On Friday 2008.12.05, at 12:33 , Terence Parr wrote: [...] >> In addition to just querying attributes from the context, you can >> also pass parameters to (query) functions. And this is mandatory in >> our case. Our input data is XML and the templates emit portions from >> the XML by referring to XML nodes through XPATH. So in a template >> you might find something like >> >> DoIt() first parameter: <%= Value( "//[EMAIL PROTECTED]'DoIt']/ >> Parameters[0]" ) %>. >> >> Where Value( string xpathExpr ) is such a query operation to get the >> referenced data from the XML. The problem is that we have a lot of >> templates that all need different data portions so hardcoding those >> queries in form of getters is not an option. >> >> Can ST do this as well? > > Well, it depends on what the arguments are. if it's an attribute or > string of some kind, you can use the format option and a renderer. > > Any time I need to pass an argument back into the model from the > template, I ask myself whether I am allowing the model to leak into > the template. If it looks the program, it probably is. That is not > something you want to happen to your template. In your case, It's hard > to tell. But, xpath stuff to pull specific nodes from a data structure > makes me a bit nervous unless you are just descending through the > various nodes. One could argue that the template should simply be > displaying data, not encoding how to jump around and ask about tree. > One test is to ask whether or not you could use that template with > another data structure. just something to think about.
In addition to Ter's very good points, I can add that in terms of the XML'ish nature of this question that switching from a hacked template approach to using XQuery is a very good option. I.e., processing XML and generating X(HT)ML is much more "natural" and easier using XQuery than trying to deal with the latest (weirdo :-) JSP/ASP/etc. abomination. To be clear, I still like the enforced separation of the ST approach in general but for a lot of XML hacking, XQuery allows for the relatively controlled intermingling of processing, structure, and hacking that seems to be very prevalent in XML processing (think: multi-stage pipelines that aren't clearly thought of as pipelines). We use XQuery on the backend of http://markmail.org/ and it generates XHTML, JSON, RSS, etc. for the various types of data streams. Hope this helps, John List: http://www.antlr.org:8080/mailman/listinfo/antlr-interest Unsubscribe: http://www.antlr.org:8080/mailman/options/antlr-interest/your-email-address --~--~---------~--~----~------------~-------~--~----~ You received this message because you are subscribed to the Google Groups "il-antlr-interest" group. To post to this group, send email to il-antlr-interest@googlegroups.com To unsubscribe from this group, send email to [EMAIL PROTECTED] For more options, visit this group at http://groups.google.com/group/il-antlr-interest?hl=en -~----------~----~----~----~------~----~------~--~---
