Introduction To MacApp 2.0 And Object Oriented Programming Draft

Macintosh® Introduction to MacApp 2.0 and Object-Oriented Programming_ ( .. , • (! Draft April 14, 198<) Developer Technical Publications © Apple Computer, Inc. 1989 S APPLE COMPUTER, INC. This manual and the software described in it are copyrighted, with all rights reserved. Under the copyright laws, this manual or the software may not be copied, in whole or part, without written consent of Apple, except in the normal use of the software or to make a backup copy of the software. The same proprietary and copyright notices must be affixed to any permitted copies as were affixed to the original. This exception does not allow copies to be made for others, whether or not sold, but all of the material purchased (with all backup copies) may be sold, given, or loaned to another person. Under the law, copying includes translating into another language or format. You may use the software on any computer owned by you, but extra copies cannot be made for this purpose. The Apple logo is a registered trademark of Apple Computer, Inc. Use of the "keyboard" Apple logo (Option-Shift-K) for commercial purposes without the prior written consent of Apple may constitute trademark infringement and unfair competition in violation of federal and state laws. © Apple Computer, Inc., 1989 20525 Mariani Avenue Cupertino, CA 95014-6299 (408) 996-1010 Apple, the Apple logo, A/UX, I.aserWriter, MacApp, and Macintosh are registered trademarks of Apple Computer, Inc. APDA, AppleTalk, MPW, Finder, MultiFinder, ResEdit, and Rez are trademarks of Apple Computer, Inc. Adobe Illustrator is a trademark of Adobe Systems Incorporated. ITC Garamond and ITC Zapf Dingbats are registered trademarks of International Typeface Corporation. Microsoft is a registered trademark of Microsoft Corporation. POSTSCRIPT is a registered trademark of Adobe Systems Incorporated. UNIX is a registered trademark of AT&T Information Systems. Simultaneously published in the United States and Canada. Contents Figures and tables ix Preface xiii Prerequisites xv Hardware xv · Software xv What you should already know xvi Other books you should have xvii What this manual contains xvii How to use this manual xviii Nomenclature and typographic conventions xix Conventions in the MacApp code xix Graphical conventions xx Where to get information xxii About APDA xxii About Developer Programs xxii 1 Why MacApp? 1 What is MacApp? 3 Programming without MacApp 4 Programming with MacApp 5 The division of labor 5 The benefits of MacApp 7 ill 2 An Introduction to Object-Oriented Programming 9 The big picture 11 Record types and record variables 12 Classes and Instances 13 Flow of control in object.oriented programs 17 Classes 27 Inheritance 28 Method definitions 31 Override methods 32 Objects 34 An instance method 3S Inheritance and override methods 37 Override methods that don't call their inherited method 37 Override methods that do call their inherited method 38 Privacy between instances 41 Ramifications of …