Re: failure than error

Takushi Tanaka wrote:

>Hello  Mr. Gnu-Prolog,
>
>When a goal is neither a fact nor a rule-head,
>Gnu-Prolog outputs "uncaught exception: error(...)".
>Though it is useful to check typing error, I want to
>treat the goal as new predicate for Prolog.
>
>Is it possible to treat the goal as failure rather
>than error?
>
>  
>
Hello,

you can also use set_prolog_flag(unknown,fail). This flag defines the 
behaviour when an unknown procedure is called.
 
 error (default)      an existence_error is raised
 warning                 a message is displayed then fails
 fail                        quietly fails