Re: [eclipse-clp-users] Error_Handler

Dear Shrirang,

by looking at the list of available predicates:

http://eclipseclp.org/doc/bips/fullindex.html

and searching the string "error", I found that there is a predicate 
error_id that provides you the error message.

> [eclipse 2]: error_id(4,MGS).
>
> MGS = "instantiation fault"
> Yes (0.00s cpu)

this means that ECLiPSe was expecting to get an instantiated value, 
while it was not (i.e., it was a variable).

Example of a program that raises that error on backtracking:

goal(X):- member(X,[1,2,3]).
goal(X):- N is X+1.

> [eclipse 2]: goal(X).
>
> X = 1
> Yes (0.00s cpu, solution 1, maybe more) ? ;
>
> X = 2
> Yes (0.00s cpu, solution 2, maybe more) ? ;
>
> X = 3
> Yes (0.00s cpu, solution 3, maybe more) ? ;
> instantiation fault in +(X, 1, _167)
> Abort

Best,
Marco

On 27/11/15 03:45, Edgaonkar, Shrirang wrote:
> Dear clp users,
>
>
>
>   I have situation where I get one solution for my goal correctly. But on backtracking when there are no more solutions, I get the following call to error_handler and subsequently the program aborts.
>
>
>
>    error_handler(4, call(_1933), eclipse, eclipse)
>
>
>
> What are the possible conditions when I get such a call to error_handler ?
>
>
>
> Thanks and Regards,
>
> Shrirang Edgaonkar

-- 
Marco Gavanelli
Associate Professor
Ph.D. in Computer Science
Dept of Engineering
University of Ferrara
Tel/Fax  +39-0532-97-4833
http://docente.unife.it/marco.gavanelli