added function output iterator adaptor

[SVN r9351]

fun_out_iter_example.cpp

@@ -0,0 +1,41 @@
+// (C) Copyright Jeremy Siek 2001. Permission to copy, use, modify,
+// sell and distribute this software is granted provided this
+// copyright notice appears in all copies. This software is provided
+// "as is" without express or implied warranty, and with no claim as
+// to its suitability for any purpose.
+
+// Revision History:
+
+// 27 Feb 2001   Jeremy Siek
+//      Initial checkin.
+
+#include <iostream>
+#include <string>
+#include <vector>
+
+#include <boost/function_output_iterator.hpp>
+
+struct string_appender {
+  string_appender(std::string& s) : m_str(s) { }
+  void operator()(const std::string& x) const {
+    m_str += x;
+  }
+  std::string& m_str;
+};
+
+int main(int, char*[])
+{
+  std::vector<std::string> x;
+  x.push_back("hello");
+  x.push_back(" ");
+  x.push_back("world");
+  x.push_back("!");
+
+  std::string s = "";
+  std::copy(x.begin(), x.end(), 
+	    boost::make_function_output_iterator(string_appender(s)));
+  
+  std::cout << s << std::endl;
+
+  return 0;
+}