Add class MLKDynamicContext.

1 files changed, 63 insertions, 0 deletions

diff --git a/MLKDynamicContext.m b/MLKDynamicContext.m
new file mode 100644
index 0000000..2d8312f
--- /dev/null
+++ b/MLKDynamicContext.m
@@ -0,0 +1,63 @@
+/* -*- mode: objc; coding: utf-8 -*- */
+/* Copyright 2008, Matthias Benkard. */
+
+#import <Foundation/NSDictionary.h>
+#import <Foundation/NSArray.h>
+#import <Foundation/NSThread.h>
+
+#import "MLKDynamicContext.h"
+#import "MLKEnvironment.h"
+#import "MLKLinkedList.h"
+
+
+#define MAKE_ENVIRONMENT(variable, parent, parent_member)               \
+  (variable                                                             \
+   ? (id) [[MLKEnvironment alloc]                                       \
+            initWithParent:(parent                                      \
+                            ? (id) parent_member                        \
+                            : nil)                                      \
+                  bindings:vars]                                        \
+   : (id) (parent ? (id) parent_member : nil));
+
+
+@implementation MLKDynamicContext
+-(MLKDynamicContext *) initWithParent:(MLKDynamicContext *)aContext
+                            variables:(NSDictionary *)vars
+                             handlers:(NSDictionary *)handlers
+                             restarts:(NSDictionary *)restarts
+                       currentHandler:(MLKClosure *)handler
+{
+  _parent = (aContext ? aContext : [MLKDynamicContext currentContext]);
+  _environment = MAKE_ENVIRONMENT(vars, _parent, _parent->_environment);
+  _conditionHandlers = MAKE_ENVIRONMENT(handlers,
+                                        _parent,
+                                        _parent->_conditionHandlers);
+  _restarts = MAKE_ENVIRONMENT(restarts, _parent, _parent->_restarts);
+  _currentConditionHandler = (handler
+                              ? (id) handler
+                              : (_parent
+                                 ? (id) _parent->_currentConditionHandler
+                                 : nil));
+  return self;
+}
+
+-(MLKDynamicContext *) pushContext
+{
+  return [[[NSThread currentThread] threadDictionary]
+           objectForKey:@"MLKDynamicContext"];
+}
+
++(MLKDynamicContext *) currentContext
+{
+  return [[[NSThread currentThread] threadDictionary]
+           objectForKey:@"MLKDynamicContext"];
+}
+
++(MLKDynamicContext *) popContext
+{
+  MLKDynamicContext *context = [self currentContext];
+  [[[NSThread currentThread] threadDictionary] setObject:context->_parent
+                                               forKey:@"MLKDynamicContext"];
+  return context;
+}
+@end