Re: failure than error

[Erick Alphonse]

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