Brian van den Broek wrote:
<SNIP Kent's useful explanation of how to use handlers>
Also, I know the general security concerns about things like exec. They make me nervous in using it, even though I am (as yet) the sole user. Am I right in thinking that the constrained way I am using it here protects me? My code uses most of the attributes as a simple storage container for later rewriting of the file, but in a few cases they enter into (safe seeming) conditionals like:
if 'text' == self.document_type: self.do_text_stuff() if 'RTF' == self.document_type: self.do_RTF_stuff()
Conditionals on a 'type' flag are a code smell that suggests using subclasses. Maybe you should have a TextNode class and an RtfNode class. Then the above becomes just
self.do_stuff()
and TextNode and RtfNode each have the appropriate implementations of do_stuff().
I'm not saying this is the right choice for you, just something you might consider.
Kent
Hi Kent,
thanks for the snipped discussion on handlers -- very useful.
As for the code smell thing, I have a follow-up question. I now get the point of the type-based conditional being a smell for classes. (I get it due to a previous thread that an over-enthusiastic inbox purge prevents me from citing with certainty, but I think it was Bill and Alan who clarified it for me.)
My problem is that I've got a lot of code which was written before I got that point and my code doesn't yet actually do much. (I do have working code for parsing my original source files and storing all of their metadata, etc., but I haven't yet got working code for doing the manipulating the data in the ways I want.)
I had been thinking better to get everything working and then refactor. Is that an unsound approach? My worry about refactoring now is that I feel like I am rearranging deck-chairs when I should be worried about getting the ship to float :-)
Thanks and best to all,
Brian vdB
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