{}}};
+
+int main()
+{
+ // Initialize a map:
+ std::map<std::string, int> op =
+ map_list_of
+ ("<",1)
+ ("<=",2)
+ (">",3)
+ (">=",4)
+ ("=",5)
+ ("<>",6)
+ ;
+
+ std::cout << "\"<\" --> " << op["<"] << std::endl;
+ std::cout << "\"<=\" --> " << op["<="] << std::endl;
+ std::cout << "\">\" --> " << op[">"] << std::endl;
+ std::cout << "\">=\" --> " << op[">="] << std::endl;
+ std::cout << "\"=\" --> " << op["="] << std::endl;
+ std::cout << "\"<>\" --> " << op["<>"] << std::endl;
+
+ return 0;
+}
+//]