Index: src/OFObject.h
==================================================================
--- src/OFObject.h
+++ src/OFObject.h
@@ -376,10 +376,37 @@
  * \return The old implementation
  */
 + (IMP)replaceInstanceMethod: (SEL)selector
 	 withMethodFromClass: (Class)class_;
 
+/**
+ * \brief Adds an instance method to the class.
+ *
+ * If the method already exists, nothing is done and NO is returned. If you want
+ * to change the implementation of a method, use
+ * setImplementation:forInstanceMethod:.
+ *
+ * \param selector The selector for the new method
+ * \param typeEncoding The type encoding for the new method
+ * \param implementation The implementation for the new method
+ * \return Whether the method has been added
+ */
++ (BOOL)addInstanceMethod: (SEL)selector
+	 withTypeEncoding: (const char*)typeEncoding
+	   implementation: (IMP)implementation;
+
+/**
+ * \brief Adds all instance methods from the specified class to the class that
+ *	  is the receiver.
+ *
+ * Existing methods will not be overriden, so that it behaves similar to normal
+ * inheritance.
+ *
+ * \param class The class from which the instance methods should be inherited
+ */
++ (void)inheritInstanceMethodsFromClass: (Class)class;
+
 /**
  * \brief Initializes an already allocated object.
  *
  * Derived classes may override this, but need to do self = [super init] before
  * they do any initialization themselves. init may never return nil, instead

Index: src/OFObject.m
==================================================================
--- src/OFObject.m
+++ src/OFObject.m
@@ -25,10 +25,12 @@
 #include <unistd.h>
 
 #include <assert.h>
 
 #import "OFObject.h"
+#import "OFArray.h"
+#import "OFIntrospection.h"
 #import "OFAutoreleasePool.h"
 
 #import "OFAllocFailedException.h"
 #import "OFEnumerationMutationException.h"
 #import "OFInitializationFailedException.h"
@@ -445,10 +447,48 @@
 	newImp = [class instanceMethodForSelector: selector];
 
 	return [self setImplementation: newImp
 		     forInstanceMethod: selector];
 }
+
++ (BOOL)addInstanceMethod: (SEL)selector
+	 withTypeEncoding: (const char*)typeEncoding
+	   implementation: (IMP)implementation
+{
+#if defined(OF_APPLE_RUNTIME) || defined(OF_GNU_RUNTIME)
+	return class_addMethod(self, selector, implementation, typeEncoding);
+#elif defined(OF_OLD_GNU_RUNTIME)
+	@throw [OFNotImplementedException newWithClass: isa
+					      selector: _cmd];
+#endif
+}
+
++ (void)inheritInstanceMethodsFromClass: (Class)class
+{
+	OFAutoreleasePool *pool = [[OFAutoreleasePool alloc] init];
+	OFIntrospection *introspection;
+	OFMethod **cArray;
+	size_t i, count;
+
+	introspection = [OFIntrospection introspectionWithClass: class];
+	cArray = [[introspection instanceMethods] cArray];
+	count = [[introspection instanceMethods] count];
+
+	for (i = 0; i < count; i++) {
+		SEL selector;
+		IMP implementation;
+
+		selector = [cArray[i] selector];
+		implementation = [class instanceMethodForSelector: selector];
+
+		[self addInstanceMethod: selector
+		       withTypeEncoding: [cArray[i] typeEncoding]
+			 implementation: implementation];
+	}
+
+	[pool release];
+}
 
 - init
 {
 	return self;
 }