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567 lines
16 KiB
Text
567 lines
16 KiB
Text
\input texinfo @c -*-texinfo-*-
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@c @setfilename objective-c.info
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@ifinfo
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@format
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START-INFO-DIR-ENTRY
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* Objective-C: (objective-c). The GNU Objective-C Language Manual
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END-INFO-DIR-ENTRY
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@end format
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@end ifinfo
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@ifinfo
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Copyright @copyright{} 1994 Andrew Kachites McCallum and Free Software
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Foundation, Inc.
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Permission is granted to make and distribute verbatim copies of
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this manual provided the copyright notice and this permission notice
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are preserved on all copies.
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Permission is granted to copy and distribute modified versions of this
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manual under the conditions for verbatim copying, provided also that
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the entire resulting derived work is distributed under the terms of a
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permission notice identical to this one.
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Permission is granted to copy and distribute translations of this manual
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into another language, under the above conditions for modified versions.
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@end ifinfo
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@setchapternewpage odd
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@settitle Objective-C Language Manual
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@titlepage
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@finalout
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@title The GNU Objective-C Language Manual
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@author Andrew Kachites McCallum
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@page
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@vskip 0pt plus 1filll
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Copyright @copyright{} 1994 Andrew Kachites McCallum and Free Software
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Foundation, Inc.
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Permission is granted to make and distribute verbatim copies of
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this manual provided the copyright notice and this permission notice
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are preserved on all copies.
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Permission is granted to copy and distribute modified versions of this
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manual under the conditions for verbatim copying, provided also that
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the entire resulting derived work is distributed under the terms of a
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permission notice identical to this one.
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Permission is granted to copy and distribute translations of this manual
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into another language, under the above conditions for modified versions.
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@end titlepage
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@node Top, Introduction, (dir), (dir)
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@top Main Menu
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This is the manual for the GNU Objective-C language.
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@menu
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* Introduction::
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* Objects Messages and Classes::
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* Techniques::
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* Advanced Features::
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* Builtin Classes::
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Appendices
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* History and Comparisons::
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* Runtime Internals::
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* Hacking for Efficiency::
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* Debugging ObjC::
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* Language Summary:: A summary of ObjC syntax and semantics.
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Indeces
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* Concept Index::
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* Function Index::
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@end menu
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@c ******************************************************************
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@node Introduction, Objects Messages and Classes, Top, Top
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@chapter Introduction
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This manual describes the GNU Objective-C language. It is assumed that
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the reader is already familiar with ANSI C.
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@section Overview
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Objective-C is an object-oriented computer programming language. It is
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a superset of ANSI C and provides classes and message passing similar to
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Smalltalk. (xxx Lifted from FAQ. General question: Should I lift from
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the Objc FAQ? Is there a problem with this? If in doubt, I'll write it
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all myself.)
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@menu
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* Caveats:: Flaws and requests for help.
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* Conventions:: How this manual is formatted.
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* Acknowledgements:: The authors and editors of this manual.
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@end menu
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@node Caveats, Conventions, Introduction, Introduction
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@section Caveats
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This manual is pre-alpha. I am now trying to determine the organization
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of manual. Afterward, sections will be filled in with text.
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If you have suggestions for additional topics or organizational changes,
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please email them to @samp{mccallum@@cs.rochester.edu}.
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@node Conventions, Acknowledgements, Caveats, Introduction
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@section Conventions
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@node Acknowledgements, , Conventions, Introduction
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@section Acknowledgements
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@c ******************************************************************
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@node Objects Messages and Classes, Techniques, Introduction, Top
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@chapter Objects, Messages and Classes
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Object-oriented programming made up of objects, the messages they can
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receive and the classes that specify how objects are related.
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@menu
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* Objects::
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* Messages::
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* Classes and Instances::
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* Inheritance of Subclasses::
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@end menu
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@node Objects, Messages, Objects Messages and Classes, Objects Messages and Classes
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@section Objects Encapsulate Data and Operations
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Procedures and data in a bundle. Abstraction.
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@node Messages, Classes and Instances, Objects, Objects Messages and Classes
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@section Messages Request Operations
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@c @section Sending a Message to an Object
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@smallexample
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[@var{receiver} @var{message}];
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@end smallexample
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Messages with arguments.
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Return types.
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Argument types.
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Messages to @samp{nil}.
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@node Classes and Instances, Inheritance of Subclasses, Messages, Objects Messages and Classes
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@section Classes Define Objects
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@c @section Classes and Instances
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@c @section Classes Define their Instances
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Inheritance of methods and instance variables.
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Overriding methods.
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Syntax of @@interface, @@implementation.
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Messages to super.
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Creating and freeing instances.
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@node Inheritance of Subclasses, , Classes and Instances, Objects Messages and Classes
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@section Inheritance of Subclasses
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@c @section Classes are Defined in an Inheritance Heirarchy
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@c @section Subclasses and Inheritance
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@node Techniques, Advanced Features, Objects Messages and Classes, Top
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@chapter Programming Techniques and Conventions
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@section Overriding Methods
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@section Abstract Superclasses
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@section Returning @samp{self}
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@section ...more here...
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@c ******************************************************************
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@node Advanced Features, Builtin Classes, Techniques, Top
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@chapter Advanced Features
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@menu
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* Runtime Message Variation::
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* Forwarding a Message:: Using @samp{-forward::} and @samp{-performv::}.
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* Adding Methods to a Class:: Defining categories.
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* Posing as a Superclass::
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* Protocols of Messages::
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* Class initialization:: Defining @samp{+initialize}.
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* Encoding Types::
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* Structure of an Object:: Using @@defs().
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* Archiving:: Using @samp{-write:} and @samp{-read:}.
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@end menu
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@node Runtime Message Variation, Forwarding a Message, Advanced Features, Advanced Features
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@section Runtime Message Variation
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Describe @samp{-perform:} and friends.
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@node Forwarding a Message, Adding Methods to a Class, Runtime Message Variation, Advanced Features
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@section Forwarding a Message
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@cindex Forwarding a Message
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Describe @samp{-forward::} and @samp{-performv::}.
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@node Adding Methods to a Class, Posing as a Superclass, Forwarding a Message, Advanced Features
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@section Adding Methods to a Class
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@cindex Categories
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Categories.
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You can use this feature to add new methods to a class, but not to
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change methods that have already been defined in the class implementation.
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You can't add new instance variables (although I should include a
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footnote that shows the hack for getting around this).
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@node Posing as a Superclass, Protocols of Messages, Adding Methods to a Class, Advanced Features
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@section Posing as a Superclass
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@cindex Posing
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Describe @samp{poseAs:}.
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Changing Behavior of Inherited Methods.
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Substituting a your new class for some old class.
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You can use this to override methods that have already been defined in
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the implementation of the old class.
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Use subclassing to override method behavior in new classes you write.
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Use posing to override method behavior in preexisting subclasses of the
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posed class.
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@node Protocols of Messages, Class initialization, Posing as a Superclass, Advanced Features
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@section Defining a Message Protocol
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@cindex Protocols
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@cindex @@protocol
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@node Class initialization, Encoding Types, Protocols of Messages, Advanced Features
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@section Class Initialization
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@cindex @samp{+initialize} method
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Describe the @samp{+initialize} method.
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@node Encoding Types, Structure of an Object, Class initialization, Advanced Features
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@section Encoding Types
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@cindex @@encode
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@node Structure of an Object, Archiving, Encoding Types, Advanced Features
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@section Obtaining the Structure of an Object
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@cindex @@defs
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@node Archiving, , Structure of an Object, Advanced Features
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@section Archiving Objects to a Stream
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@cindex Archiving
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@cindex Typed Stream
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@section ...potential for more here...
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@c ******************************************************************
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@node Builtin Classes, History and Comparisons, Advanced Features, Top
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@chapter Builtin Classes
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@menu
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* The Object Class::
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* The Protocol Class::
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@end menu
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@node The Object Class, The Protocol Class, Builtin Classes, Builtin Classes
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@section The @samp{Object} Class
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@subsection Creating, Copying and Freeing
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@deftypemethod Object {} @keyword{+alloc}
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@end deftypemethod
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@deftypemethod Object {} @keyword{+new}
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@end deftypemethod
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@deftypemethod Object {} @keyword{-init}
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@end deftypemethod
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@deftypemethod Object {} @keyword{-shallowCopy}
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@end deftypemethod
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@deftypemethod Object {} @keyword{-deepCopy}
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@end deftypemethod
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@deftypemethod Object {} @keyword{-deepen}
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@end deftypemethod
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@deftypemethod Object {} @keyword{-copy}
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@end deftypemethod
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@deftypemethod Object {} @keyword{-free}
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@end deftypemethod
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@subsection Identifying the Class
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@deftypemethod Object {(Class*)} @keyword{-class}
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@end deftypemethod
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@deftypemethod Object {(const char *)} @keyword{-name}
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@end deftypemethod
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@subsection Identifying and Comparing the Instance
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@deftypemethod Object {} @keyword{-self}
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@end deftypemethod
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@deftypemethod Object {(int)} @keyword{-hash}
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@end deftypemethod
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@deftypemethod Object {(BOOL)} @keyword{-isEqual:} @var{anObject}
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@end deftypemethod
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@deftypemethod Object {(int)} @keyword{-compare} @var{anObject}
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@end deftypemethod
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@subsection Determining Object Type
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@deftypemethod Object {(BOOL)} @keyword{-isMetaClass}
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@end deftypemethod
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@deftypemethod Object {(BOOL)} @keyword{-isClass}
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@end deftypemethod
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@deftypemethod Object {(BOOL)} @keyword{-isInstance}
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@end deftypemethod
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@subsection Determining Inheritance Relations
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@deftypemethod Object {(BOOL)} @keyword{-isKindOf:} (Class*)@var{aClassObj}
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@end deftypemethod
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@deftypemethod Object {(BOOL)} @keyword{-isKindOfClassNamed:} (const char *)@var{aClassName}
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@end deftypemethod
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@deftypemethod Object {(BOOL)} @keyword{-isMemberOf:} (Class*)@var{aClassObj}
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@end deftypemethod
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@deftypemethod Object {(BOOL)} @keyword{-isMemberOfClassNamed:} (const char *)@var{aClassName}
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@end deftypemethod
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@subsection Determining Messages Understood
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@deftypemethod Object {(BOOL)} @keyword{-instancesRespondTo:} (SEL)@var{aSel}
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@end deftypemethod
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@deftypemethod Object {(BOOL)} @keyword{-respondsTo:} (SEL)@var{aSel}
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@end deftypemethod
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@deftypemethod Object {(BOOL)} @keyword{-conformsTo:} (Protocol*)@var{aProtocolObj}
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@end deftypemethod
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@subsection Method Lookup
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@subsection Sending Messages Determined at Runtime
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@subsection Forwarding
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@subsection Posing
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@subsection Enforcing Intentions
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@subsection Announcing Errors
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@subsection Archiving
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@deftypemethod Object {(int)} @keyword{+version}
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<<Undocumented>>
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@end deftypemethod
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@deftypemethod Object {} @keyword{+setVersion:} (int)@var{aVersion}
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<<Undocumented>>
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@end deftypemethod
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@deftypemethod Object {(int)} @keyword{+streamVersion:} (TypedStream*)@var{aStream}
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<<Undocumented>>
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@end deftypemethod
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@deftypemethod Object {} @keyword{-write:} (TypedStream*)@var{aStream}
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<<Undocumented>> Returns self.
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@end deftypemethod
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@deftypemethod Object {} @keyword{-read:} (TypedStream*)@var{aStream}
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<<Undocumented>> Returns self.
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@end deftypemethod
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@c ******************************************************************
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@node The Protocol Class, , The Object Class, Builtin Classes
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@section The @samp{Protocol} Class
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@deftypemethod Protocol {(const char *)} @keyword{-name}
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@end deftypemethod
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@deftypemethod Protocol {(BOOL)} @keyword{-conformsTo:} (Protocol*)@var{aProtocolObj}
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@end deftypemethod
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@deftypemethod Protocol {(struct objc_method_description *)} @keyword{-descriptionForInstanceMethod:} (SEL)@var{aSel}
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@end deftypemethod
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@deftypemethod Protocol {(struct objc_method_description *)} @keyword{-descriptionForClassMethod:} (SEL)@var{aSel}
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@end deftypemethod
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@c ******************************************************************
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@node History and Comparisons, Runtime Internals, Builtin Classes, Top
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@appendix Objective-C History and Comparisons
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@menu
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* History of ObjC::
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* Smalltalk and ObjC::
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* C++ vs ObjC::
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* Other ObjC's::
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@end menu
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@node History of ObjC, Smalltalk and ObjC, History and Comparisons, History and Comparisons
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@section History of Objective-C
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@node Smalltalk and ObjC, C++ vs ObjC, History of ObjC, History and Comparisons
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@section Smalltalk and Objective-C
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@node C++ vs ObjC, Other ObjC's, Smalltalk and ObjC, History and Comparisons
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@section Difference between Objective-C and C++
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@node Other ObjC's, , C++ vs ObjC, History and Comparisons
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@section Difference between GNU Objective-C and others
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@c ******************************************************************
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@node Runtime Internals, Hacking for Efficiency, History and Comparisons, Top
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@appendix Runtime Internals
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Some notes on topics to be covered:
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Data structures: Symtab, Module, IvarList, MethodList, Category.
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Info bits.
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Runtime class lookup.
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Ivar lookup.
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Method lookup.
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version number.
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IMP.
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objc_class.
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arglist_t.
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sarray.
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@menu
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* Method Lookup and Selectors::
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* Runtime Initialization::
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* Memory Management::
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* Metaclasses::
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* Archiving and Typed Streams::
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* Internal Hash Tables::
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@end menu
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@node Method Lookup and Selectors, Runtime Initialization, Runtime Internals, Runtime Internals
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@section Method Lookup and Selectors
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@cindex Method lookup
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@cindex Selector
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objc_msg_lookup. message to self and super.
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@deftp {Data Type} IMP
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The @code{IMP} data type is a pointer to the function implementing an
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Objective-C method.
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@end deftp
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@node Runtime Initialization, Memory Management, Method Lookup and Selectors, Runtime Internals
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@section Runtime Initialization
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@node Memory Management, Metaclasses, Runtime Initialization, Runtime Internals
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@section Memory Management
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class_create_instance, object_dispose, object_copy...
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|
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For instance, @samp{Object}'s @samp{-alloc} method is implemented like
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this:
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@smallexample
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+ alloc
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@{
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return class_create_instance(self);
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@}
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@end smallexample
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@node Metaclasses, Archiving and Typed Streams, Memory Management, Runtime Internals
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@section Metaclasses
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Move this to "Advanced Features"? I'm not sure we want to talk about it
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as an implementation detail.
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@node Archiving and Typed Streams, Internal Hash Tables, Metaclasses, Runtime Internals
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@section Archiving and Typed Streams
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@cindex Archiving an object to a stream
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@node Internal Hash Tables, , Archiving and Typed Streams, Runtime Internals
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@section Internal Hash Tables
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@c ******************************************************************
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@node Hacking for Efficiency, Debugging ObjC, Runtime Internals, Top
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@appendix Hacking for Efficiency
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@menu
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* Address of a Method::
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* Address of an Ivar::
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@end menu
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@node Address of a Method, Address of an Ivar, Hacking for Efficiency, Hacking for Efficiency
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@section Getting the Address of a Method
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@node Address of an Ivar, , Address of a Method, Hacking for Efficiency
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@section Getting the Address of an Instance Variable
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@c ******************************************************************
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@node Debugging ObjC, Language Summary, Hacking for Efficiency, Top
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@appendix Debugging Objective-C
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|
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@c ******************************************************************
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@node Language Summary, Concept Index, Debugging ObjC, Top
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@appendix Language Summary
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@menu
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* Directives::
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* Declaring Methods::
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* Types and Keywords::
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* Formal Grammar::
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@end menu
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@node Directives, Declaring Methods, Language Summary, Language Summary
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@section Directives
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@itemize @bullet
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@item @@defs
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@item @@encode
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@item @@end
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@item @@implementation
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@item @@interface
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@item @@protocol
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@item @@public
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@item @@selector
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@end itemize
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@node Declaring Methods, Types and Keywords, Directives, Language Summary
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@section Declaring Methods
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Difference between -,+. Return types of methods. Argument types of
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methods.
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@node Types and Keywords, Formal Grammar, Declaring Methods, Language Summary
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@section Types and Keywords
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BOOL, Class, id, IMP, SEL, STR.
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nil, Nil.
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@node Formal Grammar, , Types and Keywords, Language Summary
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@section Formal Grammar of Objective-C
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@c ******************************************************************
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@node Concept Index, Function Index, Language Summary, Top
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@unnumbered Concept Index
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@printindex cp
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@c ******************************************************************
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@node Function Index, , Concept Index, Top
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@unnumbered Function Index
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@printindex fn
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@bye
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