Re: OPERATION NOT HANDLED

[srt@CS.UCLA.EDU]

>     ...For example, consider a procedure (or operation) that would behave
>like WHERE-DEFINED, except it would return NIL (rather than breaking) if the
>object didn't handle the WHERE-DEFINED operation (e.g., tables and
>read-tables don't).

I think the default body of DEFINE-OPERATION will handle this for you, i.e.,

        (define-operation (where-defined foo) nil)

will cause NIL to be returned if WHERE-DEFINED isn't defined.

 
    Scott R. Turner
    UCLA Computer Science     "Are we controlled by secret forces?"
    Domain: srt@ucla.cs.edu
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