On 12/30/05, Jeff Shell <[EMAIL PROTECTED]> wrote: > - the TAL namespace had a limited and proper list of attributes. A > very limited set of names that could be (theoretically) validated with > standard XML tools.
This should probably remain a goal, but I don't think it's as big a deal as the ordering problem. > - XML processing, if I recall correctly, does not cover ordering of > tag attributes, nor gives them any significance. You couldn't have > 'attr:title' have any dependency on 'attr:href', for example. That's correct; attributes do not have order in the XML information set. > As a result, there are a limited list of TAL keywords with a well > defined order of execution. > > How would these namespaces impact that? When doing "proper" XML > processing with TAL, would the 'attr' and 'defines' and other > namespaces all need to be explicitly loaded? We could easily say that each of these namespaces is processed at a certain point in the evaluation order; that's easy. Defining the order of processing within any one of these namespaces could be done on a strictly arbitrary basis ("sorted by attribute name", for example), but remains arbitrary. This would lead to unsavory practices, like naming defines to control the order of evaluation rather than to express what's stored in them. I can't speak for others, but order of evaluation is often important when I have more than one define on a single element. The only example namespace I can think of that behaves this way is the xmlns: namespace, and that's also special in that the prefix is frozen. It's dealing with a chicken-and-egg problem, which we don't need to do. > More namespaces increases the chance of namespace > collision. I'm not sure what this means; use whatever prefixes you want. All this said, I understand Alex's desire to avoid long piles of stuff in attribute values; it's not very common to have several lines of stuff in an attribute. In most situations where substantial text is needed in an attribute, the attribute value is a reference (often via URL) to some other resource. But for what we're doing in TAL, that doesn't make much sense: the template becomes harder to understand and maintain, and the volumn of text is unlikely to be more than a handful of lines. I'm glad he's thinking about how we can improve the situation. -Fred -- Fred L. Drake, Jr. <fdrake at gmail.com> "There is no wealth but life." --John Ruskin _______________________________________________ Zope3-dev mailing list Zope3email@example.com Unsub: http://mail.zope.org/mailman/options/zope3-dev/archive%40mail-archive.com