[Zope] Beginner question: user defined variables

[douwe@oberon.nl]

Hi Michael,

>   <dtml-call "REQUEST.set('tot','tot' + charge_amt)">  

What this line says, is to set a variable with the name
'tot' to 'tot'+charge_amt. You probably mean to add
tot (without the quotes) to charge_amt. Zope thinks you
try to add a float to a string and throws the reported
error.

First set 'tot' to 0:
<dtm-call "REQUEST.set('tot',0.0)">

then in the loop add to variable tot:
<dtml-call "REQUEST.set('tot',tot + charge_amt)">  

And you should be all set.

Douwe