Forum OpenACS Development: Just noticed something strange happening with acs-templating if tags....

-g

-gustaf neumann

I wonder if it could be a consequence of me creating a custom theme, and not quite getting the set-up quite right. This is the first time I have done it, so I may have messed it up.

R.

The conditionals that are coming through to the browser are those that I have nested within a <property> tag.  I've tried to do something like this (simplified as example):

<property name="wikicmds">
  <div id="wikicmds">
    <if @admin_link@ not nil>
      <a href='@admin_link@'>Admin</a>
    </if>
  </div>
</property>

If I modify the above to this for diagnostic purposes:

<property name="wikicmds">TEST</property>
<div id="wikicmds">
  <if @admin_link@ not nil>
    <a href='@admin_link@'>Admin</a>
  </if>
</div>

....then the if statements no longer come through to the browser.

I need to do this in order to get the wikicmds up into the master template, because I want them to be children of an element that is within the master template.  This is to achieve robust and reliable positioning using CSS.

I was not aware of this limitation.  Is this indeed the case, that acs-templating is not designed to evaluate <if> tags that are enclosed within <property> tags?

Logically, I would expect the <if> statements to be evaluated first, to construct the property string to pass up.  I would not expect the conditional to be passed up for evaluation in the variable context of the receiving master template.

Any suggestions for a workaround, or comments on this behaviour would be much appreciated.

Regards
Richard

Fantastic, thank you. I am not familiar with the acs-templating code so that is fabulously helpful.

I'll add that and report back.

Regards
R.

For example, if you test with this in the xowiki template:

<property name="wikicmds">||<div id="test">TEST</div>||</property>

...and this in the plain-master.adp:

<if @wikicmds@ not nil>
  CONTENTHERE:@wikicmds@:CONTENTHERE
</if>

The result in the browser source is:

CONTENTHERE:||&lt;div id=&quot;test&quot;&gt;TEST&lt;/div&gt;||:CONTENTHERE

Regards
Richard

<property name="wikicmds">
  <div id="test">
    TEST
  </div>
</property>

Then I get the expected result in the document source:

<div id="test">TEST</div>

But as soon as I introduce an <if> tag:

<property name="wikicmds">
  <div id="test">
    <if @index_link@ not nil>
      TEST
    </if>
  </div>
</property>

...then what I get is this:

</div>

Yes, that's just a single closing tag without the corresponding opening div tag.

Regards
Richard

Thank you for the follow-up, and for the suggestion of falling back to the lower level solution.

It occurs to me that whilst you clearly cannot nest <if> tags inside a <property> tag, you can of course put <property> tags inside an <if> tag! 😊

I have therefore re-ordered my template to conditionally populate a property for each of the wikicmds, and to pass these properties separately up to the master template.  The master template will display these if they are not nil and will wrap them in their containing <div>.  This seems to work just fine.

The advantage is that this works without any modification to acs-templating.  The disadvantage is that it requires xowiki specific modification to my plain-master.adp, however this is in a custom theme package anyway, so not really a problem.

Whilst doing this I discovered something else I didn't know, which is that property names cannot contain a hyphen! Is that widely known?

If I pass up and test for <property name="wikicmds_index"> everything works as expected.  However, if I use <property name ="wikicmds-index"> I get an error message inserted into the page which reads:

IF tag nil test uses string not variable for "@wikicmds-index@"

I wonder if that is a feature or a bug?

Regards & many thanks,
Richard

SInce the template is only parsed once, you can parse the if tags then the outer property tags. Its all parsed into one tcl script.

You could modify the property tag tcl to accept code within (such as the multiple tag etc.) but it seems overly complicated. Just evaluate what you need in the tcl script and generate the HTML there.