Ognen Duzlevski wrote: > Larry Bates <[EMAIL PROTECTED]> wrote: >>> Now I want to use something like xml.dom.minidom to "parse" the >>> .xml file into a set of classes defined according to the "language >>> definition" file. The parse() method from the xml.dom.minidom >>> package will return a document instance and I can get the node >>> name from it. Say I got "page" as a string. How do I go about >>> instantiating a class from this piece of information? To make it >>> more obvious how do I create the page() class based on the "page" >>> string I have? I want to make this generic so for me the language >>> definition file will contain pages, functions, datasets etc. but >>> for someone else mileage will vary. >>> >>> Thanks, >>> Ognen > >> I think you should rethink this approach. Why have 3 different >> files instead of just defining everything as Python classes? >> Get good baseclass definitions and use OOP inheritance to >> create your specific class instances. I think mixing XML, >> language definition file (LDF), LDF to python parser is a LOT >> harder (and slower) than just writing the classes outright. > > Hi Larry, > > here is the whole story. I have a database (postgres) xml "transformer" > and substitution engine. It is written entirely in plpgsql and the whole > environment works something like this. Someone writes an xml file that > defines a web page. This xml file is then fed into the database at the > time of development. Now at runtime a mod_python apache webapp makes a > request for a certain page. Its xml form is retrieved from the database > and a lot of data substitution goes on. Also parts of the page are "masked" > out by the database engine based on the "level" of the person requesting > the page. The "transformed and substituted" xml is then spit back to the > webapp which now applies an xml->html transformation and presents the > final result to the user. So, I want people to be able to "define" their > own "language" when it comes to page definitions. And instead of rewriting > the xml file parser I want to be able to generate the parser. > > Thanks, > Ognen
Well you certainly can do that, but why invent a new language to define the pages instead of just using Python directly? I did an application a few years ago that sounds a little like what you describe and now wish I had not spent so much time doing Text File->Python transforma- tions. The logic got pretty ugly and extending things was rather involved. It wasn't until I started using ReportLab that I began to "see the light" on just keeping everything in Python and inheriting from base classes and extending. If you want to define a Python class, the best way to do that is to use Python from the outset. I probably don't completely understand what you want to do, but thought I'd at least put in my 2-cents worth. Regards, Larry -- http://mail.python.org/mailman/listinfo/python-list
