[Zope] <dtml-call >

[Jeff Hoffman]

On Fri, 3 Mar 2000, Chui Tey wrote:

> Hi,
> 
> What is the difference between <dtml-call "...."> and <dtml-call ...>.  For
> instance, if I have this directory structure:

[snip]

> <dtml-call subfolder.manage_addFolder(...)> doesn't add any folders, while
> <dtml-call "subfolder.manage_addFolder(...)"> behaves as expected. It took
> about an hour of experimenting before getting this right. Could someone
> explain what is the difference here?

Calling tags with and without quotes follows mostly the same convention
throughout Zope. A tag without quotes, such as:

  <dtml-var myMethod>

is equivalent to:

  <dtml-var name=myMethod>

This says, "Include the variable with the name myMethod." The alternate
form is:

  <dtml-var "myMethod()">

which is equivalent to:

<dtml-var expr="myMethod()">

This says, "Include the result of the Python expression in quotes,
myMethod()."

In your specific case, dtml-call without quotes is equivalent to
using the name form, and thus does nothing. There is no attribute or
method called subfolder.manage_addFolder(...). Note that Zope would be
looking for this, literally, and would not interpret the period as an
application of a method to an instance.

Using the dtml-call tag with quotes is equivalent to the expr form, and
will thus interpret the period appropriately.

To convince yourself that this is the case, try including a DTML Method
using the expr form without parenthesis:

  <dtml-var expr="myMethod">

puts this in the response:

  <function myMethod at 8071cf8>

If you view this in a browser, you will not see it because your browser
will try and interpret it as a <function ...> tag, which, of course, does
not exist.

> Thanks.

Hope this helps.

> Chui

--Jeff

---
Jeff K. Hoffman                                         704.849.0731 x108
Chief Technology Officer                                mailto:jeff@goingv.com
Going Virtual, L.L.C.                                   http://www.goingv.com/

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