1 files changed, 163 insertions, 0 deletions
diff --git a/src/boost/libs/metaparse/example/calculator_with_parens/main.cpp b/src/boost/libs/metaparse/example/calculator_with_parens/main.cpp
new file mode 100644
index 000000000..9a154fc36
--- /dev/null
+++ b/src/boost/libs/metaparse/example/calculator_with_parens/main.cpp
@@ -0,0 +1,163 @@
+// Copyright Abel Sinkovics (abel@sinkovics.hu)  2014.
+// 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)
+
+#include <boost/metaparse/repeated.hpp>
+#include <boost/metaparse/sequence.hpp>
+#include <boost/metaparse/lit_c.hpp>
+#include <boost/metaparse/last_of.hpp>
+#include <boost/metaparse/first_of.hpp>
+#include <boost/metaparse/middle_of.hpp>
+#include <boost/metaparse/space.hpp>
+#include <boost/metaparse/int_.hpp>
+#include <boost/metaparse/foldl_reject_incomplete_start_with_parser.hpp>
+#include <boost/metaparse/one_of.hpp>
+#include <boost/metaparse/get_result.hpp>
+#include <boost/metaparse/token.hpp>
+#include <boost/metaparse/entire_input.hpp>
+#include <boost/metaparse/string.hpp>
+#include <boost/metaparse/build_parser.hpp>
+
+#include <boost/mpl/apply_wrap.hpp>
+#include <boost/mpl/fold.hpp>
+#include <boost/mpl/front.hpp>
+#include <boost/mpl/back.hpp>
+#include <boost/mpl/plus.hpp>
+#include <boost/mpl/minus.hpp>
+#include <boost/mpl/times.hpp>
+#include <boost/mpl/divides.hpp>
+#include <boost/mpl/bool.hpp>
+#include <boost/mpl/equal_to.hpp>
+#include <boost/mpl/eval_if.hpp>
+#include <boost/mpl/bool.hpp>
+
+using boost::metaparse::sequence;
+using boost::metaparse::lit_c;
+using boost::metaparse::last_of;
+using boost::metaparse::first_of;
+using boost::metaparse::middle_of;
+using boost::metaparse::space;
+using boost::metaparse::repeated;
+using boost::metaparse::build_parser;
+using boost::metaparse::int_;
+using boost::metaparse::foldl_reject_incomplete_start_with_parser;
+using boost::metaparse::get_result;
+using boost::metaparse::one_of;
+using boost::metaparse::token;
+using boost::metaparse::entire_input;
+
+using boost::mpl::apply_wrap1;
+using boost::mpl::fold;
+using boost::mpl::front;
+using boost::mpl::back;
+using boost::mpl::plus;
+using boost::mpl::minus;
+using boost::mpl::times;
+using boost::mpl::divides;
+using boost::mpl::eval_if;
+using boost::mpl::bool_;
+using boost::mpl::equal_to;
+using boost::mpl::bool_;
+
+/*
+ * The grammar
+ *
+ * expression ::= plus_exp
+ * plus_exp ::= prod_exp ((plus_token | minus_token) prod_exp)*
+ * prod_exp ::= int_token ((mult_token | div_token) simple_exp)*
+ * simple_exp ::= int_token | paren_exp
+ * paren_exp ::= open_paren_token expression close_paren_token
+ */
+
+typedef token<lit_c<'+'> > plus_token;
+typedef token<lit_c<'-'> > minus_token;
+typedef token<lit_c<'*'> > mult_token;
+typedef token<lit_c<'/'> > div_token;
+
+typedef token<lit_c<'('> > open_paren_token;
+typedef token<lit_c<')'> > close_paren_token;
+ 
+typedef token<int_> int_token;
+
+template <class T, char C>
+struct is_c : bool_<T::type::value == C> {};
+
+struct eval_plus
+{
+  template <class State, class C>
+  struct apply :
+    eval_if<
+      is_c<front<C>, '+'>,
+      plus<typename State::type, typename back<C>::type>,
+      minus<typename State::type, typename back<C>::type>
+    >
+  {};
+};
+
+struct eval_mult
+{
+  template <class State, class C>
+  struct apply :
+    eval_if<
+      is_c<front<C>, '*'>,
+      times<typename State::type, typename back<C>::type>,
+      divides<typename State::type, typename back<C>::type>
+    >
+  {};
+};
+
+struct plus_exp;
+
+typedef middle_of<open_paren_token, plus_exp, close_paren_token> paren_exp;
+
+typedef one_of<int_token, paren_exp> simple_exp;
+
+typedef
+  foldl_reject_incomplete_start_with_parser<
+    sequence<one_of<mult_token, div_token>, simple_exp>,
+    simple_exp,
+    eval_mult
+  >
+  prod_exp;
+  
+struct plus_exp :
+  foldl_reject_incomplete_start_with_parser<
+    sequence<one_of<plus_token, minus_token>, prod_exp>,
+    prod_exp,
+    eval_plus
+  >
+{};
+
+typedef last_of<repeated<space>, plus_exp> expression;
+
+typedef build_parser<entire_input<expression> > calculator_parser;
+
+#ifdef _STR
+#  error _STR already defined
+#endif
+#define _STR BOOST_METAPARSE_STRING
+
+#if BOOST_METAPARSE_STD < 2011
+int main()
+{
+  std::cout << "Please use a compiler that support constexpr" << std::endl;
+}
+#else
+int main()
+{
+  using std::cout;
+  using std::endl;
+  
+  cout
+    << apply_wrap1<calculator_parser, _STR("13")>::type::value << endl
+    << apply_wrap1<calculator_parser, _STR(" 1+ 2*4-6/2")>::type::value << endl
+    << apply_wrap1<calculator_parser, _STR("1+2*3+4")>::type::value << endl
+    << apply_wrap1<calculator_parser, _STR("(1+2)*(3+4)")>::type::value << endl
+    << apply_wrap1<calculator_parser, _STR("(2*3)+(4*5)")>::type::value << endl
+    << apply_wrap1<calculator_parser, _STR("2 * 3 + 4")>::type::value << endl
+    << apply_wrap1<calculator_parser, _STR("2 + (3 * 4)")>::type::value << endl
+    ;
+}
+#endif
+