From: Kevin Smith <kevinbsmith@...>
Date: 2001-11-03T01:16:53+09:00
Subject: [ruby-talk:24172] Re: Modularity question (and XP)

--- "Hal E. Fulton" <hal9000@hypermetrics.com> wrote:
> The "Big Design" syndrome is real, but the opposite
> extreme is excessive sloppiness and failure to plan 
> ahead.
> 
> I think of it as "prefactoring" -- as far as I know, I
> made up that word. No charge for that.
> 
> I'm not talking about a gigantic productivity
> improvement, of course...
> I'm talking in the realm of "an hour of prefactoring is
> worth two hours of refactoring."

My own experience with XP leads me to believe that "one
hour of refactoring is worth at least two hours of
prefactoring".

One of the XP practices that "enforces" modularity is TFD
(test first design). It's a powerful way to work, but does
require quite a bit of commitment, and it feels very
strange at first. Many people who try it, however, never go
back to the "old way".

In the specific case you mentioned, I would be inclined to
look for "reasonable" boundaries between your app and the
specific db and gui packages you choose for your initial
implementations. Later, when you go to add a different db
or gui, refactor as needed.

It's really hard to predict how a generic interface should
be designed. It's much easier to mold an existing specific
interface into a generic one. [Assuming your code is
simple, well-factored, and ideally has unit tests].

Kevin


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