4 files changed, 75 insertions, 15 deletions

diff --git a/MLKDynamicContext.h b/MLKDynamicContext.h
index aa3614f..bd08800 100644
--- a/MLKDynamicContext.h
+++ b/MLKDynamicContext.h
@@ -25,8 +25,8 @@
   MLKEnvironment *_conditionHandlers;
   MLKEnvironment *_restarts;
   MLKEnvironment *_catchTags;
-  MLKClosure *_currentConditionHandler;  // needed for the Condition Firewall
   MLKEnvironment *_environment;
+  MLKEnvironment *_activeHandlerEnvironment;  // needed for the Condition Firewall
   MLKDynamicContext *_parent;
 }
 
@@ -35,7 +35,7 @@
                              handlers:(NSDictionary *)handlers
                              restarts:(NSDictionary *)restarts
                             catchTags:(NSDictionary *)catchTags
-                       currentHandler:(MLKClosure *)handler;
+             activeHandlerEnvironment:(MLKEnvironment *)handlerEnv;
 
 -(MLKDynamicContext *) pushContext;
 
diff --git a/MLKDynamicContext.m b/MLKDynamicContext.m
index c034eac..d08deaa 100644
--- a/MLKDynamicContext.m
+++ b/MLKDynamicContext.m
@@ -41,7 +41,7 @@
                              handlers:(NSDictionary *)handlers
                              restarts:(NSDictionary *)restarts
                             catchTags:(NSDictionary *)catchTags
-                       currentHandler:(MLKClosure *)handler
+             activeHandlerEnvironment:(MLKEnvironment *)handlerEnv;
 {
   self = [super init];
   ASSIGN (_parent, (aContext ? aContext : [MLKDynamicContext currentContext]));
@@ -51,11 +51,12 @@
                                         _parent->_conditionHandlers);
   _restarts = MAKE_ENVIRONMENT(restarts, _parent, _parent->_restarts);
   _catchTags = MAKE_ENVIRONMENT(catchTags, _parent, _parent->_catchTags);
-  _currentConditionHandler = (handler
-                              ? (id) handler
-                              : (_parent
-                                 ? (id) _parent->_currentConditionHandler
-                                 : nil));
+  ASSIGN (_activeHandlerEnvironment,
+          handlerEnv
+          ? (id) handlerEnv
+          : (_parent
+             ? (id) (_parent->_activeHandlerEnvironment)
+             : nil));
   return self;
 }
 
@@ -86,19 +87,59 @@
 
 -(id) findRestart:(MLKSymbol *)symbol
 {
-  return [_restarts valueForBinding:symbol];
+  NS_DURING
+    {
+      return [_restarts valueForBinding:symbol];
+    }
+  NS_HANDLER
+    {
+      if ([[localException name] isEqualToString: @"MLKUndefinedVariableException"])
+        NS_VALUERETURN (nil, id);
+      else
+        [localException raise];
+    }
+  NS_ENDHANDLER;
+
+  return nil;
 }
 
-/*
 -(id) findHandler:(MLKSymbol *)symbol
 {
-  // ???
+  NS_DURING
+    {
+      if (_activeHandlerEnvironment)
+        return [[_activeHandlerEnvironment parent] valueForBinding:symbol];
+      else
+        return [_conditionHandlers valueForBinding:symbol];
+    }
+  NS_HANDLER
+    {
+      if ([[localException name] isEqualToString: @"MLKUndefinedVariableException"])
+        NS_VALUERETURN (nil, id);
+      else
+        [localException raise];
+    }
+  NS_ENDHANDLER;
+
+  return nil;
 }
-*/
 
 -(id) findCatchTag:(MLKSymbol *)symbol
 {
-  return [_catchTags valueForBinding:symbol];
+  NS_DURING
+    {
+      return [_catchTags valueForBinding:symbol];
+    }
+  NS_HANDLER
+    {
+      if ([[localException name] isEqualToString: @"MLKUndefinedVariableException"])
+        NS_VALUERETURN (nil, id);
+      else
+        [localException raise];
+    }
+  NS_ENDHANDLER;
+
+  return nil;
 }
 
 -(void) dealloc
@@ -106,7 +147,7 @@
   RELEASE (_conditionHandlers);
   RELEASE (_restarts);
   RELEASE (_catchTags);
-  RELEASE (_currentConditionHandler);
+  RELEASE (_activeHandlerEnvironment);
   RELEASE (_environment);
   RELEASE (_parent);
   [super dealloc];
diff --git a/MLKEnvironment.h b/MLKEnvironment.h
index 9d621e8..b70b5b9 100644
--- a/MLKEnvironment.h
+++ b/MLKEnvironment.h
@@ -32,11 +32,15 @@
 -(MLKEnvironment *) initWithBindings:(NSDictionary *)bindings;
 -(MLKEnvironment *) initWithParent:(MLKEnvironment *)parent bindings:(NSDictionary *)bindings;
 
+-(MLKEnvironment *) parent;
+
 -(void) addBindings:(NSDictionary *)bindings;
 -(void) addBinding:(MLKSymbol *)symbol to:(id)value;
 -(void) setBinding:(MLKSymbol *)symbol to:(id)value;
 -(id) valueForBinding:(MLKSymbol *)symbol;
 
+-(MLKEnvironment *) environmentForBinding:(MLKSymbol *)symbol;
+
 // Private methods.
 -(void) setBinding:(MLKSymbol *)symbol to:(id)value inEnvironment:(MLKEnvironment *)env;
 -(id) valueForBinding:(MLKSymbol *)symbol inEnvironment:(MLKEnvironment *)env;
diff --git a/MLKEnvironment.m b/MLKEnvironment.m
index 6011f90..8a7c270 100644
--- a/MLKEnvironment.m
+++ b/MLKEnvironment.m
@@ -48,6 +48,11 @@
   return [self initWithParent:nil bindings:bindings];
 }
 
+-(MLKEnvironment *) parent
+{
+  return _parent;
+}
+
 -(void) setBinding:(MLKSymbol *)symbol to:(id)value
 {
   [self setBinding:symbol to:value inEnvironment:self];
@@ -81,7 +86,7 @@
     else
       [[[MLKUndefinedVariableException alloc] initWithEnvironment:env
                                               variableName:symbol]
-        raise];;
+        raise];
   
   return nil;  // avoid a stupid compiler warning
 }
@@ -96,6 +101,16 @@
   [_bindings setObject:value forKey:symbol];
 }
 
+-(MLKEnvironment *) environmentForBinding:(MLKSymbol *)symbol
+{
+  if ([[_bindings allKeys] containsObject:symbol])
+    return self;
+  else if (_parent)
+    return [_parent environmentForBinding:symbol];
+  else
+    return nil;
+}
+
 -(void) dealloc
 {
   RELEASE (_bindings);