From 21328c2299eebc03c13478d7d214f9ed58d9688e Mon Sep 17 00:00:00 2001
From: Li Jin <dragon-fly@qq.com>
Date: Sun, 16 Jul 2017 23:47:58 +0800
Subject: remove uses of dynamic_cast.

---
 MoonParser/ast.cpp  |  2 ++
 MoonParser/ast.hpp  | 24 ++++++++++++++++++++----
 MoonParser/main.cpp |  9 +++++----
 3 files changed, 27 insertions(+), 8 deletions(-)

diff --git a/MoonParser/ast.cpp b/MoonParser/ast.cpp
index 916fdd7..090f5ee 100644
--- a/MoonParser/ast.cpp
+++ b/MoonParser/ast.cpp
@@ -8,6 +8,8 @@ namespace parserlib {
 //current AST container.
 static ast_container *_current = 0;
 
+int ast_type_id = 0;
+
 
 /** sets the container under construction to be this.
  */
diff --git a/MoonParser/ast.hpp b/MoonParser/ast.hpp
index 664c8af..01e2350 100644
--- a/MoonParser/ast.hpp
+++ b/MoonParser/ast.hpp
@@ -5,6 +5,7 @@
 #include <cassert>
 #include <list>
 #include <stdexcept>
+#include <type_traits>
 #include "parser.hpp"
 
 
@@ -21,6 +22,14 @@ template <class T> class ast;
  */
 typedef std::vector<ast_node *> ast_stack;
 
+extern int ast_type_id;
+
+template<class T>
+int ast_type()
+{
+	static int type = ast_type_id++;
+	return type;
+}
 
 /** Base class for AST nodes.
  */
@@ -58,6 +67,8 @@ public:
         @param user_data vector for storing user data.
      */
 	virtual void visit(void* user_data) {}
+
+	virtual int get_type() { return ast_type<ast_node>(); }
 private:
     //parent
     ast_node *m_parent;    
@@ -68,6 +79,11 @@ private:
     template <class T> friend class ast;
 };
 
+template<class T>
+T* ast_cast(ast_node *node)
+{
+	return ast_type<T>() == node->get_type() ? static_cast<T*>(node) : nullptr;
+}
 
 class ast_member;
 
@@ -254,7 +270,7 @@ public:
         ast_node *node = st.back();
         
         //get the object
-        T *obj = dynamic_cast<T *>(node);
+        T *obj = std::is_same<T, ast_node>() ? static_cast<T*>(node) : ast_cast<T>(node);
         
         //if the object is optional, simply return
         if (OPT) {
@@ -337,7 +353,7 @@ public:
 		ast_node *obj = nullptr;
 
 		using swallow = bool[];
-		(void)swallow{obj || (obj = dynamic_cast<Args*>(node))...};
+		(void)swallow{obj || (obj = std::is_same<Args, ast_node>() ? node : ast_cast<Args>(node))...};
 
         if (!obj) throw std::logic_error("invalid AST node");
 
@@ -414,7 +430,7 @@ public:
             ast_node *node = st.back();
             
             //get the object
-            T *obj = dynamic_cast<T *>(node);
+            T *obj = std::is_same<T, ast_node>() ? static_cast<T*>(node) : ast_cast<T>(node);
             
             //if the object was not not of the appropriate type,
             //end the list parsing
@@ -503,7 +519,7 @@ ast_node *parse(input &i, rule &g, error_list &el, void* ud);
  */
 template <class T> bool parse(input &i, rule &g, error_list &el, T *&ast, void* ud = nullptr) {
     ast_node *node = parse(i, g, el, ud);
-    ast = dynamic_cast<T *>(node);
+    ast = ast_cast<T>(node);
     if (ast) return true;
     delete node;
     return false;
diff --git a/MoonParser/main.cpp b/MoonParser/main.cpp
index 985fdcf..202a8df 100644
--- a/MoonParser/main.cpp
+++ b/MoonParser/main.cpp
@@ -50,7 +50,7 @@ struct Data
 rule Any = any();
 rule plain_space = *set(" \t");
 rule Break = nl(-expr('\r') >> '\n');
-rule White = *(set(" \t\r") | Break);
+rule White = *(set(" \t") | Break);
 rule Stop = Break | eof();
 rule Comment = "--" >> *(not_(set("\r\n")) >> Any) >> and_(Stop);
 rule Indent = *set(" \t");
@@ -556,12 +556,14 @@ rule BlockEnd = Block >> eof();
 #define AST_LEAF(type) \
 class type##_t : public ast_node \
 { \
-public:
+public: \
+	virtual int get_type() override { return ast_type<type##_t>(); }
 
 #define AST_NODE(type) \
 class type##_t : public ast_container \
 { \
-public:
+public: \
+	virtual int get_type() override { return ast_type<type##_t>(); }
 
 #define AST_END(type) \
 }; \
@@ -577,7 +579,6 @@ AST_LEAF(Num)
 			stream << static_cast<char>(*it);
 		}
 		stream >> value;
-		cout << value << '\n';
 	}
 AST_END(Num)
 
-- 
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