"Daniel G. Rusch" wrote:

What is the defintion of (or where can I find one): 1. KeyError 2. AttributeError 3. NameError

Read the documentation available at www.python.org for these Python errors. I believe there are defined in the library reference document. ------------------------------------------------------ Andres Corrada-Emmanuel Email: andres@corrada.com Owner http://www.corrada.com/mamey Mamey Phone: (413) 587-9595 ------------------------------------------------------

Daniel G. Rusch wrote:

What is the defintion of (or where can I find one): 1. KeyError 2. AttributeError 3. NameError

These errors are Python errors. Python raises 'exceptions' when something goes wrong somewhere. Zope catches these exceptions and displays them. For someone familiar with the Zope sources (or when developing an extension in Python) this is very useful, as you can see (in debug mode or in the HTML comments) exactly in what line in what file things went wrong. In many cases however something in the bowels of Zope may go wrong and such an error is raised; the exact Python error message is then not too informative for the end user, unfortunately. That said, an explanation:

1. KeyError

Some code tried to access a dictionary with a key that wasn't in the dictionary. A dictionary is a kind of table/index. For instance, you could have a dictionary in Python like this: dict = { "Martijn" : "Martijn Faassen", "The Other Martijn" : "Martijn Pieters", "Non-Martijn" : "Daniel Rusch" } Then, if the Python code did this: print dict["Martijn"] # or display on a webpage or whatever You'd see this: Martijn Faassen But if you did this: print dict["Parrot"] # Parrot is not in the dictionary! You'd see something like this: ...traceback info... KeyError: Parrot as the 'key' into the dictionary does not exist. This may happen if you're trying to access a REQUEST variable that doesn't exist, for instance, as REQUEST behaves like a dictionary.

2. AttributeError

This happens when Python tries to look inside an object for an attribute that does not exist. This is analogous with a KeyError. For instance, we may have an object with id 'foo' in the object database. Now we want to call method 'manage_doWhatever()' in it, which foo defines: foo.manage_doWhatever() Now we may make a typo in our DTML: foo.manage_doWahtever() Zope will give an AttributeError in that case.

3. NameError

Here Python complains that a name (of a variable, a module, a class or whatnot) does not exist in the current context, for instance: def foo(): i = 0 print i + j 'j' does not exist and Python will complain with a NameError. I hope this helps a bit. Regards, Martijn