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Re: :around method with no primary
- To: MCL Bruce Lester <72110.1107@CompuServe.COM>
- Subject: Re: :around method with no primary
- From: bill@cambridge.apple.com (Bill St. Clair)
- Date: Mon, 6 Sep 1993 16:47:39 -0600
- Cc: info-mcl
At 9:45 PM 9/2/93 -0400, Bruce Lester wrote:
>I got an error message that I was unable to get rid of without creating a dummy
>primary method.
>
>I have a generic function with an around method that is applicable to all
>possible parameters. I use the around method to check the parameters for
>validity before calling CALL-NEXT-METHOD and the CLOS framework.
>
>Why do I have to have a primary method for a set of parameters that the around
>method handles?
That's how CLOS is specified. On page 797 of CLtL2 it says, "In standard
method combination, if there is an applicable method but no applicable primary
method, an error is signaled."
I suggest that you define a primary method that is applicable to all
possible parameters and have it signal an error.
Alternatively, you could define a new type of method combination that
behaves as you desire. This method will take longer (unless you're a
lot more adept at define-method-combination than I am).