From c7689f18ec8043caef89f93374145a8e2c9c2ad5 Mon Sep 17 00:00:00 2001
From: Jason Turner <jason@emptycrate.com>
Date: Sat, 20 Jun 2015 10:28:27 -0600
Subject: [PATCH] Save local variable location after first pass

---
 .../chaiscript/dispatchkit/dispatchkit.hpp    | 36 +++++++++++++++----
 .../chaiscript/language/chaiscript_eval.hpp   |  6 ++--
 2 files changed, 33 insertions(+), 9 deletions(-)

diff --git a/include/chaiscript/dispatchkit/dispatchkit.hpp b/include/chaiscript/dispatchkit/dispatchkit.hpp
index 676b5f1..c451515 100644
--- a/include/chaiscript/dispatchkit/dispatchkit.hpp
+++ b/include/chaiscript/dispatchkit/dispatchkit.hpp
@@ -569,19 +569,41 @@ namespace chaiscript
         /// Searches the current stack for an object of the given name
         /// includes a special overload for the _ place holder object to
         /// ensure that it is always in scope.
-        Boxed_Value get_object(const std::string &name) const
+        Boxed_Value get_object(const std::string &name, uint32_t &t_loc) const
         {
-          auto &stack = get_stack_data();
+          enum class Loc : uint32_t {
+            located    = 0x80000000,
+            is_local   = 0x40000000,
+            stack_mask = 0x0FFF0000,
+            loc_mask   = 0x0000FFFF
+          };
 
-          // Is it in the stack?
-          for (auto stack_elem = stack.rbegin(); stack_elem != stack.rend(); ++stack_elem)
+          unsigned int loc = t_loc;
+
+          if (loc == 0)
           {
-            for (auto &s : (*stack_elem) )
+            auto &stack = get_stack_data();
+
+            // Is it in the stack?
+            for (auto stack_elem = stack.rbegin(); stack_elem != stack.rend(); ++stack_elem)
             {
-              if (s.first == name) {
-                return s.second;
+              for (auto s = stack_elem->begin(); s != stack_elem->end(); ++s )
+              {
+                if (s->first == name) {
+                  t_loc =  static_cast<uint32_t>(std::distance(stack.rbegin(), stack_elem) << 16)
+                         | static_cast<uint32_t>(std::distance(stack_elem->begin(), s))
+                         | static_cast<uint32_t>(Loc::located)
+                         | static_cast<uint32_t>(Loc::is_local);
+                  return s->second;
+                }
               }
             }
+
+            t_loc = static_cast<uint32_t>(Loc::located);
+          } else if (loc & static_cast<uint32_t>(Loc::is_local)) {
+            auto &stack = get_stack_data();
+
+            return stack[stack.size() - 1 - ((loc & static_cast<uint32_t>(Loc::stack_mask)) >> 16)][loc & static_cast<uint32_t>(Loc::loc_mask)].second;
           }
 
           // Is the value we are looking for a global?
diff --git a/include/chaiscript/language/chaiscript_eval.hpp b/include/chaiscript/language/chaiscript_eval.hpp
index 2b8b601..53deb6a 100644
--- a/include/chaiscript/language/chaiscript_eval.hpp
+++ b/include/chaiscript/language/chaiscript_eval.hpp
@@ -147,7 +147,7 @@ namespace chaiscript
       public:
         Id_AST_Node(const std::string &t_ast_node_text, Parse_Location t_loc) :
           AST_Node(t_ast_node_text, AST_Node_Type::Id, std::move(t_loc)),
-          m_value(get_value(t_ast_node_text))
+          m_value(get_value(t_ast_node_text)), m_loc(0)
       { }
 
         virtual ~Id_AST_Node() {}
@@ -157,7 +157,7 @@ namespace chaiscript
             return m_value;
           } else {
             try {
-              return t_ss.get_object(this->text);
+              return t_ss.get_object(this->text, m_loc);
             }
             catch (std::exception &) {
               throw exception::eval_error("Can not find object: " + this->text);
@@ -184,6 +184,8 @@ namespace chaiscript
         }
 
         Boxed_Value m_value;
+
+        mutable uint32_t m_loc;
     };
 
     struct Char_AST_Node : public AST_Node {