[macosx][objective-c]Make cocoa app without Xcode

app.m

// clang -framework Cocoa app.m -o app
// ./app
#import <Cocoa/Cocoa.h>

int main()
{
  [NSAutoreleasePool new];
  id app = [NSApplication sharedApplication];
  [app setActivationPolicy:NSApplicationActivationPolicyRegular];
  
  NSRect frame = NSMakeRect(0, 0, 300, 300);
  id window = 
    [[[NSWindow alloc] initWithContentRect:frame
                                 styleMask:NSTitledWindowMask
                                   backing:NSBackingStoreBuffered
                                     defer:NO] autorelease];
  [window cascadeTopLeftFromPoint:NSMakePoint(10, 10)];
  [window setTitle:@"Hello"];
  [window makeKeyAndOrderFront:nil];
  
  id button = [[[NSButton alloc] initWithFrame:frame] autorelease];
  [button setTarget:app];
  [button setAction:@selector(terminate:)];
  [button setTitle:@"Quit"];
  [[window contentView] addSubview:button];
  
  [app activateIgnoringOtherApps:YES];
  [app run];
  return 0;
}

webkit.m

// clang -framework Cocoa -framework WebKit webkit.m -o webkit                                                                             
// ./webkit                                                                                                                                
#import <Cocoa/Cocoa.h>
#import <WebKit/WebKit.h>

int main()
{
  [NSAutoreleasePool new];
  id app = [NSApplication sharedApplication];
  [app setActivationPolicy:NSApplicationActivationPolicyRegular];

  NSRect frame = NSMakeRect(0, 0, 640, 480);
  int mask = NSTitledWindowMask | NSClosableWindowMask;
  id window =
    [[[NSWindow alloc] initWithContentRect:frame
                                 styleMask:mask
                                   backing:NSBackingStoreBuffered
                                     defer:NO] autorelease];
  [window cascadeTopLeftFromPoint:NSMakePoint(10, 10)];
  [window setTitle:@"Hello"];
  [window makeKeyAndOrderFront:nil];

  id nc = [NSNotificationCenter defaultCenter];
  [nc addObserver:app
         selector:@selector(terminate:)
             name:NSWindowWillCloseNotification
           object:window];

  id webview = [[[WebView alloc] initWithFrame:frame] autorelease];
  id url = [NSURL URLWithString:@"http://example.com/"];
  id req = [NSURLRequest requestWithURL:url];
  [[webview mainFrame] loadRequest:req];
  [[window contentView] addSubview:webview];

  [app activateIgnoringOtherApps:YES];
  [app run];
  return 0;
}

Do you know of any resources that I could use to learn how to code Mac stuff this way? I've been searching for hours and haven't come up with anything besides this code (which I am now studying intently, lol) and one other GitHub repo

Thanks!
Hayden