On 8/26/07, Bert Freudenberg <bert at freudenbergs.de> wrote:
> On Aug 26, 2007, at 11:01 , Fabio Filasieno wrote:
>
> > collection := OrderedCollection new.
> > collection add:1.
> >
> > evaluates to one. Why ? Why not to collection ?
>
> You do not always add a simple value but the result of an expression.
> Having the #add: return the argument sometimes lets you avoid
> introducing a temporary variable. It is more useful this way, and for
> the cases where you actually want the collection you can use a cascade.
>
> A similar point can be made that setters should return the argument
> instead of the receiver, although usually in Squeak they do not
> (Tweak revises that policy).
>
> - Bert -

+1, exactly.  By returning the argument you have more options then if
you return self.  You could do something like:

addToJohn: aSalary andFred: anotherSalary
self totalSalary: (john addToSalary: aSalary) + (fred addToSalary:
anotherSalary)

If all those setters return self then this takes several more
statements.  And there is no need to return self, as it is already
accessible via cascade (as Bert pointed out).