[Zope] Getting error assigning sequence-item to REQUEST

[Jim Washington]

Hi, Richard

What you want is:

<dtml-call expr="REQUEST.set('tune_name',_['sequence-item'])">

but read further.  There is another solution, too.

Anything you do in ""quotes  within a DTML tag is interpreted as a
python expression.
The way you wrote it , zope tried to evaluate the expression
'sequence-item' as 
"sequence minus item", and failed it because it could not find reference
to the variable 'sequence'.

One workaround is to gather the object from the '_' namespace. 
_['avariable'] gets the first thing named avariable, so
_['sequence-item'] gets the current sequence-item, which is the above
"quickie" answer.

But what most of us do (sequence-item being a legacy in DTML from before
expressions were allowed IIRC, so it would break a lot of existing code
to rename it) is use a 'dtml-let' tag immediately after the 'dtml-in'
tag.

e.g.,
<dtml-in "_.string.split(tune_names,'|'")>
<dtml-let currenttune=sequence-item>
   ...do something with currenttune...
</dtml-let>
</dtml-in>

Using a 'dtml-let' allows you to use exactly the same syntax that you
really wanted to use before, but now you have a handle to the thing you
are working with, and it is evaluated as what you want, not a
subtraction.

hth.

-- Jim Washington


Richard Moon wrote:
> 
> Can anyone tell me why the following
> <dtml-in "_.string.split(tune_name,'|')">
>      <dtml-if sequence-start>
>        <dtml-call expr="REQUEST.set('tune_name',sequence-item)">
> 
> raises the error "Error Type: Name Error  Error Value:sequence"
> 
> It is the last line which raises the error.
> 
> This is the error I would expect if I was trying to use a variable which
> wasn't in the current namespace so I am confused why I cannot use
> sequence-item in this way.
> 
> Can anyone tell me the correct syntax (and why ) ?
> 
> Thanks in advance
> 
> Richard
> 
> Richard Moon
> richard@dcs.co.uk