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From: new@udel.edu (Darren New)
Newsgroups: comp.lang.smalltalk
Subject: Re: Question on Ordered Collections
Message-ID: <10271@nigel.udel.EDU>
Date: 6 Feb 90 13:22:56 GMT
References: <1045@prlhp1.prl.philips.co.uk>
Sender: usenet@udel.EDU
Reply-To: new@udel.edu (Darren New)
Distribution: comp.lang.smalltalk
Organization: University of Delaware
Lines: 31

In article <1045@prlhp1.prl.philips.co.uk> krause@prlhp1.UUCP () writes:
@    Fred <- OrderedCollection new
@        add: 'anItem';
@        add: 'anOtherItem';
@        add: 'finalItem'
@Fred will NOT be an ordered collection, but a string.

The value assigned to Fred is the value returned from the final add: message.
If you examine add:, you will see that it returns its argument, not self.

@    Fred <- OrderedCollection new
@       add: 'anItem';
@       add: 'anOtherItem';
@       add: 'finalItem';
@       yourself
@Will result in Fred becoming an ordered collection. 

yourself, not containing a return, defaults to returning self. Thus,
the new OrderedCollection is returned and assigned to Fred.

@    Fred <- OrderedCollection new.
@    Fred add: 'anItem';
@       add: 'anOtherItem';
@       add: 'finalItem'

Here, you ignore the vale returned from the add: call and get what you
expect.  I think it is believed that the argument to add: is more often
needed after adding than the Collection is; hence, add: returns its argument.
This kind of stuff is often a gotcha and IMHO makes Smalltalk harder
to master (but of course more flexible).   Happy Hacking!
		  Darren