Redefintition of SidebarDelegate as different kind of symbol - objective-c

Question

I have the following Objective C code that keeps error complaining I am redefining it when I not!! I am trying to implement a NSTableViewDelegate thing but xcode keep complaining
#import "AppDelegate.h"
#import <AppKit/AppKit.h>
#implementation AppDelegate
- (void)applicationDidFinishLaunching:(NSNotification *)aNotification
{
// add Hello World to sidebar
[self.Sidebar.tableView insertValue:0 atIndex:0 inPropertyWithKey:#"Hello World!"];
[self.Sidebar.tableView setDelegate: SidebarDelegate()]
// reload data
[self.Sidebar.tableView reloadData];
}
- (BOOL)applicationShouldTerminateAfterLastWindowClosed:(NSApplication *)theApplication {
return YES;
}
#end
// Sidebar Delage
#implementation SidebarDelegate : NSObject <NSTableViewDelegate, NSTableViewDataSource>;
// setting data
- (void)tableView:(NSTableView *)aTableView setObjectValue:(id)anObject forTableColumn:(NSTableColumn *)aTableColumn row:(NSInteger)rowIndex
{
anObject = #"Apples";
}
// height
- (CGFloat)tableView:(NSTableView *)tableView heightOfRow:(NSInteger)row
{
return 20;
}
- (BOOL)tableView:(NSTableView *)aTableView shouldSelectRow:(NSInteger)rowIndex
{
NSLog(#"%ld", (long)rowIndex);
return ((long)rowIndex % 2) == 0;
}
- (NSInteger)numberOfRowsInTableView:(NSTableView *)aTableView
{
return 4;
}
#end

Answer 1

replace
[self.Sidebar.tableView setDelegate: SidebarDelegate()];
with
SidebarDelegate *sidebarDelegate = [[SidebarDelegate alloc] init];
[self.Sidebar.tableView setDelegate:sidebarDelegate];

Answer 2

This line:
[self.Sidebar.tableView setDelegate: SidebarDelegate()];
implicitly creates a function named SidebarDelegate() of the form
int SidebarDelegate(void)
Thus, when you try to define a class of the same name, you overwrite the symbol in an unacceptable way. You need to initialize an instance of SidebarDelegate and pass that as the TableView's delegate not, I will presume, just pass the name of the class.