PasCocoa

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Revision as of 01:07, 23 February 2008 by Sekelsenmat (talk | contribs) (Implementation Details)

PasCocoa is the project to build object oriented bindings to use Cocoa in Pascal.

Objective-C to Pascal Bindings

Example

<delphi> program simplewindow;

{$mode delphi}

uses

 objc, ctypes, FPCMacOSAll, AppKit, Foundation;

const

 Str_Panel_Title = 'This is the title';
 Str_Panel_Message = 'This is the message';

var

 { classes }
 pool: NSAutoreleasePool;
 MainWindow: NSWindow;
 { strings }
 CFTitle, CFMessage: CFStringRef;
 { sizes }
 MainWindowRect: NSRect;

begin

 {  NSAutoreleasePool* pool = [[NSAutoreleasePool alloc] init]; }
 pool := NSAutoreleasePool.Create;
 // Creates the application NSApp object
 NSApp := NSApplication.sharedApplication;
 // Creates a simple window
 MainWindowRect.origin.x := 300.0;
 MainWindowRect.origin.y := 300.0;
 MainWindowRect.size.width := 300.0;
 MainWindowRect.size.height := 500.0;
 MainWindow := NSWindow.initWithContentRect(MainWindowRect,
   NSTitledWindowMask or NSClosableWindowMask or NSMiniaturizableWindowMask or NSResizableWindowMask,
   NSBackingStoreBuffered, NO);
   
 MainWindow.orderFrontRegardless;

// CreateMenu();

 { Enters main message loop }
 NSApp.run;
 {  [pool release]; }
 pool.Free;

end. </delphi>

Subversion

svn co https://lazarus-ccr.svn.sourceforge.net/svnroot/lazarus-ccr/bindings/objc objc
svn co https://lazarus-ccr.svn.sourceforge.net/svnroot/lazarus-ccr/bindings/pascocoa pascocoa

Implementation Details

The Cocoa headers contain several peculiarities that lead us to need a special structure for the bindings. First, several forward declarations of classes are done in a very unordently way. Pascal only accepts forward declarations of classes if they are all declared on the same type clause, and therefore a special session CLASSES is created on the include file.

The include file has a total of 3 separate sessions: HEADER, CLASSES and IMPLEMENTATION

Inclusion of headers in other frameworks should be removed, because the each framework is mapped to a pascal unit, and therefore all include files of a used framework are already accessible. Inclusion of headers of the same file framework should become include clauses which will used a C-styled ifdef mechanism to resolve in which order the include files will be added. This mechanism works fairly well and keeps the structure of the include files similar to the original one.

A tipical include file should have this structure:

<delphi> {%mainunit appkit.pas} {

       NSStatusBar.h
       Application Kit
       Copyright (c) 1997-2005, Apple Computer, Inc.
       All rights reserved.

}

{$ifdef HEADER} {$ifndef NSSTATUSBAR_PAS_H} {$define NSSTATUSBAR_PAS_H}

//insert constants, records and other interface declarations with the exception of classes

{$endif} {$endif} {$ifdef CLASSES} {$ifndef NSSTATUSBAR_PAS_H} {$define NSSTATUSBAR_PAS_H}

//declaration of classes and forward declarations of classes

{$endif} {$endif} {$ifdef IMPLEMENTATION}

//insert implementation declarations here. The order is not important on the implementation, so don't use extra ifdefs.

{$endif} </delphi>