Re: [pure-lang-users] equations in Q vs Pure

[Eddie R. <er...@bm...>]

On Sat 26/07/08  2:49 AM , Albert Graef Dr....@t-... sent:
> Because that rule doesn't apply. Note that x^2+3*x+4*x+12 === 
> (x^2+3*x)+4*x+12 !== x^2+(3*x+4*x)+12. Pure doesn't do any rewriting 
> modulo AC (associativity+commutativity). Neither does Q, it will return
> exactly the same result with your equations.
> 
> What you can do to make this example work is add the following rule:
> 
> x+(a*b)+(c*d) = x+(a+c)*b if b === d;

Ah! Ok, the reason why I was getting the answer in Q is because I also had the associative rules of multiplication and addition.
(a+b)+c = a+(b+c);

It works but x^2+(7x+12) is kind of annoying to look at. The rule you give above makes the answer look nice.

Thanks,

e.r.