[Shane]
Are you sure ZCML is The Right Way?  I know its purpose (since I helped
invent Zope 3): to combine configurations by multiple developers without
imposing a particular workflow.  However, I maintain that Python code could
do the job better.  The Python code I have in mind is not the same as
Jeffrey's examples.  I'll elaborate if there's interest.


[Pete Taylor]
> *ping* for interest in elaboration on the code you have in mind...

Ok.  Here are two snippets that express the same thing.  First in ZCML:

  <browser:skin
      name="Rotterdam"
      interface="zope.app.rotterdam.Rotterdam" />

  <browser:resource
      name="zope3.css"
      file="zope3.css"
      layer="zope.app.rotterdam.rotterdam" />

Now in Python (hypothetical):

    from zope.app import rotterdam

    def configure(context):
        context.browser.skin(
            name='Rotterdam',
            interface=rotterdam.Rotterdam)
        context.browser.resource(
            name='zope3.css',
            file='zope3.css',
            layer=rotterdam.rotterdam)

All functionality and capabilities of ZCML are retained, but there are important, subtle differences.

- I could conceivably type configuration directives at the interactive Python prompt. I could use the standard dir() and help() functions to find out what directives exist and how to use them.

- If I want to register a lot of similar things, in ZCML I have to either repeat myself, leading to poor maintainability, or create new directives, leading to directive proliferation. In Python I can use variables, loops, functions, etc., reusing skills I already know.

- If I want to debug a registration, I can use pdb or any other Python debugging tool.

- Code snippets can include both the code and the default configuration (yet users are not forced to use the configuration), making code samples clearer.

Those are the technical arguments. There is also the marketing argument that a lot of the target audience has been burned by XML, but I don't think that's the right basis for making a decision. I sincerely believe Python code would be better than XML for the technical reasons I listed above.

Shane
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