[web2py] misbehaves on a view of a controller with arguments

[Luis Goncalves]

Hello!

I have a  controller,  my_control(),  that can be called by itself,  or with 
two  arguments ,   ../default/my_control/AAA  or  .../BBB

In the associated view, my_control.html, I have some  href links that call a 
new controller:

              <a href="compute_value?id={{=stock.id}}">Compute Value</a>


If I was on the URL   
           .../default/my_control

      this works fine, because the href  becomes  
           .../default/compute_value?id=9

but if instead I am on the URL
           ../default/my_control/AAA

      then the href breaks, because it becomes
           .../default/AAA/compute_value?id=9

That is, it seems that <a href = ...>   only replaces the very last element 
from the URL


Is there a better way to generate a URL to my controller, irrespective of 
what page (with or without arguments)  I am on?

Thanks!!!

Luis.