RACBinding between UITextfield and a target that sends a signal when the text is changed programatically or using the keyboard.

gistfile1.m

- (RACSignal *)bindTextfield:(UITextField *)textField target:(id)target keypath:(NSString *)keypath
{
	textField.text = [target valueForKey:keypath];
	RACObservablePropertySubject *textFieldTextProperty = [RACObservablePropertySubject propertyWithTarget:textField keyPath:@keypath(textField,text)];
	RACSignal *textFieldEdited = [textField rac_textSignal];
	[[textFieldTextProperty binding] bindTo:[[RACObservablePropertySubject propertyWithTarget:target keyPath:keypath] binding]];
	[target rac_deriveProperty:keypath from:[textFieldEdited skip:1]];

	RACSignal *textValue = [[RACSignal merge:@[ textFieldEdited, textFieldTextProperty ]] distinctUntilChanged];
	return textValue;
}

gistfile2.m

// Updated after discussion with @jspahrsummers - I like this more.
- (RACSignal *)bindTextfield:(UITextField *)textField target:(id)target keypath:(NSString *)keypath
{
        RACPropertySubject *textProperty = [RACPropertySubject property];
	
	RACBinding *textPropertyBinding = [textProperty binding];
	[[textField rac_textSignal] subscribe:textPropertyBinding];
	RACBind(textField, text) = textPropertyBinding;
	
	[[textProperty binding] bindTo:[[RACObservablePropertySubject propertyWithTarget:target keyPath:keypath] binding]];
	return [textProperty startWith:[target valueForKeyPath:keypath]];
}