I agree that the symmetry in the solution is a must else we would  
have really strange behavior (like the ones you mentioned).
I was wondering what is the advantage to have strings and symbols  
been equals. I still do not understand deeply the pros and the
cons of each approach. This is true that we could consider that a  
symbol is a special string (unique) but I wonder what are the in
terface incompatibility. My question is if today I would have to  
design a library would I make the difference or not. And I'm puzzled.

Stef


On 12 août 07, at 21:21, Andreas Raab wrote:

> stephane ducasse wrote:
>> But I'm confused do you imply that the order in which the elements  
>> were added had an impact on the set?
>
> Yes.

I agree indeed it is quite important.
>
>> in VisualWorks
>
> Well, but in VisualWorks also:
>
> String>>= aString
> 	"Answer whether the argument is a string, and is not a symbol,
> 	and the receiver's size is the same as aString's size, and each of  
> the receiver's
> 	elements equal the corresponding element of aString"
>
> 	| size |
> 	aString isString ifFalse: [^false].
> 	aString isSymbol ifTrue: [^false].
> 	(size := self size) = aString size ifFalse: [^false].
> 	1 to: size do:[:index | (self at: index) = (aString at: index)  
> ifFalse: [^false]].
> 	^true
>
> So in other words, in VisualWorks Strings and Symbols always  
> compare false which is perfectly symmetric.
>
> Cheers,
>   - Andreas
>
>