Re: [eclipse-clp-users] CHR rule remains as delayed goal

Hi Ulrich,

On 04/04/2011 10:25, Ulrich Scholz wrote:
> Hi,
>
> I'm using the library ech as part of a larger application.  Of late, running
> the application leaves a CHR rule as delayed goal:
>
> Delayed goals:
>          types : typeCHR(0, 0, 0, 0, 0, 0, killed)
>
> That's the first time I see a CHR rule as delayed goal and otherwise, the
> application seems to be correct.  Because I try to avoid leaving delayed
> goals (or, e.g., leaving choice points behind) and I want to understand what
> happens, I would like to know where and why this goal delays.
>
> But I have no clue.  Could you point me to some obvious starting points for
> my search?

A CHR constraint that is still in the CHR constraint store at the end of 
the execution is shown as a delayed goal. This is not necessarily 
incorrect. If you don't expect any CHR constraint to be left in the 
store, then you need to look at your CHR code to see why the constraint 
was not removed by your CHR rules. Unfortunately lib(ech) does not 
currently provide much debugging facilities, so that when you trace the 
execution of the CHR code, you see the "raw" ECLiPSe code (generated by 
lib(ech) from transforming your source CHR code), which is not easy to 
follow or map back to your source code.

Cheers,

Kish


-- 
This e-mail may contain confidential and privileged material for the
sole use of the intended recipient. Any review, use, distribution or
disclosure by others is strictly prohibited. If you are not the intended
recipient (or authorized to receive for the recipient), please contact
the sender by reply e-mail and delete all copies of this message.
Cisco Systems Limited (Company Number: 02558939), is registered in
England and Wales with its registered office at 1 Callaghan Square,
Cardiff, South Glamorgan CF10 5BT.