From 80ed8eb505ce8448b25cea64b4f8c0121482e403 Mon Sep 17 00:00:00 2001
From: Jason Turner <lefticus@gmail.com>
Date: Sun, 21 Jun 2009 20:07:11 +0000
Subject: [PATCH] Make EvalError a subclass of runtime_error and provide the
 std::exception with a robust description for easier debugging of
 callback/scripted function calls

---
 chaiscript/chaiscript_engine.hpp | 6 +++---
 chaiscript/chaiscript_eval.hpp   | 9 +++++++--
 samples/callbacks.chai           | 1 +
 3 files changed, 11 insertions(+), 5 deletions(-)

diff --git a/chaiscript/chaiscript_engine.hpp b/chaiscript/chaiscript_engine.hpp
index fbbb24a..fc2fefb 100644
--- a/chaiscript/chaiscript_engine.hpp
+++ b/chaiscript/chaiscript_engine.hpp
@@ -29,12 +29,12 @@ namespace chaiscript
             try {
                 val = dispatchkit::Cast_Helper<std::string &>()(vals[0]);
             }
-            catch (std::exception &e) {
-                throw EvalError("Can not evaluate string: " + val, langkit::TokenPtr());
-            }
             catch (EvalError &ee) {
                 throw EvalError("Can not evaluate string: " + val + " reason: " + ee.reason, langkit::TokenPtr());
             }
+            catch (std::exception &e) {
+                throw EvalError("Can not evaluate string: " + val, langkit::TokenPtr());
+            }
             return evaluate_string(val);
         }
 
diff --git a/chaiscript/chaiscript_eval.hpp b/chaiscript/chaiscript_eval.hpp
index 4021b82..fcc1a44 100644
--- a/chaiscript/chaiscript_eval.hpp
+++ b/chaiscript/chaiscript_eval.hpp
@@ -15,11 +15,16 @@ namespace chaiscript
         ParserError(const std::string &why, const langkit::TokenPtr where) : reason(why), location(where){ }
     };
 
-    struct EvalError {
+    struct EvalError : public std::runtime_error {
         std::string reason;
         langkit::TokenPtr location;
 
-        EvalError(const std::string &why, const langkit::TokenPtr where) : reason(why), location(where) { }
+        EvalError(const std::string &why, const langkit::TokenPtr where) 
+          : std::runtime_error("Eval error: \"" + why + "\" in '" 
+              + where->filename + "' line: " + boost::lexical_cast<std::string>(where->start.line+1)), 
+            reason(why), location(where) { }
+
+        virtual ~EvalError() throw() {}
     };
 
     struct ReturnValue {
diff --git a/samples/callbacks.chai b/samples/callbacks.chai
index de16629..0d5394c 100644
--- a/samples/callbacks.chai
+++ b/samples/callbacks.chai
@@ -4,4 +4,5 @@ cb_handler.add_callbacks( function() { "DivOnePtTwo"; }, function (x) { x / 1.2;
 
 
 
+cb_handler.add_callbacks( function() { "DivOnePtTwo"; }, function (x) { blargh; } );