[Zope] dtml-let + dtml-in question

[A. B. Monta]

1. I'm using DTML to declare some new names in the
namespace and do 
simple math, thus:

<dtml-let subtotal_hotel_rate1="_.float(hotel_rate1) *
_.int
(hotel_rate1_days)">

2.  I want to display these subtotals if, say,
"hotel_rate1" has a 
non-null value.  No problem there (at least not any
more thanks to Alexis and Ted!).  

3.  However, I then want to sum only the subtotals
that get to be 
displayed.  What's the best way of doing this?  I'm
stuck because to 
display the subtotals, I've had to close out the
dtml-let tags that 
enabled them to be displayed in the first place.

Furthermore, I can't make the calculation of the total
conditional on 
there being just one non-null value.  This would not
do, for ex:

<dtml-if hotel_rate1>
[calculate some total]
</dtml-if>

because there might be a non-null value for
hotel_rate2 (there are 5 
hotel rates total), which has to be accounted for.  I
have to calculate all the subtotals and 
include them in the mix for the total calculation.

I've thought about looping in the value of *any*
namespace variable 
that begins with the string "subtotal_".  I'd have to
convert those 
strings to floating-point integers before doing the
math.  That 
approach sounds reasonable to me, but I don't know how
construct the 
dtml-in syntax in this case.

Any pointers/redirections/examples are greatly
appreciated.

Cheers,
Anthony


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