Re: [eclipse-clp-users] ECLiPSe's equivalence for "set_prolog_flag(unknown, fail)"

From: Kish Shen <kisshen_at_...5...>
Date: Sun, 04 Jan 2009 08:53:33 +0000
Huy Pham wrote:
> Greetings,
> 
> Would someone kindly let me know what is the ECLiPSe's equivalence for
> 
>     :- set_prolog_flag(unknown, fail).
> 
> Thanks,
> 
> Huy
> 
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Hi Huy,

You did not state which Prolog you are refering to. I assume you are 
referring to SWI-Prolog, where there is a set_prolog_flag/2, and the 
above changes the behaviour when you call an undefined predicate, it 
siliently fails rather than raise an error.

This is normally a bad idea, but if you really want to do it in ECLiPSe, 
you can redefine the error handler for the "calling an undefined 
procedure" error (event/error 68 -- you can find a list of the events in 
Appendix C of the User manual):

:- set_error_handler(68, fail/0).

Cheers,

Kish


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Received on Sun Jan 04 2009 - 09:22:31 CET

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