[Zope] dtml-in strange behavour?

[J Cameron Cooper]

mettwoch at pt.lu wrote:
> Hi,
> 
> Could someone explain why iterating over a list of lists, like this:
> 
> <dtml-in expr="[[1,1],[2,2]]">
>   <dtml-var sequence-item><br>
> </dtml-in>
> 
> gives as result:
> [1,1]
> [2,2]
> 
> but iterating over a list of tuples like this:
> 
> <dtml-in expr="[(1,3),(2,4)]">
>   <dtml-var sequence-item><br>
> </dtml-in> 
> 
> gives as result
> 3
> 4
> 
> A list of tuples is created for instance when applying the items() method on a dictionary resulting from a SQL method call.
> 
> When doing the above iterations in Python console, it gives the expected result eg. two lists and two tuples.

DTML breaks that up in sequence-item and sequence-key. From Zope online 
help for dtml-in:

"""
Tag Variables
Current Item Variables

These variables describe the current item.

sequence-item
     The current item.
sequence-key
     The current key. When looping over tuples of the form (key,value), 
the in tag interprets them as (sequence-key, sequence-item).
"""

I can't really say why, though.

		--jcc