Interesting transitions ...

In an early Smalltalk conception, what is now the up arrow was a symbol
that stood for the sender object, i.e. it was a special symbol with a
special meaning (like self), so you were "sending-back" the result.

(And, in the earliest "one-pager" of Smalltalk, sending and receiving were
actually symmetric: one "sentback" the result(s) to the original sender
which could "takeback" and bind the (possibly multiple) result(s).)

Cheers to all,

Alan

----------

At 8:50 PM -0000 3/17/99, Bert Freudenberg wrote:
>Doug Way wrote:
>
>> I guess a better argument for using something other than ^ for returning
>> is that you could then use ^ in place of raisedTo:, e.g. x^2, which is
>> semi-standard typed-math notation.  (When was this introduced?)  Still,
>> it ain't gonna happen. :-)
>
>What's not gonna happen? Using ^ as an operator is as easy as using |
>(there is code in the parser to special-case the vertical bar). The
>attached changeset patches the parser and adds Number>>#^ to give the
>expected result ...
>
>Enjoy :-)
>
>/bert
>
>--
> Bert Freudenberg                                            Department of
>                                                            Simulation and
> mailto:bert at isg.cs.uni-magdeburg.de                     Computer Graphics
> http://isgwww.cs.uni-magdeburg.de/isg/bert.html        Univ. of Magdeburg
>
>Content-Type: TEXT/PLAIN; charset=US-ASCII; name="upArrowOperator-bf.cs"
>Content-ID: <Pine.LNX.3.96.990317215046.28254G at balloon.cs.uni-magdeburg.de>
>Content-Description:
>
>'From Squeak 2.3 of January 14, 1999 on 17 March 1999 at 9:29:05 pm'!
>"Change Set:		upArrowOperator-bf
>Date:			17 March 1999
>Author:			Bert Freudenberg
>
>Makes the upArrow ^ usable as a binary selector. Provides Number>>#^ as
>equivalent to #raisedTo:"!
>
>
>!Parser methodsFor: 'expression types' stamp: 'bf 3/17/1999 20:51'!
>messagePart: level repeat: repeat
>
>	| start receiver selector args precedence words keywordStart |
>	[receiver _ parseNode.
>	(hereType == #keyword and: [level >= 3])
>		ifTrue:
>			[start _ self startOfNextToken.
>			selector _ WriteStream on: (String new: 32).
>			args _ OrderedCollection new.
>			words _ OrderedCollection new.
>			[hereType == #keyword]
>				whileTrue:
>					[keywordStart _ self
>startOfNextToken + requestorOffset.
>					selector nextPutAll: self advance.
>					words addLast: (keywordStart to:
>self endOfLastToken + requestorOffset).
>					self primaryExpression ifFalse:
>[^self expected: 'Argument'].
>					self messagePart: 2 repeat: true.
>					args addLast: parseNode].
>			(Symbol hasInterned: selector contents ifTrue: [
>:sym | selector _ sym])
>				ifFalse: [ selector _ self correctSelector:
>selector contents
>
>	wordIntervals: words
>
>	exprInterval: (start to: self endOfLastToken)
>
>	ifAbort: [ ^ self fail ] ].
>			precedence _ 3]
>		ifFalse: [((hereType == #binary or: [hereType ==
>#verticalBar or: [hereType == #upArrow]])
>				and: [level >= 2])
>				ifTrue:
>					[start _ self startOfNextToken.
>					selector _ self advance asSymbol.
>					self primaryExpression ifFalse:
>[^self expected: 'Argument'].
>					self messagePart: 1 repeat: true.
>					args _ Array with: parseNode.
>					precedence _ 2]
>				ifFalse: [hereType == #word
>						ifTrue:
>							[start _ self
>startOfNextToken.
>							selector _ self
>advance.
>							args _ #().
>							words _
>OrderedCollection with: (start  + requestorOffset to: self endOfLastToken
>+ requestorOffset).
>							(Symbol
>hasInterned: selector ifTrue: [ :sym | selector _ sym])
>								ifFalse: [
>selector _ self correctSelector: selector
>
>				wordIntervals: words
>
>				exprInterval: (start to: self
>endOfLastToken)
>
>				ifAbort: [ ^ self fail ] ].
>							precedence _ 1]
>						ifFalse: [^args notNil]]].
>	parseNode _ MessageNode new
>				receiver: receiver
>				selector: selector
>				arguments: args
>				precedence: precedence
>				from: encoder
>				sourceRange: (start to: self endOfLastToken).
>	repeat]
>		whileTrue: [].
>	^true! !
>
>!Parser methodsFor: 'expression types' stamp: 'bf 3/17/1999 20:52'!
>pattern: fromDoit inContext: ctxt
>	" unarySelector | binarySelector arg | keyword arg {keyword arg} =>
>	{selector, arguments, precedence}."
>
>	| args selector |
>	fromDoit
>		ifTrue:
>			[ctxt == nil
>				ifTrue: [^Array with: #DoIt with: #() with: 1]
>				ifFalse: [^Array
>							with: #DoItIn:
>							with: (Array
>
>	with: (encoder encodeVariable: 'homeContext'))
>
>	with: 3]].
>	hereType == #word
>		ifTrue: [^Array with: self advance asSymbol with: #() with: 1].
>	(hereType == #binary or: [hereType == #verticalBar or: [hereType ==
>#upArrow]])
>		ifTrue:
>			[selector _ self advance asSymbol.
>			args _ Array with: (encoder bindArg: self
>argumentName).
>			^Array with: selector with: args with: 2].
>	hereType == #keyword
>		ifTrue:
>			[selector _ WriteStream on: (String new: 32).
>			args _ OrderedCollection new.
>			[hereType == #keyword]
>				whileTrue:
>					[selector nextPutAll: self advance.
>					args addLast: (encoder bindArg:
>self argumentName)].
>			^Array with: selector contents asSymbol with: args
>with: 3].
>	^self expected: 'Message pattern'! !
>
>!Number methodsFor: 'arithmetic' stamp: 'bf 3/17/1999 20:54'!
>^ aNumber
>	"Answer the receiver raised to aNumber."
>
>	^ self raisedTo: aNumber! !