Re: [q-lang-users] Strong examples of Q equational programming wanted

[Albert G. <Dr....@t-...>]

Have you actually tried the Prolog solution? It looks to me as if those
rules only apply to the toplevel terms, so some recursive descent would
be needed. (In Q this is implicit because of the evaluation strategy.)

Greg Buchholz wrote:
> ...and a Prolog solution...
> 
> 
> diff(X,X,1).
> diff(U+V,X,Z) :- diff(U,X,Up), diff(V,X,Vp), simp(Up+Vp,Z),!.
> diff(U*V,X,C) :- diff(U,X,Up), diff(V,X,Vp),
>                  simp(U*Vp,A), simp(V*Up,B), simp(A+B,C),!.
> diff(_,X,0).
> 
> simp(0*X,0).
> simp(X*0,0).
> simp(1*X,X).
> simp(X*1,X).
> simp(0+X,X).
> simp(X+0,X).
> simp(X,X).

-- 
Dr. Albert Gr"af
Dept. of Music-Informatics, University of Mainz, Germany
Email:  Dr....@t-..., ag...@mu...
WWW:    http://www.musikinformatik.uni-mainz.de/ag