Behavior when creating a new topic

I wanted to set a topic preference which contains a macro when creating a new autoincremented topic. So I put in my form (I use 'save'):

<input type="hidden" name="Set+id_elemento" value="%BA%NOP%SETOPIC%"/>

The problem at first was that the macro was expanded without evaluating the AUTOINC an even if I put the nop, the final value of the preference was "<topic>AUTOINC0000" instead of "<topic>XXXX". So i tried putting another nop inside the nop:

<input type="hidden" name="Set+id_elemento" value="%BA%%NOP%NOP%SETOPIC%"/>

But in the new topic the expaded variable look like it wasn't expanded:

%BASETOPIC%

instead of "<topic name>". When I looked at the text file of the topic I found that the nop was present:

%META:PREFERENCE{name="id_elemento" title="id_elemento" type="Set" value="%25BA<nop>SETOPIC%25"}%

So I need to enter to manage the preferences, even if I press cancel, the value is updated without the nop a I get what I wanted. But the thing is that each time I create a topic in that way, I need to enter the preferences for making it work so I can't get a thing between using 1 o 2 nops:

• 1 nop: all gets expanded before the AUTOINC is evaluated
• 2 nops: the second nop prevails

I don't know if there is a way to do what I wanted. Although I think the AUTOINC thing is not an elegant solution, it would be best if it were a macro of a plugin that gets expanded before saving or editing so we can use it for multiple purposes.

-- PompetardO - 10 Nov 2011