[Zope3-dev] what is ZCML?

[Shane Hathaway]

Paul Winkler wrote:
> On Mon, Mar 13, 2006 at 04:14:08PM -0700, Shane Hathaway wrote:
> 
>>You're aware of the DRY principle, right?  ZCML is repetitive, and 
>>repetitive is wrong.
> 
> 
> We tend to think that repetition is *always* wrong, but in other fields
> there are cases in which it depends who the reader is, and how the
> repetition is expressed.   One thing I learned in my long-ago days as a
> music student is that the least repetetive way to write a score is often
> the most difficult to sight-read.  The stupidest, most repetitive
> way to write the score is very easy to read; it's completely linear, so
> the reader can't get lost.  You can notate repetition easily enough, and
> make the score more compact, at the expense of requiring the reader to
> mentally construct the linear model and maintain more mental state
> while playing.

In software development, there is an outer surface where you actually do 
want repetition.  In a lot of web projects, for instance, it's perfectly 
fine to write HTML containing scores of repetitive tags.  The right 
choice of what to repeat varies by the project.  The projects I've done 
with Zope 3 have required me to repeat in ZCML even though that choice 
was not appropriate for the projects.

Shane