Forum OpenACS Development: conditional property

I have 2 different items that I may or may not want to put in the <property name="header_stuff"> tag at the top of an ADP page. Each of the items should be present only if a certain condition is true.

I tried the obvious first:

<property name="header_stuff">
<if @condition_1@>Item 1</if>
<if @condition_2@>Item 2</if>
</property>

Unfortunately, that doesn't work since ADP tags aren't evaluated inside a <property> tag, they're just spit out to the page.

So I could either

1. Make 4 different <property> tags and then do a complex set of if/then's to decide which one to output.
2. Do the evaluation in the tcl page and have a simple <property name="header_stuff">@item_1@@item2@</property> tag, but this would mean putting HTML markup in the TCL file.
3. Maybe there's a third way I'm not thinking of?

To see the real-world example, look at Weblogger's index.adp page. Someone used Method #1 to conditionally add the RSS <link>, but this could get really ugly as I I'm trying to add a conditional RSD link, which would make the if/then situation twice as complex.

I'm leaning toward Method #2 - any suggestions?

Actually, there is a clean third way of doing this.

1. Create an new .adp file. Let's call it headerstuff.adp containing:

   
   <if @condition_1@>Item 1</if>
   <if @condition_2@>Item 2</if>
   

2. Call headerstuff.adp from the .tcl file you would like to use property header_stuff in:

   
   set cwd [file dirname [ad_conn file]]
   set headerstuff [template::adp_parse ${cwd}/headerstuff \
   	      [list \
   		   condition_1 $condition_1 \
   		   condition_2 $condition_2]]
   

3. Then pass the header_stuff property like so:

   
   <property name="header_stuff">@headerstuff@</property>
   

/Bart