Allow for parse time evaluation of const values.

The goal is to allow for more evaluation at parse time, in general, to
increase eval time performance.

 - Make AST_Node non-constructable except by derived classes.
 - Make data in AST_Node const (as much as possible).
 - Replace reflection "text = " with replace_child() (where the
   replacement must be with a new parse tree).
 - Evaluate floats, strings, ints, chars at parse time to avoid repeat
   evaluations (~10% speed up in loops in -O3)

include/chaiscript/language/chaiscript_common.hpp

@@ -61,48 +61,57 @@ namespace chaiscript
    * The struct that doubles as both a parser ast_node and an AST node
    */
   struct AST_Node {
-    std::string text;
+    public:
-    int identifier;
+      const std::string text;
-    boost::shared_ptr<std::string> filename;
+      const int identifier;
-    File_Position start, end;
+      boost::shared_ptr<const std::string> filename;
-    std::vector<AST_NodePtr> children;
+      File_Position start, end;
-    AST_NodePtr annotation;
+      std::vector<AST_NodePtr> children;
+      AST_NodePtr annotation;
 
-    AST_Node(const std::string &t_ast_node_text, int t_id, const boost::shared_ptr<std::string> &t_fname, 
+      /**
-             int t_start_line, int t_start_col, int t_end_line, int t_end_col) :
+       * Prints the contents of an AST node, including its children, recursively
-      text(t_ast_node_text), identifier(t_id), filename(t_fname),
+       */
-      start(t_start_line, t_start_col), end(t_end_line, t_end_col)
+      std::string to_string(std::string t_prepend = "") {
-    {
+        std::ostringstream oss;
-    }
 
-    AST_Node(const std::string &t_ast_node_text, int t_id, const boost::shared_ptr<std::string> &t_fname) :
+        oss << t_prepend << "(" << ast_node_type_to_string(this->identifier) << ") "
-      text(t_ast_node_text), identifier(t_id), filename(t_fname) {}
+            << this->text << " : " << this->start.line << ", " << this->start.column << std::endl;
         
-    virtual ~AST_Node() {}
+        for (unsigned int j = 0; j < this->children.size(); ++j) {
-
+          oss << this->children[j]->to_string(t_prepend + "  ");
-    /**
+        }
-     * Prints the contents of an AST node, including its children, recursively
+        return oss.str();
-     */
-    std::string to_string(std::string t_prepend = "") {
-      std::ostringstream oss;
-
-      oss << t_prepend << "(" << ast_node_type_to_string(this->identifier) << ") "
-          << this->text << " : " << this->start.line << ", " << this->start.column << std::endl;
-      
-      for (unsigned int j = 0; j < this->children.size(); ++j) {
-        oss << this->children[j]->to_string(t_prepend + "  ");
       }
-      return oss.str();
-    }
 
-    std::string internal_to_string() {
+      std::string internal_to_string() {
-      return to_string();
+        return to_string();
-    }
+      }
+
+      virtual Boxed_Value eval(chaiscript::detail::Dispatch_Engine &) 
+      {
+        Boxed_Value bv;
+        throw std::runtime_error("Undispatched ast_node (internal error)");
+      }
+
+      void replace_child(const AST_NodePtr &t_child, const AST_NodePtr &t_new_child)
+      {
+        std::replace(children.begin(), children.end(), t_child, t_new_child);
+      }
+
+    protected:
+      AST_Node(const std::string &t_ast_node_text, int t_id, const boost::shared_ptr<std::string> &t_fname, 
+          int t_start_line, int t_start_col, int t_end_line, int t_end_col) :
+        text(t_ast_node_text), identifier(t_id), filename(t_fname),
+        start(t_start_line, t_start_col), end(t_end_line, t_end_col)
+      {
+      }
+
+      AST_Node(const std::string &t_ast_node_text, int t_id, const boost::shared_ptr<std::string> &t_fname) :
+        text(t_ast_node_text), identifier(t_id), filename(t_fname) {}
+
+      virtual ~AST_Node() {}
 
-    virtual Boxed_Value eval(chaiscript::detail::Dispatch_Engine &) {
-      Boxed_Value bv;
-      throw std::runtime_error("Undispatched ast_node (internal error)");
-    }
   };
 
 

include/chaiscript/language/chaiscript_eval.hpp

@@ -89,23 +89,30 @@ namespace chaiscript
     struct Int_AST_Node : public AST_Node {
       public:
         Int_AST_Node(const std::string &t_ast_node_text = "", int t_id = AST_Node_Type::Int, const boost::shared_ptr<std::string> &t_fname=boost::shared_ptr<std::string>(), int t_start_line = 0, int t_start_col = 0, int t_end_line = 0, int t_end_col = 0) :
-          AST_Node(t_ast_node_text, t_id, t_fname, t_start_line, t_start_col, t_end_line, t_end_col) { }
+          AST_Node(t_ast_node_text, t_id, t_fname, t_start_line, t_start_col, t_end_line, t_end_col), m_value(const_var(int(atoi(this->text.c_str())))) { }
         virtual ~Int_AST_Node() {}
         virtual Boxed_Value eval(chaiscript::detail::Dispatch_Engine &){
-          return const_var(int(atoi(this->text.c_str())));
+          return m_value;
         }
 
+      private:
+        Boxed_Value m_value;
+
     };
 
     struct Float_AST_Node : public AST_Node {
       public:
         Float_AST_Node(const std::string &t_ast_node_text = "", int t_id = AST_Node_Type::Float, const boost::shared_ptr<std::string> &t_fname=boost::shared_ptr<std::string>(), int t_start_line = 0, int t_start_col = 0, int t_end_line = 0, int t_end_col = 0) :
-          AST_Node(t_ast_node_text, t_id, t_fname, t_start_line, t_start_col, t_end_line, t_end_col) { }
+          AST_Node(t_ast_node_text, t_id, t_fname, t_start_line, t_start_col, t_end_line, t_end_col),
+          m_value(const_var(double(atof(this->text.c_str())))) { }
         virtual ~Float_AST_Node() {}
         virtual Boxed_Value eval(chaiscript::detail::Dispatch_Engine &){
-          return const_var(double(atof(this->text.c_str())));
+          return m_value;
         }
 
+      private:
+        Boxed_Value m_value;
+
     };
 
     struct Id_AST_Node : public AST_Node {
@@ -472,7 +479,7 @@ namespace chaiscript
               }
               catch(const exception::dispatch_error &e){
                 t_ss.set_stack(prev_stack);
-                throw exception::eval_error(std::string(e.what()));
+                throw exception::eval_error(std::string(e.what()) + " for function: " + fun_name);
               }
               catch(detail::Return_Value &rv) {
                 t_ss.set_stack(prev_stack);
@@ -510,23 +517,30 @@ namespace chaiscript
     struct Quoted_String_AST_Node : public AST_Node {
       public:
         Quoted_String_AST_Node(const std::string &t_ast_node_text = "", int t_id = AST_Node_Type::Quoted_String, const boost::shared_ptr<std::string> &t_fname=boost::shared_ptr<std::string>(), int t_start_line = 0, int t_start_col = 0, int t_end_line = 0, int t_end_col = 0) :
-          AST_Node(t_ast_node_text, t_id, t_fname, t_start_line, t_start_col, t_end_line, t_end_col) { }
+          AST_Node(t_ast_node_text, t_id, t_fname, t_start_line, t_start_col, t_end_line, t_end_col),
+          m_value(const_var(this->text)) { }
         virtual ~Quoted_String_AST_Node() {}
-        virtual Boxed_Value eval(chaiscript::detail::Dispatch_Engine &){
+        virtual Boxed_Value eval(chaiscript::detail::Dispatch_Engine &) {
-          return const_var(this->text);
+          return m_value;
         }
 
+      private:
+        Boxed_Value m_value;
+
     };
 
     struct Single_Quoted_String_AST_Node : public AST_Node {
       public:
         Single_Quoted_String_AST_Node(const std::string &t_ast_node_text = "", int t_id = AST_Node_Type::Single_Quoted_String, const boost::shared_ptr<std::string> &t_fname=boost::shared_ptr<std::string>(), int t_start_line = 0, int t_start_col = 0, int t_end_line = 0, int t_end_col = 0) :
-          AST_Node(t_ast_node_text, t_id, t_fname, t_start_line, t_start_col, t_end_line, t_end_col) { }
+          AST_Node(t_ast_node_text, t_id, t_fname, t_start_line, t_start_col, t_end_line, t_end_col),
+          m_value(const_var(char(this->text[0]))) { }
         virtual ~Single_Quoted_String_AST_Node() {}
         virtual Boxed_Value eval(chaiscript::detail::Dispatch_Engine &){
-          return const_var(char(this->text[0]));
+          return m_value;
         }
 
+      private:
+        Boxed_Value m_value;
     };
 
     struct Lambda_AST_Node : public AST_Node {
@@ -656,7 +670,7 @@ namespace chaiscript
         While_AST_Node(const std::string &t_ast_node_text = "", int t_id = AST_Node_Type::While, const boost::shared_ptr<std::string> &t_fname=boost::shared_ptr<std::string>(), int t_start_line = 0, int t_start_col = 0, int t_end_line = 0, int t_end_col = 0) :
           AST_Node(t_ast_node_text, t_id, t_fname, t_start_line, t_start_col, t_end_line, t_end_col) { }
         virtual ~While_AST_Node() {}
-        virtual Boxed_Value eval(chaiscript::detail::Dispatch_Engine &t_ss){
+        virtual Boxed_Value eval(chaiscript::detail::Dispatch_Engine &t_ss) {
           bool cond;
 
           t_ss.new_scope();

include/chaiscript/language/chaiscript_parser.hpp

@@ -1312,7 +1312,12 @@ namespace chaiscript
               has_matches = false;
               if (Keyword("else", true)) {
                 if (Keyword("if")) {
-                  m_match_stack.back()->text = "else if";
+                  AST_NodePtr back(m_match_stack.back());
+                  m_match_stack.back() = AST_NodePtr(new eval::If_AST_Node("else if", back->identifier)); 
+                  m_match_stack.back()->start = back->start;
+                  m_match_stack.back()->end = back->end;
+                  m_match_stack.back()->children = back->children;
+                  m_match_stack.back()->annotation = back->annotation;
                   if (!Char('(')) {
                     throw exception::eval_error("Incomplete 'else if' expression", File_Position(m_line, m_col), *m_filename);
                   }

src/reflection.cpp

@@ -62,7 +62,7 @@ CHAISCRIPT_MODULE_EXPORT  chaiscript::ModulePtr create_chaiscript_module_reflect
 
   CHAISCRIPT_CLASS( m, 
       chaiscript::AST_Node,
-      (chaiscript::AST_Node (const std::string &, int, const boost::shared_ptr<std::string> &)),
+      ,
       ((text))
       ((identifier))
       ((filename))
@@ -70,6 +70,7 @@ CHAISCRIPT_MODULE_EXPORT  chaiscript::ModulePtr create_chaiscript_module_reflect
       ((end))
       ((internal_to_string))
       ((children))
+      ((replace_child))
     );
 
   CHAISCRIPT_CLASS( m, 

unittests/reflection_test.chai

@@ -8,7 +8,11 @@ assert_equal(eval(a), 7)
 var childs := a.children.front().children
 var node := childs[0]
 
-node.text = "9"
+var parser2 := ChaiScript_Parser()
+parser2.parse("9", "INPUT")
+
+
+a.children.front().replace_child(childs[0], parser2.ast())
 
 assert_equal(eval(a), 13)
 assert_equal(node.filename, "INPUT")