Re: [Axiom-developer] A curious algebra failure

[Stephen Wilson]

From: Stephen Wilson <address@hidden>
Date: 11 Aug 2007 19:52:56 -0400
In-Reply-To: <address@hidden>
Message-ID: <address@hidden>
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Gabriel Dos Reis <address@hidden> writes:
>          pmatchWithSl(s,p,al) ==
>            s=$EmptyMode => nil
>            s=p => al
>            v:= ASSOC(p,al) => s=rest v or al
>            MEMQ(p,$PatternVariableList) => [[p,:s],:al]
>            null atom p and null atom s and_
>                    (al':= pmatchWithSl(first s,first p,al)) and
>              pmatchWithSl(rest s,rest p,al')

This function does not appear consistent.

   v:= ASSOC(p,al) => s=rest v or al

This line can have the function return true instead of an alist,
potentially spoiling the recursive calls and the subsequent binding to
al'.  Possibly (not totally sure) it should read:
        
   v:= ASSOC(p,al) and s=rest v => al

Simply redefining pname and )co MONAD.spad as you suggested does not
reveal the algebra failure you reported.  Is this occurring only upon
a complete rebuild for you?


Steve