Re: let (d,k) = (g x y, h x d) ..

Serge D. Mechveliani wrote:

f' n m l = let (d,k) = (gcd n m, quot n d) in (k, l*k) ...

The intended program was

f n m l = let {d = gcd n m; k = quot n d} in (k, l*k)

But f' gives the intended results, at least in the GHC implementation. So that I did not notice the `error' for a long time.

Is really the Haskell pattern matching semantic so that f and f' are equivalent ?

But, in a lazy language it is the same, the let defs. are processed colaterally, the only difference is the (possibly optimized away) creation of the intermediate tuple (d,k). Jerzy Karczmarczuk