"

 COPYRIGHT (c) 1988 by Claus Gittinger

	      All Rights Reserved

 This software is furnished under a license and may be used

 only in accordance with the terms of that license and with the

 inclusion of the above copyright notice.   This software may not

 be provided or otherwise made available to, or used by, any

 other person.  No title to or ownership of the software is

 hereby transferred.

"

Object subclass:#Message

       instanceVariableNames:'selector args'

       classVariableNames:''

       poolDictionaries:''

       category:'Kernel-Methods'

!

!Message class methodsFor:'documentation'!

copyright

"

 COPYRIGHT (c) 1988 by Claus Gittinger

	      All Rights Reserved

 This software is furnished under a license and may be used

 only in accordance with the terms of that license and with the

 inclusion of the above copyright notice.   This software may not

 be provided or otherwise made available to, or used by, any

 other person.  No title to or ownership of the software is

 hereby transferred.

"

!

version

!

documentation

"

    Instances of Message are only created, when a message send fails 

    (i.e. some message is not understood).

    In this case, the selector and arguments are put into an instance of 

    Message, which is then passed to #doesNotUnderstand: as argument.

    Typically, Object>>doesNotUnderstand: is evaluated, which starts up

    a debugger, but it is possible to redefine this method, which

    allows for re-evaluation of the failed send (after some cleanup).

    As an example of its use, see the implementation of the Autoload-class,

    or how ScrollableView forwards unknown messages to its slave-view.

    Notice:

    Since the layout of Message-objects is known by the runtime system, it is 

    not allowed to change the definition of this class.

"

! !

!Message class methodsFor:'instance creation'!

selector:aSymbol

    "return a new message object for a send without arguments"

    ^ self basicNew setSelector:aSymbol arguments:nil

!

selector:aSymbol with:anArg

    "return a new message object for a send with one argument.

     OBSOLETE: use #selector:argument: for ST-80 compatibility."

    ^ self basicNew setSelector:aSymbol arguments:(Array with:anArg)

!

selector:aSymbol with:arg1 with:arg2

    "return a new message object for a send with two arguments.

     OBSOLETE: use #selector:arguments: for ST-80 compatibility."

    ^ self basicNew setSelector:aSymbol arguments:(Array with:arg1 with:arg2)

!

selector:aSymbol withAll:argArray

    "return a new message object for a send with many arguments.

     OBSOLETE: use #selector:arguments: for ST-80 compatibilty."

    ^ self basicNew setSelector:aSymbol arguments:argArray

!

selector:aSymbol argument:anArg

    "return a new message object for a send with one argument"

    ^ self basicNew setSelector:aSymbol arguments:(Array with:anArg)

!

selector:aSymbol arguments:argArray

    "return a new message object for a send with many arguments"

    ^ self basicNew setSelector:aSymbol arguments:argArray

! !

!Message class methodsFor:'queries'!

isBuiltInClass

    "this class is known by the run-time-system"

    ^ self == Message

! !

!Message methodsFor:'private accessing'!

setSelector:aSymbol arguments:argArray

    "set selector and arguments of the receiver"

    selector := aSymbol.

    args := argArray

! !

!Message methodsFor:'sending'!

sendTo:aReceiver

    "send the selector with argument to some receiver"

    ^ aReceiver perform:selector withArguments:args

!

reinvokeFor:aReceiver

    "send the selector with argument to a receiver.

     Same as sendTo: - for GNU-ST compatibility."

    ^ self sendTo:aReceiver

! !

!Message methodsFor:'accessing'!

selector

    "return the selector of the message"

    ^ selector

!

arguments

    "return the arguments of the message"

    ^ args

! !

!Message methodsFor:'printing & storing'!

displayString

    "return a string for display in inspectors etc."

    ^ 'Message(' , selector , ')'

!

printOn:aStream

    "return a string for printing the receiver"

    selector printOn:aStream

! !