> > But, now I have to had an attribute wich do not have to tested and I can't > > figure the best way out. > > > > Would I investigate with inspector or the equal<%> interface. > > Both ways, I don't know how to do this. The doc is pretty brief about that.
> Are you saying that there are fields in your object that you don't > want to be part of the equality test? > Yes, that's exactly what I meant. > If so, it does sound like implementing the equal<%> interface may give > you enough power to express that idea. > (http://docs.racket-lang.org/reference/objectequality.html) And that's exactly what I was struggling to. > Here's a small example: > > ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;; > #lang racket > > (define ci-word% > (class* object% (equal<%>) > > ;; Initialization > (init-field word) > (super-new) > > ;; We define equality to ignore case: > (define/public (equal-to? other recur) > (string-ci=? word (get-field word other))) > > > ;; The hash codes need to be insensitive to casing as well. > ;; We'll just downcase the word and get its hash code. > (define/public (equal-hash-code-of hash-code) > (hash-code (string-downcase word))) > > (define/public (equal-secondary-hash-code-of hash-code) > (hash-code (string-downcase word))))) > > (define h (make-hash)) > (hash-set! h (new ci-word% [word "foobar"]) 'value) > > ;; Of course, we expect this lookup to succeed: > (hash-ref h (new ci-word% [word "foobar"])) > > ;; but it will also match case-insensitively: > (hash-ref h (new ci-word% [word "FoOBaR"])) Thank you very much. I tried all possibilities execept this way. What I can't figured out is the end of the doc with : The equal<%> interface is implemented with interface* and prop:equal +hash. I tought I had to implement the equal<%> interface myself. Thanks again for the help.
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