Re: [Help-smalltalk] iliad and blocks

[Paolo Bonzini]

>> Joachim builds a PageTemplate widget, and I'm not sure I like the idea
>> of returning blocks from the methods there (like #mainContent).
>
> Why don't you like it? I think blocks are expressive and less verbose
> here.

They *are* good as a shortcut, especially since you cannot afford an
extra argument to the view messages (like #indexOn: -- that would be
ugly!).

I just don't think that using #value: as "the" protocol for rendering
is clean, because it makes it harder to return some other object in a
polymorphic way (for example a widget itself).  If everything has
to implement #value: sooner or later you run into conflicts, or into
something that expects more protocol from BlockClosure.

It just leads to hacks like the infamous Symbol>>value: method.  If it
was me, I would not even call #value: from
#select:/#reject:/#collect:.  I would use two methods, one for
#select:/#reject: and one for #collect:, and then implement those on
Symbol, Regex, and whatever else.  This would allow things like:

    'paolo' select: #($a $e $i $o $u $y) -> 'aoo'
    #('paolo' 'bar' 'baz') collect: '(.a)[oz]' -> #('pa' nil 'ba')
    #('paolo' 'bar' 'baz') select: 'a..' asRegex -> #('paolo')

(Of course, finding good names for the methods would be another thing.
 That's why the above idea is not in GNU Smalltalk yet...).

Paolo