Ugo Cei wrote:
Dear Cocooners,
while working on Butterfly, I started looking at the TreeProcessor and I was astonished at the number of classes I have to port, if I want to reimplement it:
o.a.c.components.treeprocessor: 26 classes o.a.c.components.treeprocessor.sitemap: 44 classes o.a.c.components.treeprocessor.variables: 4 classes Total: 74 classes.
Some of these classes have a rather complex inheritance hierarchy. Just to pick one at random: PreparableMatchNode inherits (directly and indirectly) from 6 classes and 10 interfaces!
Now this is a lot of code. Kudos to Sylvain for coming up with it and I'm sure the design is the best possible, given the constraints. But since, in doing Butterfly, I determined that we should not be too constrained by backward compatibility, I started thinking about a possible alternative, which should be, first of all, much simpler.
One thing that we would probably like to do without is the pointy-brackets kind of sitemap syntax. We could define a friendlier syntax of our own devising or we could reuse something. Since I'm a lazy butt and I like to reuse others' code whenever possible, I decided to reuse an existing grammar and parser. And I wanted it to be an executable grammar, that is a scripting language, since I wanted to avoid writing the code to execute a data structure. Last, I wanted to use something trendy ;-) so I came up with "A Groovy Kind of Sitemap" (sorry, Phil):
if (match ".*\.html") { generate "input.xml" transform "xslt", "stylesheet1.xsl" transform "xslt", "stylesheet2.xsl" serialize "xml" }
I have to admit I'm ashamed at how bad and simpleminded the implementation of this is (you can find it in Butterfly's CVS). And propbably using a full-fledged scripting language isn't such a good idea (I already see people putting database access code in the sitemap), but it took no more than two hours to implement (one and half spent trying to make sense of Groovy's scattered docs), so it's definitely simple.
Implementation details aside, I think this is something that we can experiment with. I propose to adopt a pragmatic approach: do not try to design the best possible sitemap syntax, but instead use what is readily available (Groovy) and try to push it to the limits. If it breaks before it's actually useful, we'll think of something else.
Sinful as it might sound, I had been thinking about a non-XML syntax for the sitemap for a long time ;-)
Now, if you want to have me completely happy, add the abilityt to run java as it was a scripting language (no need for recompilation and start/stop the container)
[chris already wrote the code for that, it's just a matter of integrating it inside the core]
-- Stefano.
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