From 27f6ec7b70fbbf2c1e26ef4a5b3f2a6bfb884078 Mon Sep 17 00:00:00 2001
From: Jonathan Turner <probata@hotmail.com>
Date: Wed, 1 Jul 2009 16:48:27 +0000
Subject: [PATCH] Change equation to clone rhs.  Add := ref equation.  Failed
 clones will ref copy

---
 chaiscript/chaiscript_eval.hpp   | 65 ++++++++++++++++++++++++++++----
 chaiscript/chaiscript_parser.hpp |  2 +-
 2 files changed, 59 insertions(+), 8 deletions(-)

diff --git a/chaiscript/chaiscript_eval.hpp b/chaiscript/chaiscript_eval.hpp
index e68e1654..f571b390 100644
--- a/chaiscript/chaiscript_eval.hpp
+++ b/chaiscript/chaiscript_eval.hpp
@@ -71,14 +71,65 @@ namespace chaiscript
                 retval = eval_token(ss, node->children.back());
                 if (node->children.size() > 1) {
                     for (i = node->children.size()-3; ((int)i) >= 0; i -= 2) {
-                        dispatchkit::Param_List_Builder plb;
-                        plb << eval_token(ss, node->children[i]);
-                        plb << retval;
-                        try {
-                            retval = dispatch(ss.get_function(node->children[i+1]->text), plb);
+                        if (node->children[i+1]->text == "=") {
+                            dispatchkit::Boxed_Value lhs = eval_token(ss, node->children[i]);
+                            if (lhs.is_unknown() || dispatchkit::Bootstrap::type_match(lhs, retval)) {
+                                try {
+                                    retval = dispatch(ss.get_function("clone"), dispatchkit::Param_List_Builder() << retval);
+                                    dispatchkit::Param_List_Builder plb;
+                                    plb << lhs;
+                                    plb << retval;
+                                    try {
+                                        retval = dispatch(ss.get_function(node->children[i+1]->text), plb);
+                                    }
+                                    catch(const dispatchkit::dispatch_error &e){
+                                        throw EvalError("Can not find appropriate '" + node->children[i+1]->text + "'", node->children[i+1]);
+                                    }
+                                }
+                                catch(const dispatchkit::dispatch_error &e){
+                                    //throw EvalError("Can not clone right hand side of equation", node->children[i+1]);
+                                    dispatchkit::Param_List_Builder plb;
+                                    plb << lhs;
+                                    plb << retval;
+                                    try {
+                                        retval = dispatch(ss.get_function("="), plb);
+                                    }
+                                    catch(const dispatchkit::dispatch_error &e){
+                                        throw EvalError("Can not find appropriate '" + node->children[i+1]->text + "'", node->children[i+1]);
+                                    }
+                                }
+                            }
+                            else {
+                                throw EvalError("Mismatched types in equation", node->children[i+1]);
+                            }
                         }
-                        catch(const dispatchkit::dispatch_error &e){
-                            throw EvalError("Can not find appropriate '" + node->children[i+1]->text + "'", node->children[i+1]);
+                        else if (node->children[i+1]->text == ":=") {
+                            dispatchkit::Boxed_Value lhs = eval_token(ss, node->children[i]);
+                            if (lhs.is_unknown() || dispatchkit::Bootstrap::type_match(lhs, retval)) {
+                                dispatchkit::Param_List_Builder plb;
+                                plb << lhs;
+                                plb << retval;
+                                try {
+                                    retval = dispatch(ss.get_function("="), plb);
+                                }
+                                catch(const dispatchkit::dispatch_error &e){
+                                    throw EvalError("Can not find appropriate '" + node->children[i+1]->text + "'", node->children[i+1]);
+                                }
+                            }
+                            else {
+                                throw EvalError("Mismatched types in equation", node->children[i+1]);
+                            }
+                        }
+                        else {
+                            dispatchkit::Param_List_Builder plb;
+                            plb << eval_token(ss, node->children[i]);
+                            plb << retval;
+                            try {
+                                retval = dispatch(ss.get_function(node->children[i+1]->text), plb);
+                            }
+                            catch(const dispatchkit::dispatch_error &e){
+                                throw EvalError("Can not find appropriate '" + node->children[i+1]->text + "'", node->children[i+1]);
+                            }
                         }
                     }
                 }
diff --git a/chaiscript/chaiscript_parser.hpp b/chaiscript/chaiscript_parser.hpp
index 284cdee6..95a80d58 100644
--- a/chaiscript/chaiscript_parser.hpp
+++ b/chaiscript/chaiscript_parser.hpp
@@ -1180,7 +1180,7 @@ namespace chaiscript
 
             if (Expression()) {
                 retval = true;
-                if (Symbol("=", true) || Symbol("+=", true) || Symbol("-=", true) || Symbol("*=", true) || Symbol("/=", true)) {
+                if (Symbol("=", true) || Symbol(":=", true) || Symbol("+=", true) || Symbol("-=", true) || Symbol("*=", true) || Symbol("/=", true)) {
                     if (!Equation()) {
                         throw Parse_Error("Incomplete equation", match_stack.back());
                     }