AW: where to put handlers?
devin_asay at byu.edu
Wed Feb 6 10:05:16 CST 2008
On Feb 6, 2008, at 2:06 AM, Tiemo Hollmann TB wrote:
> Hi Mark,
> Interesting to read that totally opposite approaches are both
>> A lot of projects that are sent to me are unnecessarily complex
>> because people try to be "smart", putting handlers in weird places.
> Btw. I go the same way as Sadhu and feel comfortable with my way,
> in maintenance cases, where I don't have to think about where a
> could be placed. In smaller projects my "weird place" for almost all
> handlers is the stack script. I do actually have only one single
> handler in stack script, with cases of targets. So I uncoupled
> logic from
> design, what has advantages and disadvantages. I don't know, if and
> how my
> approach would work in bigger projects, but up to now, its good for
I have two objections to placing all handlers high in the message
1. It destroys the modularity/object-oriented-ish-ness of Revolution
stacks. If I create a particularly brilliant object (or at least a
complicated object that is "good enough") I often want to re-use it
in other projects. If I've separated the scripting from the objects
it becomes much more difficult.
2. As a project grows in complexity, a stack script that contained
all handlers in the stack could easily swell to several thousand
lines. In this case it actually becomes *harder* to maintain, as you
must scroll or search through a huge script to find the handler
you're looking for. It even becomes difficult to find a handler in
the handler list of the script editor as the number of handlers
multiplies. I once inherited an extremely complex project in which
the original programmer had used the approach of placing all
scripting in the stack script. While the handlers were well-written
and well-documented, and the stack worked pretty well, I had a devil
of a time figuring out which handlers did what, and to which objects
they related. After several months I *started* to get the hang of it,
but I lost a lot of time figuring it out.
I like Jerry Daniels' axiom: Put handlers as high as they need to be
in the hierarchy, but no higher.
Humanities Technology and Research Support Center
Brigham Young University
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