From 1c6b2725b35d8413494c0bd1ae837fecf57dff12 Mon Sep 17 00:00:00 2001
From: Jason Turner <lefticus@gmail.com>
Date: Sat, 21 Nov 2009 06:02:17 +0000
Subject: [PATCH] Provide some hints for dispatches with lhs (first param) that
 is const

---
 include/chaiscript/dispatchkit/proxy_functions.hpp | 7 ++++++-
 include/chaiscript/language/chaiscript_eval.hpp    | 2 +-
 2 files changed, 7 insertions(+), 2 deletions(-)

diff --git a/include/chaiscript/dispatchkit/proxy_functions.hpp b/include/chaiscript/dispatchkit/proxy_functions.hpp
index 720d145..0d83b83 100644
--- a/include/chaiscript/dispatchkit/proxy_functions.hpp
+++ b/include/chaiscript/dispatchkit/proxy_functions.hpp
@@ -496,6 +496,11 @@ namespace chaiscript
     {
     }
 
+    dispatch_error(bool is_const) throw()
+      : std::runtime_error(std::string("No matching function to dispatch to") + (is_const?", parameter is const":""))
+      {
+      }
+
     virtual ~dispatch_error() throw() {}
   };
 
@@ -526,7 +531,7 @@ namespace chaiscript
       ++begin;
     }
 
-    throw dispatch_error();
+    throw dispatch_error(plist.empty()?false:plist[0].is_const());
   }
 
   /**
diff --git a/include/chaiscript/language/chaiscript_eval.hpp b/include/chaiscript/language/chaiscript_eval.hpp
index a2f2077..d75e957 100644
--- a/include/chaiscript/language/chaiscript_eval.hpp
+++ b/include/chaiscript/language/chaiscript_eval.hpp
@@ -182,7 +182,7 @@ namespace chaiscript
                             retval = ss.call_function(node->children[i+1]->text, plb);
                         }
                         catch(const dispatch_error &){
-                            throw Eval_Error("Mismatched types in equation", node->children[i+1]);
+                            throw Eval_Error(std::string("Mismatched types in equation") + (lhs.is_const()?", lhs is const.":"."), node->children[i+1]);
                         }
                     }
                     catch(const dispatch_error &){