[Zope-dev] Curious problem with comprehensions and PythonScripts

[Steve Alexander]

Here's the situation:

I have a dtml document with a list of questions under various headings, 
formatted like this:

HEADING 1
   question1
   question2
   question3

HEADING 2
   question 4
   question 5


I have a PythonScript that gives a list of only the questions to a Page 
Template:

PythonScript called get_questions:

data=container.data_document(None, None)

# ignore blank lines
# lines with no leading space are headings
# lines with leading space are questions

return [l for l in comps.splitlines()
           if l
           if l[0] is ' ']

I'm rendering this using a page template:

<td tal:repeat="question container/get_questions">


The problem is, I'm often (always?) getting no questions rendered.

However, if I change the python script to this, it works every time.

PythonScript called get_questions:

data=container.data_document(None, None)

# ignore blank lines
# lines with no leading space are headings
# lines with leading space are questions

questions = [l for l in comps.splitlines()
                if l
                if l[0] is ' ']

return questions



Any ideas what might be happening?

I think the compiled code of the python script might be incorrect when 
directly returning the results a comprehension.

--
Steve Alexander
Software Engineer
Cat-Box limited