On Tuesday 26 November 2002 07:25 pm, Richard A. O'Keefe wrote:
> I've just been reading the book "Pattern Hatching: Design Patterns
> Applied" by John Vlissides, Addison-Wesley 1998, ISBN
> 0-201-43293-5.
>
> I have come away from this with two overwhelming impressions:
>
> (1) Here is a better than competent OO programmer,
>     and C++ is fighting him every inch of the way.

Luckily (?), he's now working mostly on Eclipse plugins (at least 
that's what he told me on the monorail at OOPSLA).

>     Example after example is basically "how do I design-hack a way
>     around such-and-such a limitation of C++."

Yes, but the original Design Patterns book was like that too. There 
are patterns in there that are trivial or unnecessary in Smalltalk.

>     I've always been fairly positive about patterns, and I've
> taught them to students.  This book, by one of the GoF, made me
> wonder. The examples strike me as Heath Robinson-ish; is this
> because of pattern-think, or is it because of C++?

(Note to some US readers: Heath Robinson did drawings similar to Rube 
Goldberg)

Don't you think that (for instance) the C++ template system and 
especially its (excessively?) clever use by the STL rates as a more 
than a bit Heath Robinson-ish? 

>     It would be really illuminating to see some of his examples
>     revisited by a better than competent Smalltalker, because I
>     think you'd end up with a completely different set of patterns
>     being applied, or the patterns would look different.

Or some wouldn't be there, as you note:

>     POOF!  An entire pattern disappears up its own fundament if
> your environment can represent code as data and can run dynamically
> generated code.

Is this something that would be interesting/useful for your students?

"See how patterns only make sense in their original (often unstated) 
context: watch how I make this one go away by a different language 
choice..."

-- 
Ned Konz
http://bike-nomad.com
GPG key ID: BEEA7EFE